diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/src/declarative/declarativeui.qdoc | 99 | ||||
| -rw-r--r-- | doc/src/declarative/dynamicobjects.qdoc | 2 | ||||
| -rw-r--r-- | doc/src/declarative/elements.qdoc | 6 | ||||
| -rw-r--r-- | doc/src/declarative/qml-intro.qdoc | 414 | ||||
| -rw-r--r-- | doc/src/declarative/qtprogrammers.qdoc | 3 | ||||
| -rw-r--r-- | doc/src/external-resources.qdoc | 15 | ||||
| -rw-r--r-- | doc/src/getting-started/demos.qdoc | 18 | ||||
| -rw-r--r-- | doc/src/getting-started/gettingstartedqml.qdoc | 2044 | ||||
| -rw-r--r-- | doc/src/getting-started/gettingstartedqt.qdoc | 6 | ||||
| -rw-r--r-- | doc/src/qt4-intro.qdoc | 8 |
10 files changed, 1150 insertions, 1465 deletions
diff --git a/doc/src/declarative/declarativeui.qdoc b/doc/src/declarative/declarativeui.qdoc index 42189c0..ed8b734 100644 --- a/doc/src/declarative/declarativeui.qdoc +++ b/doc/src/declarative/declarativeui.qdoc @@ -33,7 +33,7 @@ dynamic, custom user interfaces. Qt Quick provides a declarative framework for building highly dynamic, -custom user interfaces from a rich set of \l {QML Elements}{QML elements}. +custom user interfaces from a rich set of \l{QML Elements}{QML elements}. Qt Quick helps programmers and designers collaborate to build the fluid user interfaces that are becoming common in portable consumer devices, such as mobile phones, media players, set-top boxes @@ -41,73 +41,74 @@ and netbooks. Qt Quick consists of the QtDeclarative C++ module, QML, and the integration of both of these into the Qt Creator IDE. Using the QtDeclarative C++ module, you can load and interact with QML files from your Qt application. -QML is an extension to \l -{http://www.ecma-international.org/publications/standards/Ecma-262.htm} -{JavaScript}, that provides a mechanism to declaratively build an -object tree of \l {QML Elements}{QML elements}. QML improves the -integration between JavaScript and Qt's existing QObject based type -system, adds support for automatic \l {Property Binding}{property -bindings} and provides \l {Network Transparency}{network transparency} -at the language level. +QML is an extension to \l{About JavaScript}{JavaScript}, that provides +a mechanism to declaratively build an object tree of +\l{QML Elements}{QML elements}. QML improves the integration between +JavaScript and Qt's existing QObject-based type system, adds support for +automatic \l{Property Binding}{property bindings} and provides +\l{Network Transparency}{network transparency} at the language level. -The \l {QML Elements}{QML elements} are a sophisticated set of +The \l{QML Elements}{QML elements} are a sophisticated set of graphical and behavioral building blocks. These different elements -are combined together in \l {QML Documents}{QML documents} to build +are combined together in \l{QML Documents}{QML documents} to build components ranging in complexity from simple buttons and sliders, to -complete internet-enabled applications like a \l -{http://www.flickr.com}{Flickr} photo browser. +complete Internet-enabled applications like a photo browser for the +popular \l{http://www.flickr.com}{Flickr} photo-sharing site. -Qt Quick builds on \l {QML for Qt programmers}{Qt's existing -strengths}. QML can be be used to incrementally extend an existing -application or to build completely new applications. QML is fully \l -{Extending QML in C++}{extensible from C++} through the QtDeclarative Module. +Qt Quick builds on \l{QML for Qt programmers}{Qt's existing strengths}. +QML can be be used to incrementally extend an existing application or +to build completely new applications. QML is fully +\l{Extending QML in C++}{extensible from C++} through the QtDeclarative +Module. \section1 Getting Started \list -\o \l {Introduction to the QML language} -\o \l {QML Tutorial}{Tutorial: 'Hello World'} -\o \l {QML Advanced Tutorial}{Tutorial: 'Same Game'} -\o \l {QML Examples and Demos} -\o \l {QML for Qt programmers} +\o \l{Introduction to the QML language} +\o \l{QML Tutorial}{Tutorial: 'Hello World'} +\o \l{QML Advanced Tutorial}{Tutorial: 'Same Game'} +\o \l{QML Examples and Demos} +\o \l{QML for Qt Programmers} +\o \l{Getting Started Programming with QML} +\o \l{Beginning Qt Quick} \endlist \section1 Core QML Features \list -\o \l {QML Documents} -\o \l {Property Binding} -\o \l {Network Transparency} -\o \l {QML Scope} -\o \l {Integrating JavaScript} -\o \l {Data Models} -\o \l {anchor-layout.html}{Anchor-based Layout} -\o \l {qdeclarativestates.html}{States} -\o \l {qdeclarativeanimation.html}{Animation} -\o \l {qdeclarativefocus.html}{Keyboard Focus} -\o \l {qdeclarativemodules.html}{Modules} -\o \l {Extending types from QML} -\o \l {qdeclarativedynamicobjects.html}{Dynamic Object Creation} -\o \l {qmlruntime.html}{The Qt Declarative Runtime} +\o \l{QML Documents} +\o \l{Property Binding} +\o \l{Network Transparency} +\o \l{QML Scope} +\o \l{Integrating JavaScript} +\o \l{Data Models} +\o \l{Anchor-based Layout in QML} +\o \l{QML States} +\o \l{QML Animation} +\o \l{Keyboard Focus in QML} +\o \l{QML Modules} +\o \l{Extending types from QML} +\o \l{Dynamic Object Management in QML} +\o \l{Qt Declarative UI Runtime} \endlist \section1 Using QML with C++ \list -\o \l {Using QML in C++ Applications} -\o \l {Integrating QML with existing Qt UI code} -\o \l {Tutorial: Writing QML extensions with C++} -\o \l {Extending QML in C++} +\o \l{Using QML in C++ Applications} +\o \l{Integrating QML with existing Qt UI code} +\o \l{Tutorial: Writing QML extensions with C++} +\o \l{Extending QML in C++} \endlist \section1 Reference \list -\o \l {QML Elements} -\o \l {QML Global Object} -\o \l {QML Internationalization} -\o \l {QML Security} -\o \l {QtDeclarative Module} -\o \l {Debugging QML} -\o \l {QML Viewer} -\o \l {QML Performance} -\o \l {QML Coding Conventions} +\o \l{QML Elements} +\o \l{QML Global Object} +\o \l{QML Internationalization} +\o \l{QML Security} +\o \l{QtDeclarative Module} +\o \l{Debugging QML} +\o \l{QML Viewer} +\o \l{QML Performance} +\o \l{QML Coding Conventions} \endlist */ diff --git a/doc/src/declarative/dynamicobjects.qdoc b/doc/src/declarative/dynamicobjects.qdoc index 997f601..e735bce 100644 --- a/doc/src/declarative/dynamicobjects.qdoc +++ b/doc/src/declarative/dynamicobjects.qdoc @@ -27,7 +27,7 @@ /*! \page qdeclarativedynamicobjects.html -\title Dynamic Object Management +\title Dynamic Object Management in QML QML provides a number of ways to dynamically create and manage QML objects. The \l{Loader}, \l{Repeater}, \l{ListView}, \l{GridView} and \l{PathView} elements diff --git a/doc/src/declarative/elements.qdoc b/doc/src/declarative/elements.qdoc index c2930b3..55b71e1 100644 --- a/doc/src/declarative/elements.qdoc +++ b/doc/src/declarative/elements.qdoc @@ -26,11 +26,11 @@ ****************************************************************************/ /*! -\page qdeclarativeelements.html +\page qmlelements.html \target elements \title QML Elements -The following table lists the QML elements provided by the \l {QtDeclarative}{Qt Declarative} module. +The following table lists the QML elements provided by the \l{QtDeclarative} module. \table \header \o {2,1} \bold {Basic Visual Items} @@ -54,7 +54,7 @@ The following table lists the QML elements provided by the \l {QtDeclarative}{Qt \row \o \l {Flickable} \o Provides a surface that can be "flicked" \row \o \l {Flipable} \o Provides a surface that produces flipping effects \row \o \l {GestureArea} (experimental) \o Enables simple gesture handling - + \header \o {2,1} \bold {States} \row \o \l {State} \o Defines sets of configurations of objects and properties \row \o \l {PropertyChanges} \o Describes property changes within a state diff --git a/doc/src/declarative/qml-intro.qdoc b/doc/src/declarative/qml-intro.qdoc index fbab001..69dd500 100644 --- a/doc/src/declarative/qml-intro.qdoc +++ b/doc/src/declarative/qml-intro.qdoc @@ -28,14 +28,11 @@ /*! - -\page qml-intro.html +\page qml-intro.html \title Beginning Qt Quick - \section1 Overview - QML is a high level, scripted language. Its commands, more correctly \e elements, leverage the power and efficiency of the Qt libraries to make easy to use commands that perform intuitive functions. Draw a rectangle, display an image at @@ -61,12 +58,7 @@ would be a property. The basic syntax of an \l {QML Elements}{element} is - \code - SomeElement { - id: myObject - ... some other things here ... - } - \endcode +\snippet doc/src/snippets/declarative/qml-intro/basic-syntax.qml basic syntax Here we are defining a new object. We specify its 'type' first as SomeElement. Then within matching braces { ... } we specify the various parts of our @@ -90,61 +82,38 @@ want a rectangle that is 500 pixels by 400 pixels in the x and y directions We can implement this \l Rectangle with these properties this way - \code - import Qt 4.7 - - // This is a comment. And below myRectangle is defined. - Rectangle { - id: myRectangle - width: 500 - height: 400 - } - \endcode +\quotefile doc/src/snippets/declarative/qml-intro/rectangle.qml This is a valid QML script. To run it, copy it and save it to a file, say -myexample.qml, and on the command line run the command +myexample.qml, and on the command line run the following command: - \code - qmlviewer myexample.qml - \endcode +\code +qmlviewer myexample.qml +\endcode On Mac OS X, open the "QMLViewer" application instead and open the \c myexample.qml file, or run it from the command line: - \code - QMLViewer.app/Contents/MacOS/QMLViewer myexample.qml - \endcode - +\code +QMLViewer.app/Contents/MacOS/QMLViewer myexample.qml +\endcode It will create a very boring rectangle in its own window. - \section1 Hello World! We can now add some color and text to make a Hello World QML program. -\l Rectangle has the property \l {Rectangle::color}{color} to produce a +\l Rectangle has the property \l{Rectangle::color}{color} to produce a background color. Text is handled by a different element called \l Text. We need to create a -\l Text object inside the \l Rectangle and set its \l {Text::text}{text} -property to "Hello World!". So to set the text to 'Hello world' and the +\l Text object inside the \l Rectangle and set its \l{Text::}{text} +property to "Hello World!". So to set the text to "Hello world" and the background colour to light gray, - \code - import Qt 4.7 - - Rectangle { - id: myRectangle - width: 500 - height: 400 - - Text { text: "Hello World!" } - - color: "lightgray" - } - \endcode +\quotefile doc/src/snippets/declarative/qml-intro/hello-world1.qml \section1 Hello World Again @@ -158,12 +127,7 @@ position belongs to the \l Text element so we set the position inside its definition. Note that we separate different QML statements on the same line with a semi-colon, or we could have simply put each statement on a new line - \code - Text { - text: "<h2>Hello World</h2>"; color: "darkgreen" - x: 100; y:100 - } - \endcode +\snippet doc/src/snippets/declarative/qml-intro/hello-world2.qml updated text Not only did we reposition the text, but the text was altered by adding HTML tags to change the font size. The text color was also changed from the @@ -174,13 +138,7 @@ We could also have used a hexadecimal string for the RGB (red-green-blue, as #rrggbb) values of the color similar to the method used in HTML. For example, mostly blue with a green tint, - \code - Text { - text: "<h1>Hello world again</h1>" - color: "#002288" - x: 100; y: 100 - } - \endcode +\snippet doc/src/snippets/declarative/qml-intro/hello-world3.qml updated text All of these changes occurred within the \l Text object which is the scope of these property changes. @@ -198,11 +156,7 @@ source of the image, the path to the file, is a URL. Therefore the file can be local: \e {mydir/myimage1.png}. Or it can be remote: \e {"http://www.example.com/images/myimage1.png"}. - \code - Image { - source: "images/qt-logo.png" - } - \endcode +\snippet doc/src/snippets/declarative/qml-intro/hello-world4.qml added an image This displays the image, as we would expect, at the top left of the window. The position of the default x = 0, y = 0 coordinate. The example here uses @@ -213,44 +167,12 @@ Let us reposition the image and enlarge it. Place it at the same 'x' offset as the "Hello world again" text, but put it another 50 pixels below the text, also make it 150 by 150 pixels in size, - \code - Image { - source: "images/qt-logo.png" - x: 100; y: 150 - width: 150; height: 150 - } - \endcode +\snippet doc/src/snippets/declarative/qml-intro/hello-world5.qml positioning the image Adding the Hello World example, with the text and the image example we can write a simple piece of QML that starts to look a bit better. - \code - import Qt 4.7 - - Rectangle { - id: myRectangle - width: 500 - height: 400 - - // A light gray background - color: "lightgray" - - // Position and color some text - Text { - text: "<h1>Hello world again</h1>" - color: "darkgreen" - x: 100; y: 100 - } - - // Using the opportunity to resize the image. - Image { - source: "images/qt-logo.png" - x: 100; y: 150 - width: 150; height: 150 - } - - } - \endcode +\quotefile doc/src/snippets/declarative/qml-intro/hello-world5.qml