Dragging Issue: Draggable keeps shifting position after dragging from one location to another

fcarney

This code illustrates the problem:

import QtQuick 2.12
import QtQuick.Window 2.12

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Dragon Drop: drag to window")

    ColorAnimation on color {
        id: rejectAnimation

        running: false
        from: "#FCC"
        to: "#EEE"
        duration: 1000
    }

    DropArea {
        id: dropArea
        anchors.fill: parent
        keys: ["amet/pathkey"]
        onEntered: (drag) => {
            if(drag.proposedAction != Qt.CopyAction){
                drag.accepted = false
                rejectAnimation.start()
            }
        }
        onDropped: (drop) => {
            var textdata = drop.getDataAsString(keys[0])
            if (textdata.length) {
                if (drop.proposedAction == Qt.CopyAction) {
                    console.log(textdata)
                    drop.acceptProposedAction()
                }
            }
        }
    }

    Window {
        id: side_window

        title: "drag from window"
        visible: true

        width: 400
        height: 400

        MouseArea {
            id: mouseArea
            anchors.fill: parent
            drag.target: draggable
            onPressed: draggable.grabToImage(function(result) {
                draggable.Drag.imageSource = result.url
            })
        }
        Rectangle {
            id: item

            property string display: "data"

            Rectangle {
                id: draggable

                width: 32
                height: 32

                Drag.active: mouseArea.drag.active
                Drag.hotSpot.x: 0
                Drag.hotSpot.y: 0
                Drag.mimeData: { "amet/pathkey": "text data" }
                Drag.dragType: Drag.Automatic
                Drag.supportedActions: Qt.CopyAction
                Drag.onDragFinished: (dropAction) => {
                    //if (dropAction == Qt.MoveAction)
                    //    item.display = ""
                    draggable.x = 0
                    draggable.y = 0
                }

                color: "white"
                border.width: 1
            }
        }
    }
}

The draggable (square box in the drag from window) keeps shifting position after a drag. I don't want it to move. I cannot find the magic setting to keep this from happening. If this drag would not shift it would be perfectly fine.

I previously was using Qt.Internal for dragType, but it has more problems dragging between windows. Dragging within one window it is okay.

Frustrated as both drag types seem to have strange issues. This shifting of the draggable is strange.

fcarney

Wow, why do I find it when I send a message? Anyway, I found a somewhat hacky fix:

             Rectangle {
                id: draggable

                width: 32
                height: 32

                Drag.active: mouseArea.drag.active
                Drag.hotSpot.x: 0
                Drag.hotSpot.y: 0
                Drag.mimeData: { "amet/pathkey": "text data" }
                Drag.dragType: Drag.Automatic
                Drag.supportedActions: Qt.CopyAction
                Drag.onDragFinished: (dropAction) => {
                    Qt.callLater(fixpos, x,y)
                }

                function fixpos(x, y){
                    draggable.x = x
                    draggable.y =y
                }

                color: "white"
                border.width: 1
            }

Use callLater to set the x and y to the original x and y of the predrag operation. This seems to postfix the problem fine.