drag-and-drop - QML:即使拖动属性处于事件状态，也未调用 onDragStarted/finished

Question

在下面的例子中，我希望 onDragStarted/onDragFinished当拖动一个矩形时调用。然而只有drag.onActiveChanged (鼠标区域的)和 Drag.onActiveChanged (矩形的称为)。设置 Drag.dragType 时我得到了预期的输出至 Drag.Automatic但后来我再也看不到矩形了。我在 Mac (El Capitan) 上使用 Qt 5.5。

import QtQuick 2.5
import QtQuick.Window 2.2

Window {
  visible: true

  width: 100
  height: 200

  ListModel {
    id: testModel
    ListElement { name: "red";   value: "#f00" }
    ListElement { name: "green"; value: "#0f0" }
    ListElement { name: "blue";  value: "#00f" }
  }

  Component {
    id: rect
    Rectangle {

      Drag.active: mouseArea.drag.active
      Drag.hotSpot.x: width / 2
      Drag.hotSpot.y: height / 2
      //Drag.dragType: Drag.Automatic

      Drag.onActiveChanged: {
        console.log("Active changed..")
      }

      Drag.onDragStarted: {
        console.log("Drag started..")
      }

      Drag.onDragFinished: {
        console.log("Drag finished!")
      }

      MouseArea {
        id: mouseArea

        anchors.fill: parent
        hoverEnabled: true
        drag.target: parent

        drag.onActiveChanged: {
          console.log("Drag prop became active..")
        }

        onClicked: {
          colorButtonClicked(buttonName, buttonColor);
        }
      }

      width: 80
      height: 20
      radius: 6
      color: model.value
    }
  }

  Column {
    spacing: 3
    anchors.centerIn: parent
    Repeater {
      model: testModel
      delegate: rect
    }
  }
}

Answer 1

基于我对信号名称的假设，我对同样的问题感到困惑，但看看 documentation表明信号仅在使用 Drag.Automatic 时有效或明确调用 startDrag .

dragStarted()

This signal is emitted when a drag is started with the startDrag() method or when it is started automatically using the dragType property.

dragFinished(DropAction action)

This signal is emitted when a drag finishes and the drag was started with the startDrag() method or started automatically using the dragType property.

使用 Drag.Automatic 时遇到的另一个问题似乎已在 Qt 5.6.1 中修复