C++ 跨多个QML处理信号_C++_Qt_Qml_Signals Slots

C++ 跨多个QML处理信号

c++ qt qml

C++ 跨多个QML处理信号,c++,qt,qml,signals-slots,C++,Qt,Qml,Signals Slots,我刚开始学习Qt编程，在做一个简单的测试应用程序时，我发现自己在与信号和插槽机制作斗争我有两个QML文件：main.QML和grovery.QML 我有一个头文件，用于管理应用程序的信号和插槽： ApplicationManager.h #ifndef APPLICATIONMANAGER_H #define APPLICATIONMANAGER_H #include <QObject> #include <QDebug> class ApplicationManage

我刚开始学习Qt编程，在做一个简单的测试应用程序时，我发现自己在与信号和插槽机制作斗争

我有两个QML文件：main.QML和grovery.QML

我有一个头文件，用于管理应用程序的信号和插槽：

ApplicationManager.h

#ifndef APPLICATIONMANAGER_H
#define APPLICATIONMANAGER_H
#include <QObject>
#include <QDebug>
class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);

signals:
    void newGroceryItem();

public slots:
    void addGroceryItem();
};
#endif // APPLICATIONMANAGER_H

主应用程序main.cpp连接信号，但表示无法找到信号newGroceryItem（），因为它不属于main.qml。因此，我的问题是，如何从辅助qml文件grocery.qml建立到插槽addGroceryItem（）的连接

编辑： 根据要求，以下是main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQuickWindow>
#include <QQmlContext>
#include "applicationmanager.h"
int main(int argc, char *argv[]){
  QGuiApplication app(argc, argv);
  QQmlApplicationEngine engine;
  engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

  QObject *topLevel = engine.rootObjects().value(0);
  QQuickWindow *window = qobject_cast<QQuickWindow *>(topLevel);
  ApplicationManager applicationManager;
  QObject::connect(window, SIGNAL(newGroceryItem()), &applicationManager, SLOT(addGroceryItem()));

  return app.exec();
}

QObject

派生类型的任何方法都可以从QML代码访问，前提是：

用
```
Q_INVOKABLE
```
宏标记的公共方法
一种公共Qt插槽的方法

因此，有两种方法可以访问

addGroceryItem（）

。第一个是使用

Q_INVOKABLE

宏，如下所示：

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
    Q_INVOKABLE void addGroceryItem();
};

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
public slots:
    void addGroceryItem();
};

 int main(int argc, char *argv[]) {
     QCoreApplication app(argc, argv);

     QQmlEngine engine;
     ApplicationManager app;
     engine.rootContext()->setContextProperty("applicationManager", &app);
     QQmlComponent component(&engine, QUrl::fromLocalFile("main.qml"));
     component.create();

     return app.exec();
 }

MouseArea {
    id: okBtnClkd
    anchors.fill: parent
    onClicked: {
        applicationManager.addGroceryItem();
    }
}

第二种方法是使用

公共插槽

，如下所示：

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
    Q_INVOKABLE void addGroceryItem();
};

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
public slots:
    void addGroceryItem();
};

 int main(int argc, char *argv[]) {
     QCoreApplication app(argc, argv);

     QQmlEngine engine;
     ApplicationManager app;
     engine.rootContext()->setContextProperty("applicationManager", &app);
     QQmlComponent component(&engine, QUrl::fromLocalFile("main.qml"));
     component.create();

     return app.exec();
 }

MouseArea {
    id: okBtnClkd
    anchors.fill: parent
    onClicked: {
        applicationManager.addGroceryItem();
    }
}

如果您在C++中创建类对象，则应该将对象设置为<代码>主体.qML >：

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
    Q_INVOKABLE void addGroceryItem();
};

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
public slots:
    void addGroceryItem();
};

 int main(int argc, char *argv[]) {
     QCoreApplication app(argc, argv);

     QQmlEngine engine;
     ApplicationManager app;
     engine.rootContext()->setContextProperty("applicationManager", &app);
     QQmlComponent component(&engine, QUrl::fromLocalFile("main.qml"));
     component.create();

     return app.exec();
 }

MouseArea {
    id: okBtnClkd
    anchors.fill: parent
    onClicked: {
        applicationManager.addGroceryItem();
    }
}

现在，您可以从

main.qml

访问在

main.cpp

中创建的

ApplicationManager

对象，如下所示：

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
    Q_INVOKABLE void addGroceryItem();
};

class ApplicationManager : public QObject
{
    Q_OBJECT
public:
    explicit ApplicationManager(QObject *parent = 0);
public slots:
    void addGroceryItem();
};

 int main(int argc, char *argv[]) {
     QCoreApplication app(argc, argv);

     QQmlEngine engine;
     ApplicationManager app;
     engine.rootContext()->setContextProperty("applicationManager", &app);
     QQmlComponent component(&engine, QUrl::fromLocalFile("main.qml"));
     component.create();

     return app.exec();
 }

MouseArea {
    id: okBtnClkd
    anchors.fill: parent
    onClicked: {
        applicationManager.addGroceryItem();
    }
}

有关更多信息，请参见。

任何

QObject

派生类型的方法，如果是：

用
```
Q_INVOKABLE
```
宏标记的公共方法
一种公共Qt插槽的方法