QML:如何拒绝放置操作 [英] QML: How to reject drop action
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问题描述
我有一个 DropArea
和两个元素.如果 DropArea
已经让一个元素被删除,我希望 DropArea
拒绝放置事件,另一个元素不允许放入,除非第一个元素移出.
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
}
但看起来 drop.accepted
不起作用,顺便说一句,无论如何要在 DropArea
But looks like drop.accepted
not work,
BTW anyway to get the objects was dropped in DropArea
推荐答案
您应该控制是否必须在 onReleased
中删除该项目,检查 dropped
属性.
You should control if the item must be dropped or not in onReleased
, checking the dropped
property.
完整示例:
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;
}
}
}
}
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