qml与c++的简单实例，Connections信号连接

头文件如下：

#ifndef WIDGET_H

#define WIDGET_H

#include <QWidget>

#include <QQuickWidget>

#include <QQmlContext>

class Widget : public QWidget

{

    Q_OBJECT

    Q_PROPERTY(int _width READ returnW NOTIFY rectChanged)

    Q_PROPERTY(int _height READ returnH NOTIFY rectChanged)

public:

    Widget(QWidget *parent = 0);

    ~Widget();

    int returnW(){return _width = width();}

    int returnH(){return _height = height();}

    void resizeEvent(QResizeEvent *event);

signals:

    void rectChanged();

private:

    int _width, _height;

    QQuickWidget *qmlWidget;

};

#endif // WIDGET_H

Widget类源文件

#include "widget.h"

Widget::Widget(QWidget *parent)

    : QWidget(parent)

{

    qmlWidget = new QQuickWidget(this);

    qmlWidget->rootContext()->setContextProperty("View",this);

    qmlWidget->setSource(QUrl(QStringLiteral("qrc:/Connections.qml")));

    resize(640,450);

}

Widget::~Widget()

{

    if(qmlWidget != NULL)

    {

        delete qmlWidget;

        qmlWidget = NULL;

    }

}

void Widget::resizeEvent(QResizeEvent *event)

{

    emit rectChanged();

}

qml文件，记得要把qml文件放到资源文件里面去哦

import QtQuick 2.0

import QtQuick.Controls 1.4

Rectangle {

    width: View._width

    height: View._height

    color: "green"

    Text {

        id: text1

        text: qsTr("text one")

        anchors.horizontalCenter: parent.horizontalCenter

        anchors.top: parent.top

        anchors.topMargin: 30

        color: "blue"

        font.pixelSize: 18

    }

    Text {

        id: text2

        text: qsTr("text two")

        anchors.horizontalCenter: parent.horizontalCenter

        anchors.top: text1.bottom

        anchors.topMargin: 50;

        color: "yellow"

        font.pixelSize: 18

    }

    Button {

        id: btn

        anchors.horizontalCenter: parent.horizontalCenter

        anchors.top: text2.bottom

        anchors.topMargin: 50

        text: "Change"

    }

    Connections {

        target: btn

        onClicked: {

            text1.color = Qt.rgba(Math.random(),Math.random(),Math.random(),1);

            text2.color = Qt.rgba(Math.random(),Math.random(),Math.random(),1);

        }

//        //类似的如果想用Widget里面的信号如下：
//        target: View
//        onRectChanged: test

    }

}