Drag and Drop in separate windows

shkryab

I'm trying to do drag and drop between different windows. Code drag the same as in еxample externaldraganddrop. Problem: If after dragging one element from window to window to try to drag the other is dragged back first element. If before the next mouse click drag to make it dragged the item. What could I miss that?

SGaist

Hi,

It's not really clear. Could you show an example of what is happening ?

shkryab

Sorry for my english. :)

Code and video with bug:

@
import QtQuick 2.2
import QtQuick.Window 2.0

Window {

ListView {
    id: list
    anchors.fill: parent

    model: 5

    delegate: Rectangle {
        width: list.width
        height: 30
        border.color: "black"
        border.width: 1

        Text {
            anchors.fill: parent
            text: index
        }

        Item {
            id: draggable
            anchors.fill: parent
            Drag.active: mouseArea.drag.active
            Drag.hotSpot.x: 0
            Drag.hotSpot.y: 0
            Drag.mimeData: { "mediaItem": index }
            Drag.dragType: Drag.Automatic
            Drag.onDragStarted: {
            }
            Drag.onDragFinished: {
            }
        }

        MouseArea {
            id: mouseArea
            anchors.fill: parent

            drag.target: draggable
        }
    }
}

Window {
    visible: true

    Text {
        id:text
        anchors.fill: parent
    }

    DropArea {
        anchors.fill: parent

        keys: ["mediaItem"]

        onDropped: {
            text.text += drop.source.mimeData["mediaItem"]
            drop.acceptProposedAction()
        }
    }
}

}
@

"Video":http://youtu.be/8XFeAA_ry14

SGaist

Do you have the same effect if you use the same code as the documentation ?

shkryab

The code above is the same as in the "example from the documentation":http://qt-project.org/doc/qt-5/qtquick-externaldraganddrop-example.html but with a few changes.

SGaist

That's why I asked you to run it unmodified so as to see whether you have the same strange behavior.

shkryab

Yes exactly. Such a behavior between two separate windows of the same application only. I tried to run unchanged code sample in two windows as a two different applications and as an one.

SGaist

I'm not sure I'm understanding you correctly. Are you saying that with the code from the example, you get the same behavior you are currently getting with your original software ?

shkryab

Yes. It's the same behavior all the time with two separate windows of the same application.

SGaist

Sounds like this could be a bug. Have a look at the "bug report system":http://bugreports.qt-project.org to see if it's something known. If not please consider opening a new report providing a minimal compilable example that reproduce the behavior

djdevs

I'm not able to see the video link, probably because the post is quite long ago.
The issue that I see from the code above is the data is not able to be transferred from the drag area to the drop area between different windows.

To resolve the issue, I had save the value in the property of the drag area, and retrieved this value from the drop area.
Here's the full code. Code changes are commented as //Changes here

import QtQuick 2.2
import QtQuick.Window 2.0

Window {
    width: 800
    height: 600
    visible: true

    ListView {
        id: list
        anchors.fill: parent

        model: 5

        delegate: Rectangle {
            width: list.width
            height: 30
            border.color: "black"
            border.width: 1

            Text {
                anchors.fill: parent
                text: index
            }

            Item {
                id: draggable
                anchors.fill: parent
                property var saved_value //Changes here

                Drag.active: mouseArea.drag.active
                Drag.hotSpot.x: 0
                Drag.hotSpot.y: 0
                Drag.mimeData: {
                    "mediaItem": index
                }
                Drag.dragType: Drag.Automatic
                Drag.onDragStarted: {
                    saved_value = index //Changes here
                }
                Drag.onDragFinished: {

                }
            }

            MouseArea {
                id: mouseArea
                anchors.fill: parent

                drag.target: draggable
            }
        }
    }

    Window {
        visible: true

        Text {
            id: text
            anchors.fill: parent
        }

        DropArea {
            anchors.fill: parent

            keys: ["mediaItem"]

            onDropped: drop => {
                           text.text += drop.source.saved_value //Changes here
                           drop.acceptProposedAction()
                       }
        }
    }
}