diff options
Diffstat (limited to 'src/declarative/qml/qdeclarativeengine.cpp')
-rw-r--r-- | src/declarative/qml/qdeclarativeengine.cpp | 66 |
1 files changed, 53 insertions, 13 deletions
diff --git a/src/declarative/qml/qdeclarativeengine.cpp b/src/declarative/qml/qdeclarativeengine.cpp index f2eb770..e3ebca3 100644 --- a/src/declarative/qml/qdeclarativeengine.cpp +++ b/src/declarative/qml/qdeclarativeengine.cpp @@ -115,22 +115,55 @@ QT_BEGIN_NAMESPACE /*! \qmlclass QtObject QObject \since 4.7 - \brief The QtObject element is the most basic element in QML + \brief The QtObject element is the most basic element in QML. The QtObject element is a non-visual element which contains only the - objectName property. It is useful for when you need an extremely - lightweight element to place your own custom properties in. + objectName property. + + It can be useful to create a QtObject if you need an extremely + lightweight element to enclose a set of custom properties: + + \snippet doc/src/snippets/declarative/qtobject.qml 0 It can also be useful for C++ integration, as it is just a plain QObject. See the QObject documentation for further details. */ /*! \qmlproperty string QML:QtObject::objectName - This property allows you to give a name to this specific object instance. + This property holds the QObject::objectName for this specific object instance. + + This allows a C++ application to locate an item within a QML component + using the QObject::findChild() method. For example, the following C++ + application locates the child \l Rectangle item and dynamically changes its + \c color value: + + \qml + // MyRect.qml + + import Qt 4.7 + + Item { + width: 200; height: 200 + + Rectangle { + anchors.fill: parent + color: "red" + objectName: "myRect" + } + } + \endqml + + \code + // main.cpp - See \l{scripting.html#accessing-child-qobjects}{Accessing Child QObjects} - in the scripting documentation for details how objectName can be used from - scripts. + QDeclarativeView view; + view.setSource(QUrl::fromLocalFile("MyRect.qml")); + view.show(); + + QDeclarativeItem *item = view.rootObject()->findChild<QDeclarativeItem*>("myRect"); + if (item) + item->setProperty("color", QColor(Qt::yellow)); + \endcode */ struct StaticQtMetaObject : public QObject @@ -545,9 +578,9 @@ void QDeclarativeEngine::clearComponentCache() component instances should be added to sub-contexts parented to the root context. */ -QDeclarativeContext *QDeclarativeEngine::rootContext() +QDeclarativeContext *QDeclarativeEngine::rootContext() const { - Q_D(QDeclarativeEngine); + Q_D(const QDeclarativeEngine); return d->rootContext; } @@ -1080,13 +1113,20 @@ Here is an example. Notice it checks whether the component \l{Component::status} \c Component.Ready before calling \l {Component::createObject()}{createObject()} in case the QML file is loaded over a network and thus is not ready immediately. -\snippet doc/src/snippets/declarative/componentCreation.js 0 +\snippet doc/src/snippets/declarative/componentCreation.js vars +\codeline +\snippet doc/src/snippets/declarative/componentCreation.js func +\snippet doc/src/snippets/declarative/componentCreation.js remote +\snippet doc/src/snippets/declarative/componentCreation.js func-end \codeline -\snippet doc/src/snippets/declarative/componentCreation.js 1 +\snippet doc/src/snippets/declarative/componentCreation.js finishCreation -If you are certain the files will be local, you could simplify to: +If you are certain the QML file to be loaded is a local file, you could omit the \c finishCreation() +function and call \l {Component::createObject()}{createObject()} immediately: -\snippet doc/src/snippets/declarative/componentCreation.js 2 +\snippet doc/src/snippets/declarative/componentCreation.js func +\snippet doc/src/snippets/declarative/componentCreation.js local +\snippet doc/src/snippets/declarative/componentCreation.js func-end To create a QML object from an arbitrary string of QML (instead of a file), use \l{QML:Qt::createQmlObject()}{Qt.createQmlObject()}. |