Dynamically loading and unloading 2 qml files from cpp

[d_stranz]

If I understand your code correctly, your MainWindow and BaseWindow are both top-level windows (they have no "parent" - they are children of the desktop window). This makes them "sibling" windows, and so you may be able to use the QWidget::stackUnder() method. When you make BaseWindow visible, call MainWindow->stackUnder( BaseWindow ) and vice-versa. I don't know if it will work, but it is worth trying.

[gowreesh]

Thank you for the reply.

I am using QQuickWindow and i am not using QWidget.
I have created a custom window i.e "class CustomWindow : public QQuickWindow {...}"
This CustomWindow only i have used in QML side. and sorry in my first thread i have mentioned ApplicationWindow
So only I am not able to access or pass QQuickWindow to QWidget::stackUnder(QWidget *w).
Requesting you to please let me know if there is any other solution.

[d_stranz]

Sorry, I don't have any other ideas. I do not have much experience with QWindow and QML, so maybe someone else here can give some advice.

[gowreesh]

its OK and thank you very much for replying.
If i don't find any solution i need to go back to that previous method of loading and unloading concept even if it consumes more memory since I don't have any other option.

Could anyone please help me out for the issue I have mentioned above.?????

[d_stranz]

Could anyone please help me out for the issue I have mentioned above.?????

Maybe you should post your current code for loading the windows and switching between them. I am sure it is not the same as the code in your first post and might contain some clues about why it isn't working correctly.

[gowreesh]

Ya sure , I will put my latest code here.
I have designed this below code like if the user launches the application for the first time , then the application will load Mainwindow.qml or basic.qml based on the flag "bSettingMainWindow" .
Next time based on the switch button click from application will load another window (other than first one) and making the first launched qml window visible false.
Once both of them launched once, then 2 windows will play with visibility true or false on click of switch button or signal is emitted.
This below code is working perfectly fine except the window is not coming on top after making visible true. I have tried using raise() and activatewindow() even after that i am facing the same issue.
Please find the code below

//CustomWindow.h
class CustomWindow : public QQuickWindow {
	//Custom QQuick window used in QML 
}
 
 
 
//** windowLoader.hpp   **//
class WindowLoader : public QObject{
    Q_OBJECT
    QQmlApplicationEngine loadQMlEngine;
 
public:
    explicit WindowLoader(QObject * parent = 0);
    void loadWindow();
 
 
public slots:
    void loadMainWindow();
    void loadBasicWindow();
    void connectToMain(QObject *object = nullptr, const QUrl &url = QUrl(""));
    void connectToBasic(QObject *object = nullptr, const QUrl &url = QUrl(""));
 
    private:
};
 
 
 
//** windowLoader.cpp   **//
WindowLoader::WindowLoader(QObject *parent) : QObject(parent) {
 
}
 
//This function will be called only one time during launch
void WindowLoader::loadWindow()  {
	if(bSettingMainWindow){ //this will be from a internal flag, this check is only one time during launch
		connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToBasic(QObject *, const QUrl &)),Qt::QueuedConnection);
		loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
		loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/mainWindow.qml")));
                m_iMainWindowIndex = 0;
                m_iBasicWindowIndex = 1;
	} else {	
		connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToMain(QObject *, const QUrl &)),Qt::QueuedConnection);
		loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
		loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/basic.qml")));		
		m_iMainWindowIndex = 1;
                m_iBasicWindowIndex = 0;
	}
}
 
void WindowLoader::connectToBasic(QObject *object, const QUrl &url) {
    if(object){
        connect(object, SIGNAL(switchToBasicSignal()), this, SLOT(loadBasicWindow()));
    }
}
 
void WindowLoader::connectToMain(QObject *object, const QUrl &url) {
    if(object){
        connect(object, SIGNAL(switchToMainSignal()), this, SLOT(loadMainWindow()));
    }
}
 
void WindowLoader::loadBasicWindow() {	
 
	if(loadQMlEngine.rootObjects().size() <= 2) {
        disconnect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToBasic(QObject *, const QUrl &)));
    }
 
	if(loadQMlEngine.rootObjects().size() < 2) {
        connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToMain(QObject *, const QUrl &)),Qt::QueuedConnection);
        loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
        loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/basic.qml")));
	loadQMlEngine.rootObjects()[m_iMainWindowIndex]->setProperty("visible",false); 
    } else {
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iBasicWindowIndex],"show");        
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iMainWindowIndex],"hide");
        loadQMlEngine.rootObjects()[m_iBasicWindowIndex]->setProperty("visible",true);        
        loadQMlEngine.rootObjects()[m_iMainWindowIndex]->setProperty("visible",false);        
    }
}
 
void WindowLoader::loadMainWindow() {
 
	if(loadQMlEngine.rootObjects().size() <= 2) {
        disconnect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToMain(QObject *, const QUrl &)));
    }
 
	if(loadQMlEngine.rootObjects().size() < 2) {
        connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToBasic(QObject *, const QUrl &)),Qt::QueuedConnection);
        loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
        loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/mainWindow.qml")));
	loadQMlEngine.rootObjects()[m_iBasicWindowIndex]->setProperty("visible",false);  
    } else {        		
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iBasicWindowIndex],"hide");        
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iMainWindowIndex],"show");
        loadQMlEngine.rootObjects()[m_iBasicWindowIndex]->setProperty("visible",false);        
        loadQMlEngine.rootObjects()[m_iMainWindowIndex]->setProperty("visible",true);
    } 
}
 
