QML: How to reject drop action - qt

Question

I have one DropArea and two elements. I want DropArea reject the drop event if the DropArea already got one element be dropped, the another element not allow drop into, unless the first one move out.
DropArea {
property bool dropped: false
onDropped: {
drop.accepted = !dropped;
dropped = true;
}
onExited: dropped = false
}
But looks like drop.accepted not work,
BTW anyway to get the objects was dropped in DropArea

Answer 1

You should control if the item must be dropped or not in onReleased, checking the dropped property.
Full example:
import QtQuick 2.5
import QtQuick.Window 2.2
import QtQuick.Controls 1.4
Window {
id: win
visible: true
width: 800
height: 600
title: qsTr("Hello World")
Repeater {
model: 10
Rectangle {
id: rect
width: 50
height: 50
z: mouseArea.drag.active || mouseArea.pressed ? 2 : 1
color: Qt.rgba(Math.random(), Math.random(), Math.random(), 1)
x: Math.random() * (win.width / 2 - 100)
y: Math.random() * (win.height - 100)
property point beginDrag
property bool caught: false
border { width:2; color: "white" }
radius: 5
Drag.active: mouseArea.drag.active
Text {
anchors.centerIn: parent
text: index
color: "white"
}
MouseArea {
id: mouseArea
anchors.fill: parent
drag.target: parent
onPressed: {
rect.beginDrag = Qt.point(rect.x, rect.y);
}
onReleased: {
if(!rect.caught || dragTarget.dropped) {
backAnimX.from = rect.x;
backAnimX.to = beginDrag.x;
backAnimY.from = rect.y;
backAnimY.to = beginDrag.y;
backAnim.start()
}
parent.Drag.drop()
console.log("MouseArea - containsDrag " + dragTarget.dropped)
}
}
ParallelAnimation {
id: backAnim
SpringAnimation { id: backAnimX; target: rect; property: "x";
duration: 500; spring: 2; damping: 0.2 }
SpringAnimation { id: backAnimY; target: rect; property: "y";
duration: 500; spring: 2; damping: 0.2 }
}
}
}
Rectangle {
anchors {
top: parent.top
right: parent.right
bottom: parent.bottom
}
width: parent.width / 2
color: "gold"
DropArea {
id: dragTarget
anchors.fill: parent
property bool dropped: false
onEntered: {
console.log("onEntered " + containsDrag)
drag.source.caught = true;
}
onExited: {
console.log("onExited " + containsDrag)
dropped = false;
}
onDropped:
{
console.log("onDropped");
dropped = true;
}
}
}
}

Answer 2

Use drop.accept() instead. The above can be done as follows:
property bool containsItem: false
DropArea {
id: dropArea
anchors.fill: parent
onDropped: {
if(containsItem)
drop.accept(Qt.IgnoreAction)
else
drop.accept()
containsItem = true;
}
}
Also donot use dropped property as it is already an attached property inside onDropped event handler.
Edit:
If rect is the Item to be dragged and dropped then:
Rectangle {
id: rect
width: 40; height: 40
color: "red"
Drag.active: dragArea.drag.active
Drag.hotSpot.x: 20
Drag.hotSpot.y: 20
MouseArea {
id: dragArea
anchors.fill: parent
drag.target: parent
onReleased: if (rect.Drag.drop() !== Qt.IgnoreAction) {
console.log("Accepted!");
} else {
console.log("Rejected!");
}
}
}