Detect press and hold of a Button in QML

问题

I'd like to open a context menu when a user presses and holds a Button (I use Button for convenience). If I do

    Button
    {
        text: model.ualabel

        MouseArea
        {
            preventStealing: true
            anchors.fill: parent
            onPressAndHold: uaContextMenu.open()
        }

        ContextMenu
        {
            id: uaContextMenu
            MenuLayout
            {
                MenuItem { /**/ } 
            }
        }
    }

then the MouseArea responsible for pressAndHold steals all gestures even though and the Button cannot be clicked. What am I doing wrong? I'm using Qt 4.7 and importing QtQuick 1.1 and com.nokia.meego 1.0

Thanks

回答1:

I've found that press-and-hold can be simulated on QML's Button like this:

Button {
    id: button

    signal pressAndHold()

    Timer {
        id: longPressTimer

        interval: 2000 //your press-and-hold interval here
        repeat: false
        running: false

        onTriggered: {
            button.pressAndHold()
        }
    }


    onPressedChanged: {
        if ( pressed ) {
            longPressTimer.running = true;
        } else {
            longPressTimer.running = false;
        }
    }
}

回答2:

The problem is your mouse area is competing with the Button's mouse area to receive mouse events. Try setting propogateComposedEvents: true on your mouse area and this should allow event to propogate downwards in the visual stack to the button's mouse area. Refer to http://qt-project.org/doc/qt-5.0/qtquick/qml-qtquick2-mousearea.html#propagateComposedEvents-prop for more details.

After reading the comments, my new suggestion is to manually propagate the clicked signal in your mouseArea to the button. This should be doable by calling buttonId.clicked() which will manually emit the clicked signal on your button.

来源：https://stackoverflow.com/questions/17857570/detect-press-and-hold-of-a-button-in-qml

标签

button

qt4

qml