How to open an Android app in a QML app?

[a.burks]

Is it possible to open an Android app with a Qt.openUrlExternally() command, maybe with a specific protocol, or do I have to implement a JNI solution?

I found a quire old project at GitHub: https://github.com/AndroidCpp/qmlandroidlauncher

I seem to work, but my app exits, because I seem to make something wrong in the main C++ class.

The Qt Android app template suggests the following code:

QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

QGuiApplication app(argc, argv);

QQmlApplicationEngine engine;
const QUrl url(QStringLiteral("qrc:/main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                 &app, [url](QObject *obj, const QUrl &objUrl) {
    if (!obj && url == objUrl)
        QCoreApplication::exit(-1);
}, Qt::QueuedConnection);

engine.load(url);

return app.exec();

The Github projects uses the following code, wherein I replaced QApplication by QGuiApplication:

QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
QQuickView viewer;
viewer.setResizeMode(QQuickView::SizeRootObjectToView);

BackEnd backend(viewer);

viewer.rootContext()->setContextProperty("backEnd", &backend);

QObject::connect(viewer.engine(), &QQmlEngine::quit, &viewer, &QWindow::close);
viewer.setSource(QUrl("qrc:/main.qml"));
viewer.show();
return app.exec();

The app shows two warning before it is closed:

QQuickView does not support using windows as a root item.
If you wish to create your root window from QML, consider using QQmlApplicationEngine instead.

[a.burks]

@j-hilk Thanks. I know the Qt Android Extras. Unfortunately I don't know how to make the C++ class available. I used the quoted approach of the example project, but this causes a conflict with the root QML type ApplicationWindow in my main.qml file.

Edit: I have now implemented a different approach than the official example of Qt Android Extras: The default integration approach, that is described herer: https://doc.qt.io/qt-5/qtqml-cppintegration-topic.html. This seem to work, but I have to make further tests.

2nd Edit: Now it works

[J.Hilk]

hi @a-burks
as far as I know, that is going to require nativ calls, but there is the QtAndroid module
https://doc.qt.io/qt-5/qtandroid.html

that allows you to make native calls from qt, easily enough

[a.burks]

@j-hilk Thanks. I know the Qt Android Extras. Unfortunately I don't know how to make the C++ class available. I used the quoted approach of the example project, but this causes a conflict with the root QML type ApplicationWindow in my main.qml file.

Edit: I have now implemented a different approach than the official example of Qt Android Extras: The default integration approach, that is described herer: https://doc.qt.io/qt-5/qtqml-cppintegration-topic.html. This seem to work, but I have to make further tests.

2nd Edit: Now it works