Qt之qml和widget混合编程调用

首先是创建一个widget项目

然后需要添加qml和quick的插件使用
QT += quickwidgets qml
接着要在界面上创建一个quickwidget和按钮

创建一个c++对象类
QObjectQml

#ifndef QOBJECTQML_H
#define QOBJECTQML_H

#include 
#include 
class QObjectQml : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString deviceId READ getDeviceId WRITE setDeviceId)
    //这里进行属性绑定
public:
    explicit QObjectQml(QObject *parent = nullptr);

    //内部函数
    QString getDeviceId() {return deviceId;}
    void setDeviceId(QString id);
signals:

public slots:
     void funDemo(QString str);

private:
    QString deviceId;
};

#endif // QOBJECTQML_H

cpp实现文件

#pragma execution_character_set("utf-8")
#include "qobjectqml.h"

QObjectQml::QObjectQml(QObject *parent) : QObject(parent)
{

}

void QObjectQml::setDeviceId(QString id)
{
    deviceId = id;
    qDebug()<<"setDeviceId 数据库发生改变";
}

void QObjectQml::funDemo(QString str)
{
     qDebug()<<"我是c++函数被调用funDemo"<<str;
}

注册c++对象到系统中

#pragma execution_character_set("utf-8")
#include "mainwidget.h"
#include 
#include "qobjectqml.h"
#include 
#include 
#include 

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    //将c++类以类型的方式注册到qml中
    qmlRegisterType<QObjectQml>("QObjectQml.module",1,0,"QObjectQml");

    MainWidget w;
    w.show();

    return a.exec();
}

接着c++的界面对象中调用即可

#include "mainwidget.h"
#include "ui_mainwidget.h"
#include 

#include "qobjectqml.h"
#include 
#include 
#include 

MainWidget::MainWidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::MainWidget)
{
    ui->setupUi(this);

    //界面上的quickWidget添加qml
    ui->quickWidget->setSource(QUrl::fromLocalFile(":/mainqml.qml"));


}

MainWidget::~MainWidget()
{
    delete ui;
}
//SF1446179868590
void MainWidget::on_pushButton_clicked()
{
    QVariant retVal;
    QMetaObject::invokeMethod((QObject*)ui->quickWidget->rootObject(), /* Qml实例 */
                              "execute",         /* 函数名字 */
                              Qt::DirectConnection, /* 连接方式 */
                              Q_RETURN_ARG(QVariant, retVal), /* 标记返回值 */
                              Q_ARG(QVariant, "Hello"), /* 输入参数1 */
                              Q_ARG(QVariant, "world"));/* 输入参数2 */
}

qml文件的实现如下：

import QtQuick 2.0
import QObjectQml.module 1.0

Rectangle {
    width: 360
    height: 360

    signal finished()
    Component.onCompleted: {
        console.log("Hello，Hello")
    }
    //cc++的对象创建，并赋值deviceId
    QObjectQml {
        id: myObject
        /* 设置text属性 */
        deviceId: "12345"
        /* 读取打印text属性 */
        Component.onCompleted: console.log(text)
    }
    function execute(var1, var2) {
         console.log("我是qml函数被调用")//c++
        console.log(var1, var2)//c++调用了qml的此函数。输出结果
        console.log(myObject.deviceId)//并且输出QObjectQml对象的值
        return true;
    }
    Rectangle {
        id: button
        width: 100
        height: 30
        color: "red"
        radius: 5     // 让我们将矩形的角变圆一点，使其更像一个按钮
        anchors.centerIn: parent

        Text {
            id: buttonText
            text: qsTr("Button")
            color: "white"
            anchors.centerIn: parent
        }

        MouseArea {
            //我们将MouseArea设为与其父级（即矩形）一样大。因此，按下按钮上的任意位置都会触发事件
            anchors.fill: parent

            // Exploit the built-in "clicked" signal of the MouseArea component to do something when the MouseArea is clicked.
            //请注意，与信号关联的代码是纯JavaScript。我们可以使用其ID引用任何QML对象
            onClicked: {
                buttonText.text= qsTr("Clicked");
                buttonText.color= "black";
                myObject.deviceId = "ok不ok";
                myObject.funDemo("我靠");//qml点击事件中去调用c++的函数
            }
        }
    }
}

运行结果如下：