Bug? Draggable Items in GridView: MouseArea stops working after Drop



  • Hi,

    I have a GridView with draggable items, basically Qt's draganddrop example. I pasted the code below. As you see, I have a MouseArea: myProblematicMouseArea, and I want it to perform an Action onPressAndHold, but only if the item is not being dragged. This works at the beginning, but as soon as an item is dropped, the mouseArea is not working correctly, and misses my clicks. Then after some clicks it starts working again. Am I missing something?

    Does it have something to do with the reparenting of icon?

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    import QtQuick 2.12
    import QtQml.Models 2.1
    
    GridView {
        id: root
        width: 320; height: 480
        cellWidth: 80; cellHeight: 80
    
        displaced: Transition {
            NumberAnimation { properties: "x,y"; easing.type: Easing.OutQuad }
        }
    
    //! [0]
        model: DelegateModel {
    //! [0]
            id: visualModel
            model: ListModel {
                id: colorModel
                ListElement { color: "blue" }
                ListElement { color: "green" }
                ListElement { color: "red" }
                ListElement { color: "yellow" }
                ListElement { color: "orange" }
                ListElement { color: "purple" }
                ListElement { color: "cyan" }
                ListElement { color: "magenta" }
                ListElement { color: "chartreuse" }
                ListElement { color: "aquamarine" }
                ListElement { color: "indigo" }
                ListElement { color: "black" }
                ListElement { color: "lightsteelblue" }
                ListElement { color: "violet" }
                ListElement { color: "grey" }
                ListElement { color: "springgreen" }
                ListElement { color: "salmon" }
                ListElement { color: "blanchedalmond" }
                ListElement { color: "forestgreen" }
                ListElement { color: "pink" }
                ListElement { color: "navy" }
                ListElement { color: "goldenrod" }
                ListElement { color: "crimson" }
                ListElement { color: "teal" }
            }
    //! [1]
            delegate: DropArea {
                id: delegateRoot
    
                width: 80; height: 80
    
                onEntered: visualModel.items.move(drag.source.visualIndex, icon.visualIndex)
                property int visualIndex: DelegateModel.itemsIndex
                Binding { target: icon; property: "visualIndex"; value: visualIndex }
    
                Rectangle {
                    id: icon
                    property int visualIndex: 0
                    width: 72; height: 72
                    anchors {
                        horizontalCenter: parent.horizontalCenter;
                        verticalCenter: parent.verticalCenter
                    }
                    radius: 3
                    color: model.color
                    MouseArea {
                        id: myProblematicMouseArea
                        anchors.fill: parent
                        onPressAndHold: {
                            // only trigger if drag is not active)
                            console.log("is drag active? ",icon.Drag.active)
                            if(icon.Drag.active==false)
                                console.log("press and hold triggered")
                        }
                    onClicked: {
                        console.log("clicked")
                    }
                    }
    
                    Text {
                        anchors.centerIn: parent
                        color: "white"
                        text: parent.visualIndex
                    }
    
                    DragHandler {
                        id: dragHandler
                    }
    
                    Drag.active: dragHandler.active
                    Drag.source: icon
                    //Drag.dragType: Drag.Automatic
                    Drag.hotSpot.x: 36
                    Drag.hotSpot.y: 36
                    Drag.onDragStarted: {
                        console.log("drag started")
                    }
    
                    states: [
                        State {
                            when: icon.Drag.active
                            ParentChange {
                                target: icon
                                parent: root
                            }
    
                            AnchorChanges {
                                target: icon
                                anchors.horizontalCenter: undefined
                                anchors.verticalCenter: undefined
                            }
                        }
                    ]
                }
            }
    //! [1]
        }
    }


  • It would already be helpful, if someone can reproduce this behaviour. The MouseArea writes a message via console.log if a click was received. The problem is, that after a drag, the MouseArea onClicked Event is not triggered anymore, only after some clicks it starts responding again.



  • Here's what I noticed: every square that was dragged stops reacting to single clicks, but if you do double-click on it, then it will react to it, and then will continue reacting to single clicks as well. And other squares react to clicks just fine (till you drag them).

    If that's what you wanted to reproduce, then it is reproduced by me.

    Doesn't look like designed behavior to me, I guess we need to report it. But for what component, is it DropArea who causes the trouble?



  • Thank you very much. I reported it here
    https://bugreports.qt.io/browse/QTBUG-73735


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