The result is still quite simple @@ -281,22 +203,7 @@ If we want to position an image at the bottom of the rectangle it is inside. I have to specify that the bottom of the image is also at the bottom of the rectangle - \code - import Qt 4.7 - - Rectangle { - id: myWin - width: 500 - height: 400 - - Image { - id: image1 - source: "images/qt-logo.png" - width: 150; height: 150 - anchors.bottom: myWin.bottom - } - } - \endcode +\quotefile doc/src/snippets/declarative/qml-intro/anchors1.qml This places the logo at the bottom left of the window. @@ -315,25 +222,7 @@ the bottomMargin property is used. So the new actions for the script are Encoded into QML the script becomes - \code - import Qt 4.7 - - Rectangle { - id: myWin - width: 500 - height: 400 - - Image { - id: image1 - source: "images/qt-logo.png" - width: 150; height: 150 - anchors.bottom: myWin.bottom - anchors.horizontalCenter: myWin.horizontalCenter - anchors.bottomMargin: 10 - } - } - \endcode - +\quotefile doc/src/snippets/declarative/qml-intro/anchors2.qml Run this and resize the window. You will see that now the position of the image adjusts during the resize. @@ -344,14 +233,7 @@ You can also add another object say a block of descriptive text and place it above or below the image or to the side. This code places some text just above the image - \code - Text { - text: "<h2>The Qt Logo</h2>" - anchors.bottom: image1.top - anchors.horizontalCenter: myWin.horizontalCenter - anchors.bottomMargin: 15 - } - \endcode +\snippet doc/src/snippets/declarative/qml-intro/anchors3.qml adding some text \image qml-intro-anchors3.png @@ -359,17 +241,15 @@ above the image referencing these properties from another object we use the property directly, instead of saying: - \code - myRectangle.anchors.top // Wrong - \endcode +\qml +myRectangle.anchors.top // Wrong +\endqml we use - \code - myRectangle.top // Correct - \endcode - - +\qml +myRectangle.top // Correct +\endqml \section1 Transformations @@ -391,9 +271,9 @@ Rotation of text was also suggested. It could also be useful to scale the text. We can do both. The \l {Item::transform}{transform} property is a \e list of \l Transform elements, so using the list syntax - \code - myList: [ listElement1, listElement2, ... } ] - \endcode +\qml +myList: [ listElement1, listElement2, ... } ] +\endqml we can produce a list of transformations. @@ -402,46 +282,7 @@ vertically by a factor of 1.5 and by 1.2 horizontally. Using the example above as the basis for this we have, - \code - import Qt 4.7 - - Rectangle { - id: myWin - width: 500 - height: 400 - - Image { - id: image1 - source: "images/qt-logo.png" - width: 150; height: 150 - anchors.bottom: myWin.bottom - anchors.horizontalCenter: myWin.horizontalCenter - anchors.bottomMargin: 10 - - transform: Rotation { - origin.x: 75; origin.y: 75 - axis{ x: 0; y: 0; z:1 } angle: -90 - } - - } - - Text { - text: "<h2>The Qt Logo -- taking it easy</h2>" - anchors.bottom: image1.top - anchors.horizontalCenter: myWin.horizontalCenter - anchors.bottomMargin: 15 - - transform: [ - Scale { xScale: 1.5; yScale: 1.2 } , - - Rotation { - origin.x: 75; origin.y: 75 - axis{ x: 0; y: 0; z:1 } angle: -45 - } - ] - } - } - \endcode +\quotefile doc/src/snippets/declarative/qml-intro/transformations1.qml The code block in \c image1 starting with \c transform specifies that the \l {Item::transform}{transform} property will be a Rotation through -90 @@ -479,30 +320,7 @@ from \l Item. The rotation property is a real number that specifies the angle in a clockwise direction for the rotation of the object. Here is the code for our animated rotating image. - \code - import Qt 4.7 - - Rectangle { - id: mainRec - width: 600 - height: 400 - - Image { - id: image1 - source: "images/qt-logo.png" - x: 200; y: 100 - width: 100; height: 100 - - // Animate a rotation - transformOrigin: Item.Center - NumberAnimation on rotation { - from: 0; to: 360 - duration: 2000 - loops: Animation.Infinite - } - } - } - \endcode +\quotefile doc/src/snippets/declarative/number-animation1.qml The \c {transformOrigin: Item.Center} is redundant since this is the default axis of rotation anyway. But if you change \c Center to \c BottomRight you @@ -515,32 +333,7 @@ combination. For example, if the task had been to animate the rotation about the y-axis passing through the center of the image then the following code would do it. - \code - import Qt 4.7 - - Rectangle { - id: mainRec - width: 600 - height: 400 - - Image { - id: image1 - source: "images/qt-logo.png" - x: 200; y: 100 - width: 100; height: 100 - - // Animate a rotation - transform: Rotation { - origin.x: 50; origin.y: 50; axis {x:0; y:1; z:0} angle:0 - NumberAnimation on angle { - from: 0; to: 360; - duration: 3000; - loops: Animation.Infinite - } - } - } - } - \endcode +\quotefile doc/src/snippets/declarative/number-animation2.qml Here there is a rectangle 600 by 400 pixels. Placed within that rectangle is an image 100 by 100 pixels. It is rotated about the center of the image @@ -569,31 +362,7 @@ will be animating the position and the size of the image. First create two images - \code - import Qt 4.7 - - Rectangle { - id: mainRec - width: 600 - height: 400 - z: 0 - - Image { - id: image1 - source: "images/qt-logo.png" - x: 20; y: 20 ; z: 1 - width: 100; height: 100 - } - - Image { - id: image2 - source: "images/qt-logo.png" - width: 100; height: 100 - x: (mainRec.width - 100)/2; y: (mainRec.height - 100)/2 - z: 2 - } - } - \endcode +\quotefile doc/src/snippets/declarative/sequential-animation1.qml We will add to 'image1' a SequentialAnimation from x = 20 to the target of x = 450. The 'from' values will be used because we will be repeating the @@ -606,14 +375,7 @@ between the x values and over a given duration. After the NumberAnimation there will be a PauseAnimation that will pause the animation for 500 milliseconds (half a second) simply for the visual effect. - \code - SequentialAnimation on x { - loops: Animation.Infinite - NumberAnimation { from: 20; to: 450; easing.type: "InOutQuad"; -duration: 2000 } - PauseAnimation { duration: 500 } - } - \endcode +\snippet doc/src/snippets/declarative/sequential-animation2.qml adding a sequential animation A similar block of code is written for the animation of the 'y' value of the position. @@ -628,54 +390,7 @@ and image1 to 1 and image2 to 2 then image2 will be in the foreground and image1 in the background. When image1 passes image2 it will pass behind it. The completed code looks like - \code - Rectangle { - id: mainRec - width: 600 - height: 400 - z: 0 - - Image { - id: image2 - source: "images/qt-logo.png" - width: 100; height: 100 - x: (mainRec.width - 100)/2; y: (mainRec.height - 100)/2 - z: 2 - } - - Image { - id: image1 - source: "images/qt-logo.png" - x: 20; y: 20 ; z: 1 - width: 100; height: 100 - - SequentialAnimation on x { - loops: Animation.Infinite - NumberAnimation { - from: 20; to: 450 - easing.type: "InOutQuad"; duration: 2000 - } - PauseAnimation { duration: 500 } - } - - SequentialAnimation on y { - loops: Animation.Infinite - NumberAnimation { - from: 20; to: 250 - easing.type: "InOutQuad"; duration: 2000 - } - PauseAnimation { duration: 500 } - } - - SequentialAnimation on scale { - loops: Animation.Infinite - NumberAnimation { from: 1; to: 0.5; duration: 1000 } - NumberAnimation { from: 0.5; to: 1; duration: 1000 } - PauseAnimation { duration: 500 } - } - } - } - \endcode +\quotefile doc/src/snippets/declarative/sequential-animation3.qml The \c {easing.type} has many options, expressed as a string. It specifies the kind of equation that describes the acceleration of the property value, not @@ -756,60 +471,7 @@ will be the default state. We will just go to 'night' by clicking and holding the left mouse button down, releasing the mouse button will reverse the process - \code - import Qt 4.7 - - Rectangle { - id: mainRectangle - width: 600 - height: 400 - color: "black" - - Rectangle { - id: sky - width: 600 - height: 200 - y: 0 - color: "lightblue" - } - - Rectangle { - id: ground - width: 600; height: 200 - y: 200 - color: "green" - } - - MouseArea { - id: mousearea - anchors.fill: mainRectangle - } - - states: [ State { - name: "night" - when: mousearea.pressed == true - PropertyChanges { target: sky; color: "darkblue" } - PropertyChanges { target: ground; color: "black" } - }, - State { - name: "daylight" - when: mousearea.pressed == false - PropertyChanges { target: sky; color: "lightblue" } - PropertyChanges { target: ground; color: "green" } - } - ] - - transitions: [ Transition { - from: "daylight"; to: "night" - ColorAnimation { duration: 1000 } - }, - Transition { - from: "night"; to: "daylight" - ColorAnimation { duration: 500 } - } - ] - } - \endcode +\quotefile doc/src/snippets/declarative/states1.qml Several new things appear in this sample. Firstly, we use a \l MouseArea element to detect mouse clicks in the \e mainRectangle. Secondly, we use diff --git a/doc/src/declarative/qtprogrammers.qdoc b/doc/src/declarative/qtprogrammers.qdoc index 68d56bf..c0639db 100644 --- a/doc/src/declarative/qtprogrammers.qdoc +++ b/doc/src/declarative/qtprogrammers.qdoc @@ -26,10 +26,9 @@ ****************************************************************************/ /*! - \page qtprogrammers.html \target qtprogrammers -\title QML for Qt programmers +\title QML for Qt Programmers \section1 Overview diff --git a/doc/src/external-resources.qdoc b/doc/src/external-resources.qdoc index e901124c..61620f5 100644 --- a/doc/src/external-resources.qdoc +++ b/doc/src/external-resources.qdoc @@ -428,3 +428,18 @@ \externalpage http://developer.symbian.org/wiki/index.php/Deploying_a_Qt_Application \title Deploying a Qt Application article */ + +/*! + \externalpage http://www.ecma-international.org/publications/standards/Ecma-262.htm + \title ECMAScript Language Specification +*/ + +/*! + \externalpage https://developer.mozilla.org/en/JavaScript + \title JavaScript +*/ + +/*! + \externalpage https://developer.mozilla.org/en/JavaScript/About_JavaScript + \title About JavaScript +*/ diff --git a/doc/src/getting-started/demos.qdoc b/doc/src/getting-started/demos.qdoc index ef16224..719c861 100644 --- a/doc/src/getting-started/demos.qdoc +++ b/doc/src/getting-started/demos.qdoc @@ -46,7 +46,7 @@ \o \inlineimage qtdemo-small.png \o If you run the \l{Examples and Demos Launcher}, you'll see many of Qt's widgets in action. - + The \l{Qt Widget Gallery} also provides overviews of selected Qt widgets in each of the styles used on various supported platforms. \endtable @@ -134,15 +134,23 @@ \section1 QtWebKit \list - \o \l{Web Browser} demonstrates how Qt's \l{QtWebKit Module}{WebKit module} - can be used to implement a small Web browser. + \o \l{Web Browser} demonstrates how Qt's \l{QtWebKit} module can be used to + implement a small Web browser. + \endlist + + \section1 Multimedia + + \list + \o \l{demos/spectrum}{Spectrum Analyser} shows how the \l{QtMultimedia} + module can be used to manipulate audio as it is played. \endlist \section1 Phonon \list - \o \l{demos/qmediaplayer}{Media Player} demonstrates how the \l{Phonon Module} can be - used to implement a basic media player application. + \o \l{demos/qmediaplayer}{Media Player} demonstrates how the + \l{Phonon Module}{Phonon module} can be used to implement a basic media player + application. \endlist \note The Phonon demos are currently not available for the MinGW platform. diff --git a/doc/src/getting-started/gettingstartedqml.qdoc b/doc/src/getting-started/gettingstartedqml.qdoc index 2bfb71c..885e6ce 100644 --- a/doc/src/getting-started/gettingstartedqml.qdoc +++ b/doc/src/getting-started/gettingstartedqml.qdoc @@ -26,1025 +26,1025 @@ ****************************************************************************/ /*! - \page qml-textEditor.html - - \title Getting Started programming with QML - \ingroup gettingStarted - - Welcome to the world of QML - the declarative UI language. In this Getting - Started guide, we will create a simple text editor application using QML. - After reading this guide, you should be ready to develop your own applications - using QML and Qt C++. - - \section1 QML to Build User Interfaces - - The application we are building is a simple text editor that will load, save, - and perform some text manipulation. This guide will consist of two parts. The - first part will involve designing the application layout and behaviors using - declarative language in QML. For the second part, file loading and saving will - be implemented using Qt C++. Using - \l {The Meta-Object System}{Qt's Meta-Object System}, we can expose C++ functions - as properties that QML elements can use. Utilizing QML and Qt C++, we can - efficiently decouple the interface logic from the application logic. - - \image qml-texteditor5_editmenu.png - - To run the QML example code, merely provide the included \l{QML Viewer}{qmlviewer} - tool with the QML file as the argument. The C++ portion of this tutorial assumes - that the reader possesses basic knowledge of Qt's compilation procedures. - - Tutorial chapters: - \list 1 - \o \l {Defining a Button and a Menu}{Defining a Button and