javascript - 在 QML 中通过鼠标点击推送项目时，不会调用数组的 onChanged 属性

Question

Access.qml

import QtQuick 2.0

Rectangle {
    id: newq

    width: 100
    height: 62

    property var pp : [1]

    onPpChanged:
    {
        console.log("\non pp changed, show pp's length: " +  pp.length)
    }

    property int inde : 0

    MouseArea
    {
        anchors.fill: parent
        onClicked:
        {
            pp.push (inde++)
            console.log("mousearea shows pp's length: " + pp.length)
        }
    }
}

main.qml

import QtQuick 2.0

Rectangle {
    id: root
    width: 360
    height: 360

    Access
    {
        color: "red"
    }
}

输出(鼠标点击):

QML debugging is enabled. Only use this in a safe environment.

on pp changed, show pp's length: 1
mousearea shows pp's length: 2
mousearea shows pp's length: 3
mousearea shows pp's length: 4
mousearea shows pp's length: 5

当我在 pp 中推送项目时，为什么没有调用 onPpChanged？我该怎么做才能调用它？

Answer 1

这是因为 QML 中的数组不是 QML 对象。 documentation说:

Additionally, since [...] are not QML objects, changing their individual values do not trigger property change notifications. If the above example had onNumberChanged or onAnimalChanged signal handlers, they would not have been called. If, however, the items or attributes properties themselves were reassigned to different values, then such handlers would be called.

因此，为了让您的代码正常工作，您需要在修改数组时自己抛出信号。所以你的代码应该是这样的:

  MouseArea
  {
      anchors.fill: parent
      onClicked:
      {
          pp.push(inde++);
          ppChanged();
          console.log("mousearea shows pp's length: " + pp.length);
      }
  }