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

maxwell31

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]
    }
}

maxwell31

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.

veryqtperson

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?

maxwell31

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