a Menu} - \o \l {Implementing a Menu Bar}{Implementing a Menu Bar} - \o \l {Building a Text Editor}{Building a Text Editor} - \o \l {Decorating the Text Editor}{Decorating the Text Editor} - \o \l {Extending QML using Qt C++}{Extending QML using Qt C++} - \endlist - - \section1 Defining a Button and a Menu - - \section2 Basic Component - a Button - - We start our text editor by building a button. Functionally, a button has a mouse - sensitive area and a label. Buttons perform actions when a user presses the button. - - In QML, the basic visual item is the \l {Rectangle}{Rectangle} element. The - \c Rectangle element has properties to control the element's appearance and location. - - \code - import Qt 4.7 - Rectangle { - id: simplebutton - color: "grey" - width: 150; height: 75 - - Text{ - id: buttonLabel - anchors.centerIn: parent - text: "button label" - } - } - \endcode - - First, the \c { import Qt 4.7 } allows the qmlviewer tool to import the QML elements - we will later use. This line must exist for every QML file. Notice that the version - of Qt modules is included in the import statement. - - This simple rectangle has a unique identifier, \c simplebutton, which is bound to the - id property. The \c Rectangle element's properties are bound to values by listing the - property, followed by a colon, then the value. In the code sample, the color \c grey - is bound to the the Rectangle's \c color property. Similarly, we bind the \c width - and \c height of the Rectangle. - - The \l {Text}{Text} element is a non-editable text field. We name this \c Text element - \c buttonLabel. To set the string content of the Text field, we bind a value to the - \c text property. The label is contained within the Rectangle and in order to center - it in the middle, we assign the \c anchors of the Text element to its parent, which - is called \c simplebutton. Anchors may bind to other items' anchors, allowing layout - assignments simpler. - - We shall save this code as \c SimpleButton.qml. Running qmlviewer with the file as the - argument will display the grey rectangle with a text label. - - \image qml-texteditor1_simplebutton.png - - To implement the button click functionality, we can use QML's event handling. QML's event - handling is very similar to \l {Signals & Slots}{Qt's signal and slot} mechanism. Signals - are emitted and the connected slot is called. - - \code - Rectangle{ - id:simplebutton - ... - - MouseArea{ - id: buttonMouseArea - - anchors.fill: parent //anchor all sides of the mouse area to the rectangle's anchors - //onClicked handles valid mouse button clicks - onClicked: console.log(buttonLabel.text + " clicked" ) - } - } - \endcode - - We include a \l{MouseArea} element in our simplebutton. \c MouseArea elements describe - the interactive area where mouse movements are detected. For our button, we anchor the - whole MouseArea to its parent, which is \c simplebutton. The \c anchors.fill syntax is - one way of accessing a specific property called \c fill inside a group of properties - called \c anchors. QML uses \l {Anchor-based Layout in QML}{anchor based layouts} where - items can anchor to another item, creating robust layouts. - - The \c MouseArea has many signal handlers that are called during mouse movements within - the specfied \c MouseArea boundaries. One of them is \c onClicked and it is called - whenever the acceptable mouse button is clicked, the left click being the default. We - can bind actions to the onClicked handler. In our example, \c console.log() outputs text - whenever the mouse area is clicked. The function \c console.log() is a useful tool for - debugging purposes and for outputting text. - - The code in \c SimpleButton.qml is sufficient to display a button on the screen and - output text whenever it is clicked with a mouse. - - \code - Rectangle { - id:Button - ... - - property color buttonColor: "lightblue" - property color onHoverColor: "gold" - property color borderColor: "white" - - signal buttonClick() - onButtonClick: { - console.log(buttonLabel.text + " clicked" ) - } - - MouseArea{ - onClicked: buttonClick() - hoverEnabled: true - onEntered: parent.border.color = onHoverColor - onExited: parent.border.color = borderColor - } - - //determines the color of the button by using the conditional operator - color: buttonMouseArea.pressed ? Qt.darker(buttonColor, 1.5) : buttonColor - } - \endcode - - A fully functioning button is in \c Button.qml. The code snippets in this article - have some code omitted, denoted by ellipses because they were either introduced - earlier in the previous sections or irrelevant to the current code discussion. - - Custom properties are declared using the \c {property type name} syntax. In the - code, the property \c buttonColor, of type \c color, is declared and bound to - the value \c{"lightblue"}. The \c buttonColor is later used in a conditional - operation to determine the buttons's fill color. Note that property value - assignment is possible using the \c= equals sign, in addition to value binding - using the \c : colon character. Custom properties allow internal items to be - accessible outside of the Rectangle's scope. There are basic - \l{QML Basic Types}{QML types} such as \c int, \c string, \c real, as well as - a type called \c variant. - - By binding the \c onEntered and \c onExited signal handlers to colors, the - button's border will turn yellow when the mouse hovers above the button and - reverts the color when the mouse exits the mouse area. - - A \c buttonClick() signal is declared in \c Button.qml by placing the \c signal - keyword in front of the signal name. All signals have their handlers automatically - created, their names starting with \c on. As a result, the \c onButtonClick is - \c buttonClick's handler. The \c onButtonClick is then assigned an action to - perform. In our button example, the \c onClicked mouse handler will simply call - \c onButtonClick, which displays a text. The \c onButtonClick enables outside - objects to access the \c {Button}'s mouse area easily. For example, items may - have more than one \c MouseArea declarations and a \c buttonClick signal can - make the distinction between the several \c MouseArea signal handlers better. - - We now have the basic knowledge to implement items in QML that can handle - basic mouse movements. We created a \c Text label inside a \c Rectangle, - customized its properties, and implemented behaviors that respond to mouse - movements. This idea of creating elements within elements is repeated - throughout the text editor application. - - This button is not useful unless used as a component to perform an action. - In the next section, we will soon create a menu containing several of these - buttons. - - \image qml-texteditor1_button.png - - \section2 Creating a Menu Page - - Up to this stage, we covered how to create elements and assign behaviors inside - a single QML file. In this section, we will cover how to import QML elements and how - to reuse some of the created components to build other components. - - Menus display the contents of a list, each item having the ability to perform an action. - In QML, we can create a menu in several ways. First, we will create a menu containing - buttons which will eventually perform different actions. The menu code is in - \c FileMenu.qml. - - \code - import Qt 4.7 \\import the main Qt QML module - import “folderName” \\import the contents of the folder - import “Button.qml” \\import a QML file - import “NewButton.qml” as ButtonModule \\import a QML file and give it a name - import “script.js” as Script \\import a Javascript file and name it as Script - \endcode - - To use the \c Button element in \c FileMenu.qml, we need to import \c Button.qml. - The syntax shown above, shows how to use the \c import keyword. However, the - \c {import Button.qml} is not necessary; qmlviewer will import all the contents - of the current directory. We can directly create a \c Button element by declaring - \c Button{}, similar to a \c Rectangle{} declaration. - - \code - In FileMenu.qml: - - Row{ - anchors.centerIn: parent - spacing: parent.width/6 - - Button{ - id: loadButton - buttonColor: "lightgrey" - label: "Load" - } - Button{ - buttonColor: "grey" - id: saveButton - label: "Save" - } - Button{ - id: exitButton - label: "Exit" - buttonColor: "darkgrey" - - onButtonClick: Qt.quit() - } - } - \endcode - - In \c FileMenu.qml, we declare three \c Button elements. They are declared - inside a \l {Row}{Row} element, a positioner that will position its children - along a vertical row. The \c Button declaration resides in Button.qml, - which is the same as the \c Button.qml we used in the previous section. - New property bindings can be declared within the newly created buttons, - effectively overwriting the properties set in \c Button.qml. The button - called \c exitButton will quit and close the window when it is clicked. - Note that the signal handler \c onButtonClick in \c Button.qml will be - called in addition to the \c onButtonClick handler in \c exitButton. - - \image qml-texteditor1_filemenu.png - - The \c Row declaration is declared in a \c Rectangle, creating a rectangle - container for the row of buttons. This additional rectangle creates an indirect - way of organizing the row of buttons inside a menu. - - The declaration of the edit menu is very similar at this stage. The menu has - buttons that have the labels: \c Copy, \c Paste, and \c {Select All}. - - \image qml-texteditor1_editmenu.png - - Armed with our knowledge of importing and customizing previously made - components, we may now combine these menu pages to create a menu bar, - consisting of buttons to select the menu, and look at how we may structure - data using QML. - - \section1 Implementing a Menu Bar - - Our text editor application will need a way to display menus using a menu bar. - The menu bar will switch the different menus and the user can choose which menu - to display. Menu switching implies that the menus need more structure than - merely displaying them in a row. QML uses models and views to structure data - and display the structured data. - - \section2 Using Data Models and Views - - QML has different \l {Data Models}{data views} that display - \l {Data Models}{data models}. Our menu bar will display the menus in a list, - with a header that displays a row of menu names. The list of menus are declared - inside a \c VisualItemModel. The \l{VisualItemModel}{\c VisualItemModel} - element contains items that already have views such as \c Rectangle elements - and imported UI elements. Other model types such as the \l {ListModel}{\c ListModel} - element need a delegate to display their data. - - We declare two visual items in the \c menuListModel, the \c FileMenu and the - \c EditMenu. We customize the two menus and display them using a - \l {ListView}{ListView}. The \c MenuBar.qml file contains the QML declarations - and a simple edit menu is defined in \c EditMenu.qml. - - \code - VisualItemModel{ - id: menuListModel - FileMenu{ - width: menuListView.width - height: menuBar.height - color: fileColor - } - EditMenu{ - color: editColor - width: menuListView.width - height: menuBar.height - } - } - \endcode - - The \l {ListView}{ListView} element will display a model according to a delegate. - The delegate may declare the model items to display in a \c Row element or display - the items in a grid. Our \c menuListModel already has visible items, therefore, - we do not need to declare a delegate. - - \code - ListView{ - id: menuListView - - //Anchors are set to react to window anchors - anchors.fill:parent - anchors.bottom: parent.bottom - width:parent.width - height: parent.height - - //the model contains the data - model: menuListModel - - //control the movement of the menu switching - snapMode: ListView.SnapOneItem - orientation: ListView.Horizontal - boundsBehavior: Flickable.StopAtBounds - flickDeceleration: 5000 - highlightFollowsCurrentItem: true - highlightMoveDuration:240 - highlightRangeMode: ListView.StrictlyEnforceRange - } - \endcode - - Additionally, \c ListView inherits from \l {Flickable}{\c Flickable}, making - the list respond to mouse drags and other gestures. The last portion of the - code above sets \c Flickable properties to create the desired flicking movement - to our view. In particular,the property \c highlightMoveDuration changes the - duration of the flick transition. A higher \c highlightMoveDuration value - results in slower menu switching. - - The \c ListView maintains the model items through an \c index and each visual - item in the model is accessible through the \c index, in the order of the - declaration. Changing the \c currentIndex effectively changes the highlighted - item in the \c ListView. The header of our menu bar exemplify this effect. - There are two buttons in a row, both changing the current menu when clicked. - The \c fileButton changes the current menu to the file menu when clicked, - the \c index being \c 0 because \c FileMenu is declared first in the - \c menuListModel. Similarly, the \c editButton will change the current - menu to the \c EditMenu when clicked. - - The \c labelList rectangle has \c z value of \c 1, denoting that it is displayed - at the front of the menu bar. Items with higher \c z values are displayed in front - of items with lower \c z values. The default \c z value is \c 0. - - \code - Rectangle{ - id: labelList - ... - z: 1 - Row{ - anchors.centerIn: parent - spacing:40 - Button{ - label: "File" - id: fileButton - ... - onButtonClick: menuListView.currentIndex = 0 - } - Button{ - id: editButton - label: "Edit" - ... - onButtonClick: menuListView.currentIndex = 1 - } - } - } - \endcode - - The menu bar we just created can be flicked to access the menus or by clicking - on the menu names at the top. Switching menu screens feel intuitive and responsive. - - \image qml-texteditor2_menubar.png - - */ - - /*! - \page qml-textEditor3.html - \title Building a Text Editor - - \section1 Declaring a TextArea - - Our text editor is not a text editor if it didn't contain an editable text area. - QML's \l {TextEdit}{TextEdit} element allows the declaration of a multi-line - editable text area. \l {TextEdit}{TextEdit} is different from a \l {Text}{Text} - element, which doesn't allow the user to directly edit the text. - - \code - TextEdit{ - id: textEditor - anchors.fill:parent - width:parent.width; height:parent.height - color:"midnightblue" - focus: true - - wrapMode: TextEdit.Wrap - - onCursorRectangleChanged: flickArea.ensureVisible(cursorRectangle) - } - \endcode - - The editor has its font color property set and set to wrap the text. The - \c TextEdit area is inside a flickable area that will scroll the text if the - text cursor is outside the visible area. The function \c ensureVisible() will - check if the cursor rectangle is outside the visible boundaries and move the - text area accordingly. QML uses Javascript syntax for its scripts, and as previously - mentioned, Javascript files can be imported and used within a QML file. - - \code - function ensureVisible(r){ - if (contentX >= r.x) - contentX = r.x; - else if (contentX+width <= r.x+r.width) - contentX = r.x+r.width-width; - if (contentY >= r.y) - contentY = r.y; - else if (contentY+height <= r.y+r.height) - contentY = r.y+r.height-height; - } - \endcode - - \section1 Combining Components for the Text Editor - - We are now ready to create the layout of our text editor using QML. The text - editor has two components, the menu bar we created and the text area. QML allows - us to reuse components, therefore making our code simpler, by importing components - and customizing when necessary. Our text editor splits the window into two; - one-third of the screen is dedicated to the menu bar and two-thirds of the screen - displays the text area. The menu bar is displayed in front of any other elements. - - \code - Rectangle{ - - id: screen - width: 1000; height: 1000 - - //the screen is partitioned into the MenuBar and TextArea. 1/3 of the screen is assigned to the MenuBar - property int partition: height/3 - - MenuBar{ - id:menuBar - height: partition - width:parent.width - z: 1 - } - - TextArea{ - id:textArea - anchors.bottom:parent.bottom - y: partition - color: "white" - height: partition*2 - width:parent.width - } - } - \endcode - - By importing reusable components, our \c TextEditor code looks much simpler. - We can then customize the main application, without worrying about properties - that already have defined behaviors. Using this approach, application layouts - and UI components can be created easily. - - \image qml-texteditor3_texteditor.png - - */ - - /*! - \page qml-textEditor4 - \title Decorating the Text Editor - \section1 Implementing a Drawer Interface - - Our text editor looks simple and we need to decorate it. Using QML, we can declare - transitions and animate our text editor. Our menu bar is occupying one-third of the - screen and it would be nice to have it only appear when we want it. - - We can add a drawer interface, that will contract or expand the menu bar when clicked. - In our implementation, we have a thin rectangle that responds to mouse clicks. The - \c drawer, as well as the application, has two sates: the "drawer is open" state and - the "drawer is closed" state. The \c drawer item is a strip of rectangle with a small - height. There is a nested \l {Image}{Image} element declaring that an arrow icon will - be centered inside the drawer. The drawer assigns a state to the whole application, - with the identifier \c screen, whenever a user clicks the mouse area. - - \code - Rectangle{ - id:drawer - height:15 - - Image{ - id: arrowIcon - source: "images/arrow.png" - anchors.horizontalCenter: parent.horizontalCenter - } - - MouseArea{ - id: drawerMouseArea - anchors.fill:parent - onClicked:{ - if (screen.state == "DRAWER_CLOSED"){ - screen.state = "DRAWER_OPEN" - } - else if (screen.state == "DRAWER_OPEN"){ - screen.state = "DRAWER_CLOSED" - } - } - ... - } - } - \endcode - - A state is simply a collection of configurations and it is declared in a - \l{State}{State} element. A list of states can be listed and bound to the - \c states property. In our application, the two states are called - \c DRAWER_CLOSED and \c DRAWER_OPEN. Item configurations are declared in - \l {PropertyChanges}{PropertyChanges} elements. In the \c DRAWER_OPEN state, - there are four items that will receive property changes. The first target, - \c menuBar, will change its \c y property to \c 0. Similarly, the \c textArea - will lower to a new position when the state is \c DRAWER_OPEN. The \c textArea, - the \c drawer, and the drawer's icon will undergo property changes to meet the - current state. - - \code - - states:[ - State{ - name: "DRAWER_OPEN" - PropertyChanges { target: menuBar; y:0} - PropertyChanges { target: textArea; y: partition + drawer.height} - PropertyChanges { target: drawer; y: partition} - PropertyChanges { target: arrowIcon; rotation: 180} - }, - State{ - name: "DRAWER_CLOSED" - PropertyChanges { target: menuBar; y:-partition} - PropertyChanges { target: textArea; y: drawer.height; height: screen.height - drawer.height} - PropertyChanges { target: drawer; y: 0} - PropertyChanges { target: arrowIcon; rotation: 0} - } - - ] - - \endcode - - State changes are abrupt and needs smoother transitions. Transitions between states - are defined using the \l {Transition}{Transition} element, which can then bind to - the item's \c transitions property. Our text editor has a state transition whenever - the state changes to either \c DRAWER_OPEN or \c DRAWER_CLOSED. Importantly, the - transition needs a \c from and a \c to state but for our transitions, we can use - the wild card \c * symbol to denote that the transition applies to all state changes. - - During transitions, we can assign animations to the property changes. Our - \c menuBar switches position from \c {y:0} to \c {y:-partition} and we can animate - this transition using the \l {NumberAnimation}{NumberAnimation} element. We declare - that the targets' properties will animate for a certain duration of time and using - a certain easing curve. An easing curve controls the animation rates and - interpolation behavior during state transitions. The easing curve we chose is - \l {PropertyAnimation::easing.type}{Easing.OutQuint}, which slows the movement near - the end of the animation. Pleae read \l {qdeclarativeanimation.html}{QML's Animation} - article. - - \code - transitions: [ - Transition{ - to: "*" - NumberAnimation { target: textArea; properties: "y, height"; duration: 100; easing.type: Easing.OutQuint } - NumberAnimation { target: menuBar; properties: "y"; duration: 100;easing.type: Easing.OutQuint } - NumberAnimation { target: drawer; properties: "y"; duration: 100;easing.type: Easing.OutQuint } - } - ] - \endcode - - Another way of animating property changes is by declaring a \l {Behavior}{Behavior} - element. A transition only works during state changes and \c Behavior can set an - animation for a general property change. In the text editor, the arrow has a - \c NumberAnimation animating its \c rotation property whenever the property changes. - - \code - In TextEditor.qml: - - Behavior{ - NumberAnimation{property: "rotation";easing.type: Easing.OutExpo } - } - \endcode - - Going back to our components with knowledge of states and animations, we can improve - the appearances of the components. In \c Button.qml, we can add \c color and \c scale - property changes when the button is clicked. Color types are animated using - \l {ColorAnimation}{ColorAnimation} and numbers are animated using - \l {NumberAnimation}{NumberAnimation}. The \c {on propertyName} syntax displayed below - is helpful when targeting a single property. - - \code - In Button.qml: - ... - - color: buttonMouseArea.pressed ? Qt.darker(buttonColor, 1.5) : buttonColor - Behavior on color { ColorAnimation{ duration: 55} } - - scale: buttonMouseArea.pressed ? 1.1 : 1.00 - Behavior on scale { NumberAnimation{ duration: 55} } - \endcode - - Additionally, we can enhance the appearances of our QML components by adding color - effects such as gradients and opacity effects. Declaring a \l {Gradient}{Gradient} - element will override the \c color property of the element. You may declare a color - in the gradient using the \l {GradientStop}{GradientStop} element. The gradient is - positioned using a scale, between \c 0.0 and \c 1.0. - - \code - In MenuBar.qml - gradient: Gradient { - GradientStop { position: 0.0; color: "#8C8F8C" } - GradientStop { position: 0.17; color: "#6A6D6A" } - GradientStop { position: 0.98;color: "#3F3F3F" } - GradientStop { position: 1.0; color: "#0e1B20" } - } - \endcode - - This gradient is used by the menu bar to display a gradient simulating depth. - The first color starts at \c 0.0 and the last color is at \c 1.0. - - - \section2 Where to Go from Here - - We are finished building the user interface of a very simple text editor. - Going forward, the user interface is complete, and we can implement the - application logic using regular Qt and C++. QML works nicely as a prototyping - tool, separating the application logic away from the UI design. - - \image qml-texteditor4_texteditor.png - - \section1 Extending QML using Qt C++ - - Now that we have our text editor layout, we may now implement the text editor - functionalities in C++. Using QML with C++ enables us to create our application - logic using Qt. We can create a QML context in a C++ application using the - \l {Using QML in C++ Applications}{Qt's Declarative} classes and display the QML - elements using a Graphics Scene. Alternatively, we can export our C++ code into - a plugin that the \l {QML Viewer}{qmlviewer} tool can read. For our application, - we shall implement the load and save functions in C++ and export it as a plugin. - This way, we only need to load the QML file directly instead of running an executable. - - \section2 Exposing C++ Classes to QML - - We will be implementing file loading and saving using Qt and C++. C++ classes - and functions can be used in QML by registering them. The class also needs to be - compiled as a Qt plugin and the QML file will need to know where the plugin is located. - - For our application, we need to create the following items: - \list 1 - \o \c Directory class that will handle directory related operations - \o \c File class which is a QObject, simulating the list of files in a directory - \o plugin class that will register the class to the QML context - \o Qt project file that will compile the plugin - \o A \c qmldir file telling the qmlviewer tool where to find the plugin - \endlist - - \section2 Building a Qt Plugin - - To build a plugin, we need to set the following in a Qt project file. First, - the necessary sources, headers, and Qt modules need to be added into our - project file. All the C++ code and project files are in the \c filedialog - directory. - - \code - In cppPlugins.pro: - - TEMPLATE = lib - CONFIG += qt plugin - QT += declarative - - DESTDIR += ../plugins - OBJECTS_DIR = tmp - MOC_DIR = tmp - - TARGET = FileDialog - - HEADERS += directory.h \ - file.h \ - dialogPlugin.h - - SOURCES += directory.cpp \ - file.cpp \ - dialogPlugin.cpp - \endcode - - In particular, we compile Qt with the \c declarative module and configure it as a - \c plugin, needing a \c lib template. We shall put the compiled plugin into the - parent's \c plugins directory. - - - \section2 Registering a Class into QML - - \code - In dialogPlugin.h: - - #include <QtDeclarative/QDeclarativeExtensionPlugin> - - class DialogPlugin : public QDeclarativeExtensionPlugin - { - Q_OBJECT - - public: - void registerTypes(const char *uri); - - }; - - \endcode - Our plugin class, \c DialogPlugin is a subclass of \l {QDeclarativeExtensionPlugin}{QDeclarativeExtensionPlugin}. We need to implement the inherited function, \l {QDeclarativeExtensionPlugin::registerTypes}{registerTypes}. The \c dialogPlugin.cpp file looks like this: - - \code - DialogPlugin.cpp: - - #include "dialogPlugin.h" - #include "directory.h" - #include "file.h" - #include <QtDeclarative/qdeclarative.h> - - void DialogPlugin::registerTypes(const char *uri){ - - qmlRegisterType<Directory>(uri, 1, 0, "Directory"); - qmlRegisterType<File>(uri, 1, 0,"File"); - } - - Q_EXPORT_PLUGIN2(FileDialog, DialogPlugin); - \endcode - - The \l {QDeclarativeExtensionPlugin::registerTypes}{registerTypes} - function registers our File and Directory classes into QML. This function - needs the class name for its template, a major version number, a minor version - number, and a name for our classes. - - We need to export the plugin using the \l {Q_EXPORT_PLUGIN2}{Q_EXPORT_PLUGIN2} - macro. Note that in our \c dialogPlugin.h file, we have the \l {Q_OBJECT}{Q_OBJECT} - macro at the top of our class. As well, we need to run \c qmake on the project - file to generate the necessary meta-object code. - - - \section2 Creating QML Properties in a C++ class - - We can create QML elements and properties using C++ and - \l {The Meta-Object System}{Qt's Meta-Object System}. We can implement - properties using slots and signals, making Qt aware of these properties. - These properties can then be used in QML. - - For the text editor, we need to be able to load and save files. Typically, - these features are contained in a file dialog. Fortunately, we can use - \l {QDir}{QDir}, \l {QFile}{QFile}, and \l {QTextStream}{QTextStream} to - implement directory reading and input/output streams. - - \code - class Directory : public QObject{ - - Q_OBJECT - - Q_PROPERTY(int filesCount READ filesCount CONSTANT) - Q_PROPERTY(QString filename READ filename WRITE setFilename NOTIFY filenameChanged) - Q_PROPERTY(QString fileContent READ fileContent WRITE setFileContent NOTIFY fileContentChanged) - Q_PROPERTY(QDeclarativeListProperty<File> files READ files CONSTANT ) - - ... - \endcode - - The \c Directory class uses Qt's Meta-Object System to register properties it - needs to accomplish file handling. The \c Directory class is exported as a plugin - and is useable in QML as the \c Directory element. Each of the listed properties - using the \l {Q_PROPERTY()}{Q_PROPERTY} macro is a QML property. - - The \l {Q_PROPERTY()} {Q_PROPERTY} declares a property as well as its read and - write functions into Qt's Meta-Object System. For example, the \c filename - property, of type \l {QString}{QString}, is readable using the \c filename() - function and writable using the function \c setFilename(). Additionally, there - is a signal associated to the filename property called \c filenameChanged(), - which is emitted whenever the property changes. The read and write functions - are declared as \c public in the header file. - - Similarly, we have the other properties declared according to their uses. The - \c filesCount property indicates the number of files in a directory. The filename - property is set to the currently selected file's name and the loaded/saved file - content is stored in \c fileContent property. - - \code - Q_PROPERTY(QDeclarativeListProperty<File> files READ files CONSTANT ) - \endcode - - The \c files list property is a list of all the filtered files in a directory. - The \c Directory class is implemented to filter out invalid text files; only - files with a \c .txt extension are valid. Further, \l {QLists}{QLists} can be - used in QML files by declaring them as a \c QDeclarativeListProperty in C++. - The templated object needs to inherit from a \l {QObject}{QObject}, therefore, - the \c File class must also inherit from \c QObject. In the \c Directory class, - the list of \c File objects is stored in a \c QList called \c m_fileList. - - \code - class File : public QObject{ - - Q_OBJECT - Q_PROPERTY(QString name READ name WRITE setName NOTIFY nameChanged) - - ... - }; - \endcode - - The properties can then be used in QML as part of the \c Directory element's - properties. Note that we do not have to create an identifier \c id property - in our C++ code. - - \code - Directory{ - id: directory - - filesCount - filename - fileContent - files - - files[0].name - } - - \endcode - - Because QML uses Javascript's syntax and structure, we can iterate through - the list of files and retrieve its properties. To retrieve the first file's - name property, we can call \c { files[0].name }. - - Regular C++ functions are also accessible from QML. The file loading and saving - functions are implemented in C++ and declared using the - \l {Q_INVOKABLE}{Q_INVOKABLE} macro. Alternatively, we can declare the functions - as a \c slot and the functions will be accessible from QML. - - \code - In Directory.h: - - Q_INVOKABLE void saveFile(); - Q_INVOKABLE void loadFile(); - \endcode - - The \c Directory class also has to notify other objects whenever the directory - contents change. This feature is performed using a \c signal. As previously - mentioned, QML signals have a corresponding handler with their names prepended - with \c on. The signal is called \c directoryChanged and it is emitted whenever - there is a directory refresh. The refresh simply reloads the directory contents - and updates the list of valid files in the directory. QML items can then be - notified by attaching an action to the \c onDirectoryChanged signal handler. - - The \c list properties need to be explored further. This is because list - properties use callbacks to access and modify the list contents. The list - property is of type \c QDeclarativeListProperty<File>. Whenever the list - is accessed, the accessor function needs to return a - \c QDeclarativeListProperty<File>. The template type, \c File, needs to be a - \c QObject derivative. Further, to create the - \l {QDeclarativeListProperty}{QDeclarativeListProperty}, the list's accessor - and modifiers need to be passed to the consructor as function pointers. The list, - a \c QList in our case, also needs to be a list of \c File pointers. - - The constructor of \l {QDeclarativeListProperty}{QDeclarativeListProperty} - constructor and the \c Directory implementation: - \code - QDeclarativeListProperty ( QObject * object, void * data, AppendFunction append, CountFunction count = 0, AtFunction at = 0, ClearFunction clear = 0 ) - QDeclarativeListProperty<File>( this, &m_fileList, &appendFiles, &filesSize, &fileAt, &clearFilesPtr ); - \endcode - - The constructor passes pointers to functions that will append the list, count - the list, retrieve the item using an index, and empty the list. Only the append - function is mandatory. Note that the function pointers must match the definition - of \l {QDeclarativeListProperty::AppendFunction}{AppendFunction}, - \l {QDeclarativeListProperty::CountFunction}{CountFunction}, - \l {QDeclarativeListProperty::AtFunction}{AtFunction}, or - \l {QDeclarativeListProperty::ClearFunction}{ClearFunction}. - - \code - void appendFiles(QDeclarativeListProperty<File> * property, File * file) - File* fileAt(QDeclarativeListProperty<File> * property, int index) - int filesSize(QDeclarativeListProperty<File> * property) - void clearFilesPtr(QDeclarativeListProperty<File> *property) - \endcode - - To simplify our file dialog, the \c Directory class filters out invalid text - files, which are files that do not have a \c .txt extension. If a file name - doesn't have the \c .txt extension, then it won't be seen in our file dialog. - Also, the implementation makes sure that saved files have a \c .txt extension in - the file name. \c Directory uses \l {QTextStream}{QTextStream} to read the file - and to output the file contents to a file. - - With our \c Directory element, we can retrieve the files as a list, know how many - text files is in the application directory, get the file's name and content as a - string, and be notified whenever there are changes in the directory contents. - - To build the plugin, run \c qmake on the \c cppPlugins.pro project file, then run - \c make to build and transfer the plugin to the \c plugins directory. - - - \section2 Importing a Plugin in QML - - The qmlviewer tool imports files that are in the same directory as the - application. We can also create a \c qmldir file containing the locations of - QML files we wish to import. The \c qmldir file can also store locations of - plugins and other resources. - - \code - In qmldir: - - Button ./Button.qml - FileDialog ./FileDialog.qml - TextArea ./TextArea.qml - TextEditor ./TextEditor.qml - EditMenu ./EditMenu.qml - - plugin FileDialog plugins - \endcode - - The plugin we just created is called \c FileDialog, as indicated by the - \c TARGET field in the project file. The compiled plugin is in the \c plugins directory. - - - \section2 Integrating a File Dialog into the File Menu - - Our \c FileMenu needs to display the \c FileDialog element, containing a list of - the text files in a directory thus allowing the user to select the file by - clicking on the list. We also need to assign the save, load, and new buttons - to their respective actions. The FileMenu contains an editable text input to - allow the user to type a file name using the keyboard. - - The \c Directory element is used in the \c FileMenu.qml file and it notifies the - \c FileDialog element that the directory refreshed its contents. This notification - is performed in the signal handler, \c onDirectoryChanged. - - \code - In FileMenu.qml: - - Directory{ - id:directory - filename: textInput.text - onDirectoryChanged: fileDialog.notifyRefresh() - } - \endcode - - Keeping with the simplicity of our application, the file dialog will always be - visible and will not display invalid text files, which do not have a \c .txt - extension to their filenames. - - \code - In FileDialog.qml: - - signal notifyRefresh() - onNotifyRefresh: dirView.model = directory.files - \endcode - - The \c FileDialog element will display the contents of a directory by reading its - list property called \c files. The files are used as the model of a - \l {GridView}{GridView} element, which displays data items in a grid according - to a delegate. The delegate handles the appearance of the model and our file - dialog will simply create a grid with text centered in the middle. Clicking on - the file name will result in the appearance of a rectangle to highlight the file - name. The \c FileDialog is notified whenever the \c notifyRefresh signal is emitted, - reloading the files in the directory. - - \code - In FileMenu.qml: - - Button{ - id: newButton - label: "New" - onButtonClick:{ - textArea.textContent = "" - } - } - Button{ - id: loadButton - label: "Load" - onButtonClick:{ - directory.filename = textInput.text - directory.loadFile() - textArea.textContent = directory.fileContent - } - } - Button{ - id: saveButton - label: "Save" - onButtonClick:{ - directory.fileContent = textArea.textContent - directory.filename = textInput.text - directory.saveFile() - } - } - Button{ - id: exitButton - label: "Exit" - onButtonClick:{ - Qt.quit() - } - } - \endcode - - Our \c FileMenu can now connect to their respective actions. The \c saveButton - will transfer the text from the \c TextEdit onto the directory's \c fileContent - property, then copy its file name from the editable text input. Finally, the button - calls the \c saveFile() function, saving the file. The \c sloadButton has a similar - execution. Also, the \c New action will empty the contents of the \c TextEdit. - - Further, the \c EditMenu buttons are connected to the \c TextEdit functions to copy, - paste, and select all the text in the text editor. - - \image qml-texteditor5_filemenu.png - - \section1 Text Editor Completion - - \image qml-texteditor5_newfile.png - - The application can function as a simple text editor, able to accept text - and save the text into a file. The text editor can also load from a file and - perform text manipulation. - - -*/
