1、QML呼叫C++函式

      C++中定義：

    Q_INVOKABLE void clearChart();

<pre name="code" class="cpp">void PieChart::clearChart()
{
    setColor(QColor(Qt::transparent));
    update();

   // emit chartCleared();
}

    MouseArea {
        anchors.fill: parent
        onClicked: aPieChart.clearChart()
    }
 

signals:
    void chartCleared();

void PieChart::clearChart()
{
   emit chartCleared();
}

QML接收執行

    PieChart {
        id: aPieChart
        anchors.centerIn: parent
        width: 100; height: 100
        color: "red"

        onChartCleared: console.log("The chart has been cleared")
    }