diff options
Diffstat (limited to 'src/declarative/graphicsitems/qdeclarativemousearea.cpp')
| -rw-r--r-- | src/declarative/graphicsitems/qdeclarativemousearea.cpp | 83 |
1 files changed, 61 insertions, 22 deletions
diff --git a/src/declarative/graphicsitems/qdeclarativemousearea.cpp b/src/declarative/graphicsitems/qdeclarativemousearea.cpp index 4685e65..a0208ef 100644 --- a/src/declarative/graphicsitems/qdeclarativemousearea.cpp +++ b/src/declarative/graphicsitems/qdeclarativemousearea.cpp @@ -185,27 +185,57 @@ QDeclarativeMouseAreaPrivate::~QDeclarativeMouseAreaPrivate() \brief The MouseArea item enables simple mouse handling. \inherits Item - A MouseArea is typically used in conjunction with a visible item, - where the MouseArea effectively 'proxies' mouse handling for that - item. For example, we can put a MouseArea in a \l Rectangle that changes + A MouseArea is an invisible item that is typically used in conjunction with + a visible item in order to provide mouse handling for that item. + By effectively acting as a proxy, the logic for mouse handling can be + contained within a MouseArea item. + + For basic key handling, see the \l{Keys}{Keys attached property}. + + The \l enabled property is used to enable and disable mouse handling for + the proxied item. When disabled, the mouse area becomes transparent to + mouse events. + + The \l pressed read-only property indicates whether or not the user is + holding down a mouse button over the mouse area. This property is often + used in bindings between properties in a user interface. The containsMouse + read-only property indicates the presence of the mouse cursor over the + mouse area but, by default, only when a mouse button is held down; see below + for further details. + + Information about the mouse position and button clicks are provided via + signals for which event handler properties are defined. The most commonly + used involved handling mouse presses and clicks: onClicked, onDoubleClicked, + onPressed, onReleased and onPressAndHold. + + By default, MouseArea items only report mouse clicks and not changes to the + position of the mouse cursor. Setting the hoverEnabled property ensures that + handlers defined for onPositionChanged, onEntered and onExited are used and + that the containsMouse property is updated even when no mouse buttons are + pressed. + + \section1 Example Usage + + \beginfloatright + \inlineimage qml-mousearea-snippet.png + \endfloat + + The following example uses a MouseArea in a \l Rectangle that changes the \l Rectangle color to red when clicked: - \snippet doc/src/snippets/declarative/mousearea.qml import + \snippet doc/src/snippets/declarative/mousearea/mousearea.qml import \codeline - \snippet doc/src/snippets/declarative/mousearea.qml intro + \snippet doc/src/snippets/declarative/mousearea/mousearea.qml intro - Many MouseArea signals pass a \l {MouseEvent}{mouse} parameter that contains + \clearfloat + Many MouseArea signals pass a \l{MouseEvent}{mouse} parameter that contains additional information about the mouse event, such as the position, button, and any key modifiers. Here is an extension of the previous example that produces a different color when the area is right clicked: - \snippet doc/src/snippets/declarative/mousearea.qml intro-extended - - For basic key handling, see the \l {Keys}{Keys attached property}. - - MouseArea is an invisible item: it is never painted. + \snippet doc/src/snippets/declarative/mousearea/mousearea.qml intro-extended \sa MouseEvent, {declarative/touchinteraction/mousearea}{MouseArea example} */ @@ -312,11 +342,14 @@ QDeclarativeMouseAreaPrivate::~QDeclarativeMouseAreaPrivate() \qmlsignal MouseArea::onCanceled() This handler is called when mouse events have been canceled, either because an event was not accepted, or - because another element stole the mouse event handling. This signal is for advanced use: it is useful when - there is more than one MouseArea that is handling input, or when there is a MouseArea inside a \l Flickable. In the latter - case, if you execute some logic on the pressed signal and then start dragging, the \l Flickable will steal the mouse handling - from the MouseArea. In these cases, to reset the logic when the MouseArea has lost the mouse handling to the - \l Flickable, \c onCanceled should be used in addition to onReleased. + because another element stole the mouse event handling. + + This signal is for advanced use: it is useful when there is more than one MouseArea + that is handling input, or when there is a MouseArea inside a \l Flickable. In the latter + case, if you execute some logic on the pressed signal and then start dragging, the + \l Flickable will steal the mouse handling from the MouseArea. In these cases, to reset + the logic when the MouseArea has lost the mouse handling to the \l Flickable, + \c onCanceled should be used in addition to onReleased. */ QDeclarativeMouseArea::QDeclarativeMouseArea(QDeclarativeItem *parent) @@ -333,11 +366,13 @@ QDeclarativeMouseArea::~QDeclarativeMouseArea() /*! \qmlproperty real MouseArea::mouseX \qmlproperty real MouseArea::mouseY - These properties hold the coordinates of the mouse. + These properties hold the coordinates of the mouse cursor. If the hoverEnabled property is false then these properties will only be valid while a button is pressed, and will remain valid as long as the button is held - even if the mouse is moved outside the area. + down even if the mouse is moved outside the area. + + By default, this property is false. If hoverEnabled is true then these properties will be valid when: \list @@ -362,6 +397,8 @@ qreal QDeclarativeMouseArea::mouseY() const /*! \qmlproperty bool MouseArea::enabled This property holds whether the item accepts mouse events. + + By default, this property is true. */ bool QDeclarativeMouseArea::isEnabled() const { @@ -389,7 +426,8 @@ void QDeclarativeMouseArea::setEnabled(bool a) \endlist The code below displays "right" when the right mouse buttons is pressed: - \snippet doc/src/snippets/declarative/mousearea.qml mousebuttons + + \snippet doc/src/snippets/declarative/mousearea/mousearea.qml mousebuttons \sa acceptedButtons */ @@ -707,7 +745,8 @@ QVariant QDeclarativeMouseArea::itemChange(GraphicsItemChange change, pressed. Hover enables handling of all mouse events even when no mouse button is pressed. - This property affects the containsMouse property and the onEntered, onExited and onPositionChanged signals. + This property affects the containsMouse property and the onEntered, onExited and + onPositionChanged signals. */ bool QDeclarativeMouseArea::hoverEnabled() const { @@ -850,7 +889,7 @@ QDeclarativeDrag *QDeclarativeMouseArea::drag() The following example displays a \l Rectangle that can be dragged along the X-axis. The opacity of the rectangle is reduced when it is dragged to the right. - \snippet doc/src/snippets/declarative/mousearea.qml drag + \snippet doc/src/snippets/declarative/mousearea/mousearea.qml drag \note Items cannot be dragged if they are anchored for the requested \c drag.axis. For example, if \c anchors.left or \c anchors.right was set @@ -861,7 +900,7 @@ QDeclarativeDrag *QDeclarativeMouseArea::drag() If \c drag.filterChildren is set to true, a drag can override descendant MouseAreas. This enables a parent MouseArea to handle drags, for example, while descendants handle clicks: - \snippet doc/src/snippets/declarative/mouseareadragfilter.qml dragfilter + \snippet doc/src/snippets/declarative/mousearea/mouseareadragfilter.qml dragfilter */ |