\ No newline at end of file + \page gettingstartedqml.html + \title Getting Started Programming with QML + \ingroup gettingStarted + + Welcome to the world of QML, the declarative UI language. In this Getting + Started guide, we will create a simple text editor application using QML. + After reading this guide, you should be ready to develop your own applications + using QML and Qt C++. + + \section1 QML to Build User Interfaces + + The application we are building is a simple text editor that will load, save, + and perform some text manipulation. This guide will consist of two parts. The + first part will involve designing the application layout and behaviors using + declarative language in QML. For the second part, file loading and saving will + be implemented using Qt C++. Using + \l {The Meta-Object System}{Qt's Meta-Object System}, we can expose C++ functions + as properties that QML elements can use. Utilizing QML and Qt C++, we can + efficiently decouple the interface logic from the application logic. + + \image qml-texteditor5_editmenu.png + + To run the QML example code, merely provide the included \l{QML Viewer}{qmlviewer} + tool with the QML file as the argument. The C++ portion of this tutorial assumes + that the reader possesses basic knowledge of Qt's compilation procedures. + + Tutorial chapters: + \list 1 + \o \l {Defining a Button and a Menu}{Defining a Button and a Menu} + \o \l {Implementing a Menu Bar}{Implementing a Menu Bar} + \o \l {Building a Text Editor}{Building a Text Editor} + \o \l {Decorating the Text Editor}{Decorating the Text Editor} + \o \l {Extending QML using Qt C++}{Extending QML using Qt C++} + \endlist + + \section1 Defining a Button and a Menu + + \section2 Basic Component - a Button + + We start our text editor by building a button. Functionally, a button has a mouse + sensitive area and a label. Buttons perform actions when a user presses the button. + + In QML, the basic visual item is the \l {Rectangle}{Rectangle} element. The + \c Rectangle element has properties to control the element's appearance and location. + + \code + import Qt 4.7 + Rectangle { + id: simplebutton + color: "grey" + width: 150; height: 75 + + Text{ + id: buttonLabel + anchors.centerIn: parent + text: "button label" + } + } + \endcode + + First, the \c { import Qt 4.7 } allows the qmlviewer tool to import the QML elements + we will later use. This line must exist for every QML file. Notice that the version + of Qt modules is included in the import statement. + + This simple rectangle has a unique identifier, \c simplebutton, which is bound to the + id property. The \c Rectangle element's properties are bound to values by listing the + property, followed by a colon, then the value. In the code sample, the color \c grey + is bound to the the Rectangle's \c color property. Similarly, we bind the \c width + and \c height of the Rectangle. + + The \l {Text}{Text} element is a non-editable text field. We name this \c Text element + \c buttonLabel. To set the string content of the Text field, we bind a value to the + \c text property. The label is contained within the Rectangle and in order to center + it in the middle, we assign the \c anchors of the Text element to its parent, which + is called \c simplebutton. Anchors may bind to other items' anchors, allowing layout + assignments simpler. + + We shall save this code as \c SimpleButton.qml. Running qmlviewer with the file as the + argument will display the grey rectangle with a text label. + + \image qml-texteditor1_simplebutton.png + + To implement the button click functionality, we can use QML's event handling. QML's event + handling is very similar to \l {Signals & Slots}{Qt's signal and slot} mechanism. Signals + are emitted and the connected slot is called. + + \code + Rectangle{ + id:simplebutton + ... + + MouseArea{ + id: buttonMouseArea + + anchors.fill: parent //anchor all sides of the mouse area to the rectangle's anchors + //onClicked handles valid mouse button clicks + onClicked: console.log(buttonLabel.text + " clicked" ) + } + } + \endcode + + We include a \l{MouseArea} element in our simplebutton. \c MouseArea elements describe + the interactive area where mouse movements are detected. For our button, we anchor the + whole MouseArea to its parent, which is \c simplebutton. The \c anchors.fill syntax is + one way of accessing a specific property called \c fill inside a group of properties + called \c anchors. QML uses \l {Anchor-based Layout in QML}{anchor based layouts} where + items can anchor to another item, creating robust layouts. + + The \c MouseArea has many signal handlers that are called during mouse movements within + the specfied \c MouseArea boundaries. One of them is \c onClicked and it is called + whenever the acceptable mouse button is clicked, the left click being the default. We + can bind actions to the onClicked handler. In our example, \c console.log() outputs text + whenever the mouse area is clicked. The function \c console.log() is a useful tool for + debugging purposes and for outputting text. + + The code in \c SimpleButton.qml is sufficient to display a button on the screen and + output text whenever it is clicked with a mouse. + + \code + Rectangle { + id:Button + ... + + property color buttonColor: "lightblue" + property color onHoverColor: "gold" + property color borderColor: "white" + + signal buttonClick() + onButtonClick: { + console.log(buttonLabel.text + " clicked" ) + } + + MouseArea{ + onClicked: buttonClick() + hoverEnabled: true + onEntered: parent.border.color = onHoverColor + onExited: parent.border.color = borderColor + } + + //determines the color of the button by using the conditional operator + color: buttonMouseArea.pressed ? Qt.darker(buttonColor, 1.5) : buttonColor + } + \endcode + + A fully functioning button is in \c Button.qml. The code snippets in this article + have some code omitted, denoted by ellipses because they were either introduced + earlier in the previous sections or irrelevant to the current code discussion. + + Custom properties are declared using the \c {property type name} syntax. In the + code, the property \c buttonColor, of type \c color, is declared and bound to + the value \c{"lightblue"}. The \c buttonColor is later used in a conditional + operation to determine the buttons's fill color. Note that property value + assignment is possible using the \c= equals sign, in addition to value binding + using the \c : colon character. Custom properties allow internal items to be + accessible outside of the Rectangle's scope. There are basic + \l{QML Basic Types}{QML types} such as \c int, \c string, \c real, as well as + a type called \c variant. + + By binding the \c onEntered and \c onExited signal handlers to colors, the + button's border will turn yellow when the mouse hovers above the button and + reverts the color when the mouse exits the mouse area. + + A \c buttonClick() signal is declared in \c Button.qml by placing the \c signal + keyword in front of the signal name. All signals have their handlers automatically + created, their names starting with \c on. As a result, the \c onButtonClick is + \c buttonClick's handler. The \c onButtonClick is then assigned an action to + perform. In our button example, the \c onClicked mouse handler will simply call + \c onButtonClick, which displays a text. The \c onButtonClick enables outside + objects to access the \c {Button}'s mouse area easily. For example, items may + have more than one \c MouseArea declarations and a \c buttonClick signal can + make the distinction between the several \c MouseArea signal handlers better. + + We now have the basic knowledge to implement items in QML that can handle + basic mouse movements. We created a \c Text label inside a \c Rectangle, + customized its properties, and implemented behaviors that respond to mouse + movements. This idea of creating elements within elements is repeated + throughout the text editor application. + + This button is not useful unless used as a component to perform an action. + In the next section, we will soon create a menu containing several of these + buttons. + + \image qml-texteditor1_button.png + + \section2 Creating a Menu Page + + Up to this stage, we covered how to create elements and assign behaviors inside + a single QML file. In this section, we will cover how to import QML elements and how + to reuse some of the created components to build other components. + + Menus display the contents of a list, each item having the ability to perform an action. + In QML, we can create a menu in several ways. First, we will create a menu containing + buttons which will eventually perform different actions. The menu code is in + \c FileMenu.qml. + + \code + import Qt 4.7 \\import the main Qt QML module + import "folderName" \\import the contents of the folder + import "Button.qml" \\import a QML file + import "NewButton.qml" as ButtonModule \\import a QML file and give it a name + import "script.js" as Script \\import a Javascript file and name it as Script + \endcode + + To use the \c Button element in \c FileMenu.qml, we need to import \c Button.qml. + The syntax shown above, shows how to use the \c import keyword. However, the + \c {import Button.qml} is not necessary; qmlviewer will import all the contents + of the current directory. We can directly create a \c Button element by declaring + \c Button{}, similar to a \c Rectangle{} declaration. + + \code + In FileMenu.qml: + + Row{ + anchors.centerIn: parent + spacing: parent.width/6 + + Button{ + id: loadButton + buttonColor: "lightgrey" + label: "Load" + } + Button{ + buttonColor: "grey" + id: saveButton + label: "Save" + } + Button{ + id: exitButton + label: "Exit" + buttonColor: "darkgrey" + + onButtonClick: Qt.quit() + } + } + \endcode + + In \c FileMenu.qml, we declare three \c Button elements. They are declared + inside a \l {Row}{Row} element, a positioner that will position its children + along a vertical row. The \c Button declaration resides in Button.qml, + which is the same as the \c Button.qml we used in the previous section. + New property bindings can be declared within the newly created buttons, + effectively overwriting the properties set in \c Button.qml. The button + called \c exitButton will quit and close the window when it is clicked. + Note that the signal handler \c onButtonClick in \c Button.qml will be + called in addition to the \c onButtonClick handler in \c exitButton. + + \image qml-texteditor1_filemenu.png + + The \c Row declaration is declared in a \c Rectangle, creating a rectangle + container for the row of buttons. This additional rectangle creates an indirect + way of organizing the row of buttons inside a menu. + + The declaration of the edit menu is very similar at this stage. The menu has + buttons that have the labels: \c Copy, \c Paste, and \c {Select All}. + + \image qml-texteditor1_editmenu.png + + Armed with our knowledge of importing and customizing previously made + components, we may now combine these menu pages to create a menu bar, + consisting of buttons to select the menu, and look at how we may structure + data using QML. + + \section1 Implementing a Menu Bar + + Our text editor application will need a way to display menus using a menu bar. + The menu bar will switch the different menus and the user can choose which menu + to display. Menu switching implies that the menus need more structure than + merely displaying them in a row. QML uses models and views to structure data + and display the structured data. + + \section2 Using Data Models and Views + + QML has different \l {Data Models}{data views} that display + \l {Data Models}{data models}. Our menu bar will display the menus in a list, + with a header that displays a row of menu names. The list of menus are declared + inside a \c VisualItemModel. The \l{VisualItemModel}{\c VisualItemModel} + element contains items that already have views such as \c Rectangle elements + and imported UI elements. Other model types such as the \l{ListModel}{\c ListModel} + element need a delegate to display their data. + + We declare two visual items in the \c menuListModel, the \c FileMenu and the + \c EditMenu. We customize the two menus and display them using a + \l {ListView}{ListView}. The \c MenuBar.qml file contains the QML declarations + and a simple edit menu is defined in \c EditMenu.qml. + + \code + VisualItemModel{ + id: menuListModel + FileMenu{ + width: menuListView.width + height: menuBar.height + color: fileColor + } + EditMenu{ + color: editColor + width: menuListView.width + height: menuBar.height + } + } + \endcode + + The \l {ListView}{ListView} element will display a model according to a delegate. + The delegate may declare the model items to display in a \c Row element or display + the items in a grid. Our \c menuListModel already has visible items, therefore, + we do not need to declare a delegate. + + \code + ListView{ + id: menuListView + + //Anchors are set to react to window anchors + anchors.fill:parent + anchors.bottom: parent.bottom + width:parent.width + height: parent.height + + //the model contains the data + model: menuListModel + + //control the movement of the menu switching + snapMode: ListView.SnapOneItem + orientation: ListView.Horizontal + boundsBehavior: Flickable.StopAtBounds + flickDeceleration: 5000 + highlightFollowsCurrentItem: true + highlightMoveDuration:240 + highlightRangeMode: ListView.StrictlyEnforceRange + } + \endcode + + Additionally, \c ListView inherits from \l{Flickable}{\c Flickable}, making + the list respond to mouse drags and other gestures. The last portion of the + code above sets \c Flickable properties to create the desired flicking movement + to our view. In particular,the property \c highlightMoveDuration changes the + duration of the flick transition. A higher \c highlightMoveDuration value + results in slower menu switching. + + The \c ListView maintains the model items through an \c index and each visual + item in the model is accessible through the \c index, in the order of the + declaration. Changing the \c currentIndex effectively changes the highlighted + item in the \c ListView. The header of our menu bar exemplify this effect. + There are two buttons in a row, both changing the current menu when clicked. + The \c fileButton changes the current menu to the file menu when clicked, + the \c index being \c 0 because \c FileMenu is declared first in the + \c menuListModel. Similarly, the \c editButton will change the current + menu to the \c EditMenu when clicked. + + The \c labelList rectangle has \c z value of \c 1, denoting that it is