【转】QML调用C++

myclass.h

1. #ifndef MYCLASS_H
2. #define MYCLASS_H
4. #include <QObject>
5. #include<QString>
6. class MyClass : public QObject
7. {
8. Q_OBJECT
9. //暴露给QML 属性
10. Q_PROPERTY(QString mystring READ getString WRITE setString NOTIFY mystringChanged)
11. private:
12. QString * m_pstring;
13. public:
14. explicit MyClass(QObject *parent = 0);
15. Q_INVOKABLE QString getString(); //Q_INVOCABLE暴露给 QML
16. Q_INVOKABLE void setString(QString string);
17. ~MyClass();
19. signals:
20. void mystringChanged(QString value); //信号
21. public slots:
23. };
25. #endif // MYCLASS_H

myclass.cpp

1. #include "myclass.h"
3. MyClass::MyClass(QObject *parent) : QObject(parent)
4. {
5. this->m_pstring=new QString("默认值");
6. }
8. MyClass::~MyClass()
9. {
10. delete this->m_pstring;
11. }
12. QString MyClass::getString()
13. {
14. setString("xx");
15. return *(this->m_pstring);
16. }
17. void MyClass::setString(QString string){
18. *(this->m_pstring)=string;
19. emit mystringChanged(string);//发送信号
20. }

main.cpp

1. #include <QGuiApplication>
2. #include <QQmlApplicationEngine>
3. #include<QtQml>
4. #include<myclass.h>
5. int main(int argc, char *argv[])
6. {
7. QGuiApplication app(argc, argv);
8. //注册到QML，留意注册函数所在的位置
9. qmlRegisterType<MyClass>("RegisterMyType",1,0,"MyClassType");
10. QQmlApplicationEngine engine;
11. engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
13. return app.exec();
14. }

main.qml

1. import QtQuick 2.4
2. import QtQuick.Window 2.2
3. import QtQuick.Controls 1.2
4. import QtQuick.Controls.Styles 1.2
5. import RegisterMyType 1.0 //导入
6. Window {
7. visible: true
8. Button{
9. id:btn1;
10. height:20;
11. width:60;
12. text:"按钮";
13. onClicked: {
14. //qml操作c++
15. btn1.text=myobj.mystring;
16. }
17. }
18. Label{
19. id:label1;
20. text:"初始值";
21. anchors.left:btn1.right;
22. anchors.leftMargin: 12;
23. }
24. //创建对象
25. MyClassType
26. {
27. id:myobj;
28. }
29. //连接信号 到qml
30. Connections{
31. target:myobj;
32. onMystringChanged:label1.text="改变了值是："+value; //这里的value是signal信号函数里面的参数
33. }
35. }