An error occurred when registering a C++ class using QML_ELEMENT: QQmlApplicationEngine failed to load component

I wrote a simple example while learning QML and CMake. The main purpose is to demonstrate how to use `qt_add_qml_module` and how to register C++ classes in QML.

the key code is as follows:

**//CMakeLists.txt** add_subdirectory(mybackend) qt_add_executable(appMyMain main.cpp ) qt_add_qml_module(appMyMain URI "MainApp" RESOURCE_PREFIX /mycompany/mainapp VERSION 1.0 QML_FILES Main.qml ) target_link_libraries(appMyMain PRIVATE Qt6::Quick BackendLib) qt_finalize_executable(appMyMain) **//main.cpp** int main(int argc, char *argv[]) { QGuiApplication app(argc, argv); QQmlApplicationEngine engine; engine.addImportPath(":/mycompany/imports"); const QUrl url(u"qrc:/mycompany/mainapp/Main.qml"_qs); 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(); } **//Main.qml** import QtQuick import QtQuick.Controls import MyCompany.Backend **//mybackend/CMakeLists.txt** qt_add_library(BackendLib STATIC) set_target_properties(BackendLib PROPERTIES AUTOMOC ON) qt_add_qml_module(BackendLib URI "MyCompany.Backend" RESOURCE_PREFIX /mycompany/mainapp VERSION 1.0 SOURCES MyBackend.h MyBackend.cpp ) target_link_libraries(BackendLib PRIVATE Qt6::Quick) **//mybackend/Mybackend.h** #include <QObject> #include <QtQml> class MyBackend : public QObject { Q_OBJECT QML_ELEMENT Q_PROPERTY(QString userName READ userName WRITE setUserName NOTIFY userNameChanged)

Then I received the following error message:

QQmlComponent: attempted to load via a relative URL 'qrc:qt/qml/mycompany/mainapp/Main.qml' in resource file system. This is not fully supported and may not work QQmlApplicationEngine failed to load component qrc:qt/qml/mycompany/mainapp/Main.qml: No such file or directory

I have already asked the AI, but it didn't provide me with any effective solutions.