displayed + at the front of the menu bar. Items with higher \c z values are displayed in front + of items with lower \c z values. The default \c z value is \c 0. + + \code + Rectangle{ + id: labelList + ... + z: 1 + Row{ + anchors.centerIn: parent + spacing:40 + Button{ + label: "File" + id: fileButton + ... + onButtonClick: menuListView.currentIndex = 0 + } + Button{ + id: editButton + label: "Edit" + ... + onButtonClick: menuListView.currentIndex = 1 + } + } + } + \endcode + + The menu bar we just created can be flicked to access the menus or by clicking + on the menu names at the top. Switching menu screens feel intuitive and responsive. + + \image qml-texteditor2_menubar.png + + */ + + /*! + \page qml-textEditor3.html + \title Building a Text Editor + + \section1 Declaring a TextArea + + Our text editor is not a text editor if it didn't contain an editable text area. + QML's \l {TextEdit}{TextEdit} element allows the declaration of a multi-line + editable text area. \l {TextEdit}{TextEdit} is different from a \l {Text}{Text} + element, which doesn't allow the user to directly edit the text. + + \code + TextEdit{ + id: textEditor + anchors.fill:parent + width:parent.width; height:parent.height + color:"midnightblue" + focus: true + + wrapMode: TextEdit.Wrap + + onCursorRectangleChanged: flickArea.ensureVisible(cursorRectangle) + } + \endcode + + The editor has its font color property set and set to wrap the text. The + \c TextEdit area is inside a flickable area that will scroll the text if the + text cursor is outside the visible area. The function \c ensureVisible() will + check if the cursor rectangle is outside the visible boundaries and move the + text area accordingly. QML uses Javascript syntax for its scripts, and as previously + mentioned, Javascript files can be imported and used within a QML file. + + \code + function ensureVisible(r){ + if (contentX >= r.x) + contentX = r.x; + else if (contentX+width <= r.x+r.width) + contentX = r.x+r.width-width; + if (contentY >= r.y) + contentY = r.y; + else if (contentY+height <= r.y+r.height) + contentY = r.y+r.height-height; + } + \endcode + + \section1 Combining Components for the Text Editor + + We are now ready to create the layout of our text editor using QML. The text + editor has two components, the menu bar we created and the text area. QML allows + us to reuse components, therefore making our code simpler, by importing components + and customizing when necessary. Our text editor splits the window into two; + one-third of the screen is dedicated to the menu bar and two-thirds of the screen + displays the text area. The menu bar is displayed in front of any other elements. + + \code + Rectangle{ + + id: screen + width: 1000; height: 1000 + + //the screen is partitioned into the MenuBar and TextArea. 1/3 of the screen is assigned to the MenuBar + property int partition: height/3 + + MenuBar{ + id:menuBar + height: partition + width:parent.width + z: 1 + } + + TextArea{ + id:textArea + anchors.bottom:parent.bottom + y: partition + color: "white" + height: partition*2 + width:parent.width + } + } + \endcode + + By importing reusable components, our \c TextEditor code looks much simpler. + We can then customize the main application, without worrying about properties + that already have defined behaviors. Using this approach, application layouts + and UI components can be created easily. + + \image qml-texteditor3_texteditor.png + + */ + + /*! + \page qml-textEditor4 + \title Decorating the Text Editor + \section1 Implementing a Drawer Interface + + Our text editor looks simple and we need to decorate it. Using QML, we can declare + transitions and animate our text editor. Our menu bar is occupying one-third of the + screen and it would be nice to have it only appear when we want it. + + We can add a drawer interface, that will contract or expand the menu bar when clicked. + In our implementation, we have a thin rectangle that responds to mouse clicks. The + \c drawer, as well as the application, has two sates: the "drawer is open" state and + the "drawer is closed" state. The \c drawer item is a strip of rectangle with a small + height. There is a nested \l {Image}{Image} element declaring that an arrow icon will + be centered inside the drawer. The drawer assigns a state to the whole application, + with the identifier \c screen, whenever a user clicks the mouse area. + + \code + Rectangle{ + id:drawer + height:15 + + Image{ + id: arrowIcon + source: "images/arrow.png" + anchors.horizontalCenter: parent.horizontalCenter + } + + MouseArea{ + id: drawerMouseArea + anchors.fill:parent + onClicked:{ + if (screen.state == "DRAWER_CLOSED"){ + screen.state = "DRAWER_OPEN" + } + else if (screen.state == "DRAWER_OPEN"){ + screen.state = "DRAWER_CLOSED" + } + } + ... + } + } + \endcode + + A state is simply a collection of configurations and it is declared in a + \l{State}{State} element. A list of states can be listed and bound to the + \c states property. In our application, the two states are called + \c DRAWER_CLOSED and \c DRAWER_OPEN. Item configurations are declared in + \l {PropertyChanges}{PropertyChanges} elements. In the \c DRAWER_OPEN state, + there are four items that will receive property changes. The first target, + \c menuBar, will change its \c y property to \c 0. Similarly, the \c textArea + will lower to a new position when the state is \c DRAWER_OPEN. The \c textArea, + the \c drawer, and the drawer's icon will undergo property changes to meet the + current state. + + \code + + states:[ + State{ + name: "DRAWER_OPEN" + PropertyChanges { target: menuBar; y:0} + PropertyChanges { target: textArea; y: partition + drawer.height} + PropertyChanges { target: drawer; y: partition} + PropertyChanges { target: arrowIcon; rotation: 180} + }, + State{ + name: "DRAWER_CLOSED" + PropertyChanges { target: menuBar; y:-partition} + PropertyChanges { target: textArea; y: drawer.height; height: screen.height - drawer.height} + PropertyChanges { target: drawer; y: 0} + PropertyChanges { target: arrowIcon; rotation: 0} + } + + ] + + \endcode + + State changes are abrupt and needs smoother transitions. Transitions between states + are defined using the \l {Transition}{Transition} element, which can then bind to + the item's \c transitions property. Our text editor has a state transition whenever + the state changes to either \c DRAWER_OPEN or \c DRAWER_CLOSED. Importantly, the + transition needs a \c from and a \c to state but for our transitions, we can use + the wild card \c * symbol to denote that the transition applies to all state changes. + + During transitions, we can assign animations to the property changes. Our + \c menuBar switches position from \c {y:0} to \c {y:-partition} and we can animate + this transition using the \l {NumberAnimation}{NumberAnimation} element. We declare + that the targets' properties will animate for a certain duration of time and using + a certain easing curve. An easing curve controls the animation rates and + interpolation behavior during state transitions. The easing curve we chose is + \l{PropertyAnimation::easing.type}{Easing.OutQuint}, which slows the movement near + the end of the animation. Pleae read \l {qdeclarativeanimation.html}{QML's Animation} + article. + + \code + transitions: [ + Transition{ + to: "*" + NumberAnimation { target: textArea; properties: "y, height"; duration: 100; easing.type: Easing.OutQuint } + NumberAnimation { target: menuBar; properties: "y"; duration: 100;easing.type: Easing.OutQuint } + NumberAnimation { target: drawer; properties: "y"; duration: 100;easing.type: Easing.OutQuint } + } + ] + \endcode + + Another way of animating property changes is by declaring a \l {Behavior}{Behavior} + element. A transition only works during state changes and \c Behavior can set an + animation for a general property change. In the text editor, the arrow has a + \c NumberAnimation animating its \c rotation property whenever the property changes. + + \code + In TextEditor.qml: + + Behavior{ + NumberAnimation{property: "rotation";easing.type: Easing.OutExpo } + } + \endcode + + Going back to our components with knowledge of states and animations, we can improve + the appearances of the components. In \c Button.qml, we can add \c color and \c scale + property changes when the button is clicked. Color types are animated using + \l {ColorAnimation}{ColorAnimation} and numbers are animated using + \l {NumberAnimation}{NumberAnimation}. The \c {on propertyName} syntax displayed below + is helpful when targeting a single property. + + \code + In Button.qml: + ... + + color: buttonMouseArea.pressed ? Qt.darker(buttonColor, 1.5) : buttonColor + Behavior on color { ColorAnimation{ duration: 55} } + + scale: buttonMouseArea.pressed ? 1.1 : 1.00 + Behavior on scale { NumberAnimation{ duration: 55} } + \endcode + + Additionally, we can enhance the appearances of our QML components by adding color + effects such as gradients and opacity effects. Declaring a \l {Gradient}{Gradient} + element will override the \c color property of the element. You may declare a color + in the gradient using the \l {GradientStop}{GradientStop} element. The gradient is + positioned using a scale, between \c 0.0 and \c 1.0. + + \code + In MenuBar.qml + gradient: Gradient { + GradientStop { position: 0.0; color: "#8C8F8C" } + GradientStop { position: 0.17; color: "#6A6D6A" } + GradientStop { position: 0.98;color: "#3F3F3F" } + GradientStop { position: 1.0; color: "#0e1B20" } + } + \endcode + + This gradient is used by the menu bar to display a gradient simulating depth. + The first color starts at \c 0.0 and the last color is at \c 1.0. + + + \section2 Where to Go from Here + + We are finished building the user interface of a very simple text editor. + Going forward, the user interface is complete, and we can implement the + application logic using regular Qt and C++. QML works nicely as a prototyping + tool, separating the application logic away from the UI design. + + \image qml-texteditor4_texteditor.png + + \section1 Extending QML using Qt C++ + + Now that we have our text editor layout, we may now implement the text editor + functionalities in C++. Using QML with C++ enables us to create our application + logic using Qt. We can create a QML context in a C++ application using the + \l {Using QML in C++ Applications}{Qt's Declarative} classes and display the QML + elements using a Graphics Scene. Alternatively, we can export our C++ code into + a plugin that the \l {QML Viewer}{qmlviewer} tool can read. For our application, + we shall implement the load and save functions in C++ and export it as a plugin. + This way, we only need to load the QML file directly instead of running an executable. + + \section2 Exposing C++ Classes to QML + + We will be implementing file loading and saving using Qt and C++. C++ classes + and functions can be used in QML by registering them. The class also needs to be + compiled as a Qt plugin and the QML file will need to know where the plugin is located. + + For our application, we need to create the following items: + \list 1 + \o \c Directory class that will handle directory related operations + \o \c File class which is a QObject, simulating the list of files in a directory + \o plugin class that will register the class to the QML context + \o Qt project file that will compile the plugin + \o A \c qmldir file telling the qmlviewer tool where to find the plugin + \endlist + + \section2 Building a Qt Plugin + + To build a plugin, we need to set the following in a Qt project file. First, + the necessary sources, headers, and Qt modules need to be added into our + project file. All the C++ code and project files are in the \c filedialog + directory. + + \code + In cppPlugins.pro: + + TEMPLATE = lib + CONFIG += qt plugin + QT += declarative + + DESTDIR += ../plugins + OBJECTS_DIR = tmp + MOC_DIR = tmp + + TARGET = FileDialog + + HEADERS += directory.h \ + file.h \ + dialogPlugin.h + + SOURCES += directory.cpp \ + file.cpp \ + dialogPlugin.cpp + \endcode + + In particular, we compile Qt with the \c declarative module and configure it as a + \c plugin, needing a \c lib template. We shall put the compiled plugin into the + parent's \c plugins directory. + + + \section2 Registering a Class into QML + + \code + In dialogPlugin.h: + + #include <QtDeclarative/QDeclarativeExtensionPlugin> + + class DialogPlugin : public QDeclarativeExtensionPlugin + { + Q_OBJECT + + public: + void registerTypes(const char *uri); + + }; + + \endcode + + Our plugin class, \c DialogPlugin is a subclass of \l{QDeclarativeExtensionPlugin}. + We need to implement the inherited function, \l {QDeclarativeExtensionPlugin::}{registerTypes()}. + The \c dialogPlugin.cpp file looks like this: + + \code + DialogPlugin.cpp: + + #include "dialogPlugin.h" + #include "directory.h" + #include "file.h" + #include <QtDeclarative/qdeclarative.h> + + void DialogPlugin::registerTypes(const char *uri){ + + qmlRegisterType<Directory>(uri, 1, 0, "Directory"); + qmlRegisterType<File>(uri, 1, 0,"File"); + } + + Q_EXPORT_PLUGIN2(FileDialog, DialogPlugin); + \endcode + + The \l{QDeclarativeExtensionPlugin::}{registerTypes()} function registers + our File and Directory classes into QML. This function needs the class name + for its template, a major version number, a minor version number, and a name + for our classes. + + We need to export the plugin using the \l {Q_EXPORT_PLUGIN2}{Q_EXPORT_PLUGIN2} + macro. Note that in our \c dialogPlugin.h file, we have the \l {Q_OBJECT}{Q_OBJECT} + macro at the top of our class. As well, we need to run \c qmake on the project + file to generate the necessary meta-object code. + + + \section2 Creating QML Properties in a C++ class + + We can create QML elements and properties using C++ and + \l {The Meta-Object System}{Qt's Meta-Object System}. We can implement + properties using slots and signals, making Qt aware of these properties. + These properties can then be used in QML. + + For the text editor, we need to be able to load and save files. Typically, + these features are contained in a file dialog. Fortunately, we can use + \l {QDir}{QDir}, \l {QFile}{QFile}, and \l {QTextStream}{QTextStream} to + implement directory reading and input/output streams. + + \code + class Directory : public QObject{ + + Q_OBJECT + + Q_PROPERTY(int filesCount READ filesCount CONSTANT) + Q_PROPERTY(QString filename READ filename WRITE setFilename NOTIFY filenameChanged) + Q_PROPERTY(QString fileContent READ fileContent WRITE setFileContent NOTIFY fileContentChanged) + Q_PROPERTY(QDeclarativeListProperty<File> files READ files CONSTANT ) + + ... + \endcode + + The \c Directory class uses Qt's Meta-Object System to register properties it + needs to accomplish file handling. The \c Directory class is exported as a plugin + and is useable in QML as the \c Directory element. Each of the listed properties + using the \l {Q_PROPERTY()}{Q_PROPERTY} macro is a QML property. + + The \l {Q_PROPERTY()} {Q_PROPERTY} declares a property as well as its read and + write functions into Qt's Meta-Object System. For example, the \c filename + property, of type \l {QString}{QString}, is readable using the \c filename() + function and writable using the function \c setFilename(). Additionally, there + is a signal associated to the filename property called \c filenameChanged(), + which is emitted whenever the property changes. The read and write functions + are declared as \c public in the header file. + + Similarly, we have the other properties declared according to their uses. The + \c filesCount property indicates the number of files in a directory. The filename + property is set to the currently selected file's name and the loaded/saved file + content is stored in \c fileContent property. + + \code + Q_PROPERTY(QDeclarativeListProperty<File> files READ files CONSTANT ) + \endcode + + The \c files list property is a list of all the filtered files in a directory. + The \c Directory class is implemented to filter out invalid text files; only + files with a \c .txt extension are valid. Further, \l {QLists}{QLists} can be + used in QML files by declaring them as a \c QDeclarativeListProperty in C++. + The templated object needs to inherit from a \l {QObject}{QObject}, therefore, + the \c File class must also inherit from \c QObject. In the \c Directory class, + the list of \c File objects is stored in a \c QList called \c m_fileList. + + \code + class File : public QObject{ + + Q_OBJECT + Q_PROPERTY(QString name READ name WRITE setName NOTIFY nameChanged) + + ... + }; + \endcode + + The properties can then be used in QML as part of the \c Directory element's + properties. Note that we do not have to create an identifier \c id property + in our C++ code. + + \code + Directory{ + id: directory + + filesCount + filename + fileContent + files + + files[0].name + } + + \endcode + + Because QML uses Javascript's syntax and structure, we can iterate through + the list of files and retrieve its properties. To retrieve the first file's + name property, we can call \c { files[0].name }. + + Regular C++ functions are also accessible from QML. The file loading and saving + functions are implemented in C++ and declared using the + \l {Q_INVOKABLE}{Q_INVOKABLE} macro. Alternatively, we can declare the functions + as a \c slot and the functions will be accessible from QML. + + \code + In Directory.h: + + Q_INVOKABLE void saveFile(); + Q_INVOKABLE void loadFile(); + \endcode + + The \c Directory class also has to notify other objects whenever the directory + contents change. This feature is performed using a \c signal. As previously + mentioned, QML signals have a corresponding handler with their names prepended + with \c on. The signal is called \c directoryChanged and it is emitted whenever + there is a directory refresh. The refresh simply reloads the directory contents + and updates the list of valid files in the directory. QML items can then be + notified by attaching an action to the \c onDirectoryChanged signal handler. + + The \c list properties need to be explored further. This is because list + properties use callbacks to access and modify the list contents. The list + property is of type \c QDeclarativeListProperty<File>. Whenever the list + is accessed, the accessor function needs to return a + \c QDeclarativeListProperty<File>. The template type, \c File, needs to be a + \c QObject derivative. Further, to create the + \l {QDeclarativeListProperty}{QDeclarativeListProperty}, the list's accessor + and modifiers need to be passed to the consructor as function pointers. The list, + a \c QList in our case, also needs to be a list of \c File pointers. + + The constructor of \l {QDeclarativeListProperty}{QDeclarativeListProperty} + constructor and the \c Directory implementation: + \code + QDeclarativeListProperty ( QObject * object, void * data, AppendFunction append, CountFunction count = 0, AtFunction at = 0, ClearFunction clear = 0 ) + QDeclarativeListProperty<File>( this, &m_fileList, &appendFiles, &filesSize, &fileAt, &clearFilesPtr ); + \endcode + + The constructor passes pointers to functions that will append the list, count + the list, retrieve the item using an index, and empty the list. Only the append + function is mandatory. Note that the function pointers must match the definition + of \l {QDeclarativeListProperty::AppendFunction}{AppendFunction}, + \l {QDeclarativeListProperty::CountFunction}{CountFunction}, + \l {QDeclarativeListProperty::AtFunction}{AtFunction}, or + \l {QDeclarativeListProperty::ClearFunction}{ClearFunction}. + + \code + void appendFiles(QDeclarativeListProperty<File> * property, File * file) + File* fileAt(QDeclarativeListProperty<File> * property, int index) + int filesSize(QDeclarativeListProperty<File> * property) + void clearFilesPtr(QDeclarativeListProperty<File> *property) + \endcode + + To simplify our file dialog, the \c Directory class filters out invalid text + files, which are files that do not have a \c .txt extension. If a file name + doesn't have the \c .txt extension, then it won't be seen in our file dialog. + Also, the implementation makes sure that saved files have a \c .txt extension in + the file name. \c Directory uses \l {QTextStream}{QTextStream} to read the file + and to output the file contents to a file. + + With our \c Directory element, we can retrieve the files as a list, know how many + text files is in the application directory, get the file's name and content as a + string, and be notified whenever there are changes in the directory contents. + + To build the plugin, run \c qmake on the \c cppPlugins.pro project file, then run + \c make to build and transfer the plugin to the \c plugins directory. + + + \section2 Importing a Plugin in QML + + The qmlviewer tool imports files that are in the same directory as the + application. We can also create a \c qmldir file containing the locations of + QML files we wish to import. The \c qmldir file can also store locations of + plugins and other resources. + + \code + In qmldir: + + Button ./Button.qml + FileDialog ./FileDialog.qml + TextArea ./TextArea.qml + TextEditor ./TextEditor.qml + EditMenu ./EditMenu.qml + + plugin FileDialog plugins + \endcode + + The plugin we just created is called \c FileDialog, as indicated by the + \c TARGET field in the project file. The compiled plugin is in the \c plugins directory. + + + \section2 Integrating a File Dialog into the File Menu + + Our \c FileMenu needs to display the \c FileDialog element, containing a list of + the text files in a directory thus allowing the user to select the file by + clicking on the list. We also need to assign the save, load, and new buttons + to their respective actions. The FileMenu contains an editable text input to + allow the user to type a file name using the keyboard. + + The \c Directory element is used in the \c FileMenu.qml file and it notifies the + \c FileDialog element that the directory refreshed its contents. This notification + is performed in the signal handler, \c onDirectoryChanged. + + \code + In FileMenu.qml: + + Directory{ + id:directory + filename: textInput.text + onDirectoryChanged: fileDialog.notifyRefresh() + } + \endcode + + Keeping with the simplicity of our application, the file dialog will always be + visible and will not display invalid text files, which do not have a \c .txt + extension to their filenames. + + \code + In FileDialog.qml: + + signal notifyRefresh() + onNotifyRefresh: dirView.model = directory.files + \endcode + + The \c FileDialog element will display the contents of a directory by reading its + list property called \c files. The files are used as the model of a + \l {GridView}{GridView} element, which displays data items in a grid according + to a delegate. The delegate handles the appearance of the model and our file + dialog will simply create a grid with text centered in the middle. Clicking on + the file name will result in the appearance of a rectangle to highlight the file + name. The \c FileDialog is notified whenever the \c notifyRefresh signal is emitted, + reloading the files in the directory. + + \code + In FileMenu.qml: + + Button{ + id: newButton + label: "New" + onButtonClick:{ + textArea.textContent = "" + } + } + Button{ + id: loadButton + label: "Load" + onButtonClick:{ + directory.filename = textInput.text + directory.loadFile() + textArea.textContent = directory.fileContent + } + } + Button{ + id: saveButton + label: "Save" + onButtonClick:{ + directory.fileContent = textArea.textContent + directory.filename = textInput.text + directory.saveFile() + } + } + Button{ + id: exitButton + label: "Exit" + onButtonClick:{ + Qt.quit() + } + } + \endcode + + Our \c FileMenu can now connect to their respective actions. The \c saveButton + will transfer the text from the \c TextEdit onto the directory's \c fileContent + property, then copy its file name from the editable text input. Finally, the button + calls the \c saveFile() function, saving the file. The \c sloadButton has a similar + execution. Also, the \c New action will empty the contents of the \c TextEdit. + + Further, the \c EditMenu buttons are connected to the \c TextEdit functions to copy, + paste, and select all the text in the text editor. + + \image qml-texteditor5_filemenu.png + + \section1 Text Editor Completion + + \image qml-texteditor5_newfile.png + + The application can function as a simple text editor, able to accept text + and save the text into a file. The text editor can also load from a file and + perform text manipulation. +*/ diff --git a/doc/src/getting-started/gettingstartedqt.qdoc b/doc/src/getting-started/gettingstartedqt.qdoc index 1b3770f..25d0ccd 100644 --- a/doc/src/getting-started/gettingstartedqt.qdoc +++ b/doc/src/getting-started/gettingstartedqt.qdoc @@ -28,8 +28,8 @@ /*! \page gettingstartedqt.html - \title Getting Started programming with Qt - \ingroup gettingStarted + \title Getting Started Programming with Qt + \ingroup gettingStarted Welcome to the world of Qt--the cross-platform GUI toolkit. In this getting started guide, we teach basic Qt knowledge by @@ -85,7 +85,7 @@ other widgets), it is possible to show a single widget in its own window. Widgets are not visible by default; the function \l{QWidget::}{show()} makes the widget visible. - + Line 11 makes the QApplication enter its event loop. When a Qt application is running, events are generated and sent to the widgets of the application. Examples of events are mouse presses diff --git a/doc/src/qt4-intro.qdoc b/doc/src/qt4-intro.qdoc index 8867fd9..3771bcc 100644 --- a/doc/src/qt4-intro.qdoc +++ b/doc/src/qt4-intro.qdoc @@ -455,10 +455,10 @@ \image quick_screens.png - Qt 4.7 introduces Quick, the Qt UI Creation Kit. that enables the creation - of dynamic user interfaces, easier and more effective than possible - with existing UI technologies. This UI Creation Kit consist of three - technologies: + Qt 4.7 introduces \l{Qt Quick}, the Qt UI Creation Kit. that enables + the creation of dynamic user interfaces, easier and more effective + than possible with existing UI technologies. This UI Creation Kit + consists of three technologies: \list \i QML is a declarative language oriented on JavaScript that utilizes |