 
//** main.cpp **//
int main( int argc, char *argv[] ) {
    QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QApplication app(argc, argv);
    qmlRegisterType<CustomWindow>("CNQml", 1, 0, "CustomWindow");
    WindowLoader root;
    root.loadWindow();
    return app.exec();
}

//CustomWindow.h
class CustomWindow : public QQuickWindow {
	//Custom QQuick window used in QML 
}



//** windowLoader.hpp   **//
class WindowLoader : public QObject{
    Q_OBJECT
    QQmlApplicationEngine loadQMlEngine;
 
public:
    explicit WindowLoader(QObject * parent = 0);
    void loadWindow();
 
 
public slots:
    void loadMainWindow();
    void loadBasicWindow();
    void connectToMain(QObject *object = nullptr, const QUrl &url = QUrl(""));
    void connectToBasic(QObject *object = nullptr, const QUrl &url = QUrl(""));
 
    private:
};


 
//** windowLoader.cpp   **//
WindowLoader::WindowLoader(QObject *parent) : QObject(parent) {
 
}

//This function will be called only one time during launch
void WindowLoader::loadWindow()  {
	if(bSettingMainWindow){ //this will be from a internal flag, this check is only one time during launch
		connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToBasic(QObject *, const QUrl &)),Qt::QueuedConnection);
		loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
		loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/mainWindow.qml")));
                m_iMainWindowIndex = 0;
                m_iBasicWindowIndex = 1;
	} else {	
		connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToMain(QObject *, const QUrl &)),Qt::QueuedConnection);
		loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
		loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/basic.qml")));		
		m_iMainWindowIndex = 1;
                m_iBasicWindowIndex = 0;
	}
}
 
void WindowLoader::connectToBasic(QObject *object, const QUrl &url) {
    if(object){
        connect(object, SIGNAL(switchToBasicSignal()), this, SLOT(loadBasicWindow()));
    }
}
 
void WindowLoader::connectToMain(QObject *object, const QUrl &url) {
    if(object){
        connect(object, SIGNAL(switchToMainSignal()), this, SLOT(loadMainWindow()));
    }
}
 
void WindowLoader::loadBasicWindow() {	
	
	if(loadQMlEngine.rootObjects().size() <= 2) {
        disconnect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToBasic(QObject *, const QUrl &)));
    }
	
	if(loadQMlEngine.rootObjects().size() < 2) {
        connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToMain(QObject *, const QUrl &)),Qt::QueuedConnection);
        loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
        loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/basic.qml")));
	loadQMlEngine.rootObjects()[m_iMainWindowIndex]->setProperty("visible",false); 
    } else {
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iBasicWindowIndex],"show");        
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iMainWindowIndex],"hide");
        loadQMlEngine.rootObjects()[m_iBasicWindowIndex]->setProperty("visible",true);        
        loadQMlEngine.rootObjects()[m_iMainWindowIndex]->setProperty("visible",false);        
    }
}
 
void WindowLoader::loadMainWindow() {
	
	if(loadQMlEngine.rootObjects().size() <= 2) {
        disconnect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToMain(QObject *, const QUrl &)));
    }
	
	if(loadQMlEngine.rootObjects().size() < 2) {
        connect(&loadQMlEngine,SIGNAL(objectCreated(QObject *, const QUrl &)),this,SLOT(connectToBasic(QObject *, const QUrl &)),Qt::QueuedConnection);
        loadQMlEngine.rootContext()->setContextProperty( "interface", m_interface );
        loadQMlEngine.load(QUrl(QStringLiteral("qrc:/Qml/mainWindow.qml")));
	loadQMlEngine.rootObjects()[m_iBasicWindowIndex]->setProperty("visible",false);  
    } else {        		
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iBasicWindowIndex],"hide");        
	//QMetaObject::invokeMethod(loadQMlEngine.rootObjects()[m_iMainWindowIndex],"show");
        loadQMlEngine.rootObjects()[m_iBasicWindowIndex]->setProperty("visible",false);        
        loadQMlEngine.rootObjects()[m_iMainWindowIndex]->setProperty("visible",true);
    } 
}
 
 
//** main.cpp **//
int main( int argc, char *argv[] ) {
    QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QApplication app(argc, argv);
    qmlRegisterType<CustomWindow>("CNQml", 1, 0, "CustomWindow");
    WindowLoader root;
    root.loadWindow();
    return app.exec();
}

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// ** mainWindow.qml **//
CustomWindow {
    visible: true
    width: 1200
    height: 800
    title: qsTr("MainWindow")
 
    signal switchToBasicSignal()
 
    Rectangle {
        anchors.fill: parent
        MouseArea{
            anchors.fill: parent
            onClicked: {
                switchToBasicSignal()
            }
        }
    }
}
 
//** basic.qml **//
CustomWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("basicwindow")
 
    signal switchToMainSignal()
 
    Rectangle {
        anchors.fill: parent
        MouseArea{
            anchors.fill: parent
            onClicked: {
                switchToMainSignal()
            }
        }
    }
}

// ** mainWindow.qml **//
CustomWindow {
    visible: true
    width: 1200
    height: 800
    title: qsTr("MainWindow")
 
    signal switchToBasicSignal()
 
    Rectangle {
        anchors.fill: parent
        MouseArea{
            anchors.fill: parent
            onClicked: {
                switchToBasicSignal()
            }
        }
    }
}
 
//** basic.qml **//
CustomWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("basicwindow")
 
    signal switchToMainSignal()
 
    Rectangle {
        anchors.fill: parent
        MouseArea{
            anchors.fill: parent
            onClicked: {
                switchToMainSignal()
            }
        }
    }
}

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