qml与c++的简单实例，Connections信号连接

#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

#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();

}

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

}

}