Feedback needed: QML is this the right way to link other QML Files?

StudentScripter

So my goal was to seperate my .qml files from the Main.qml by creating a subfolder called mymodules/ which contains my other .qml files as a library. But im not sure if my CMakeLists.txt are the most optimal. Can anyone check and give me feeback? <3 Thanks

My structure looks like this:

mymodules CMakeLists.txt:

cmake_minimum_required(VERSION 3.16)
project(mymodules VERSION 1.0 LANGUAGES CXX)

find_package(Qt6 REQUIRED COMPONENTS Quick)

qt_add_library(mymodules STATIC)  # <--- STATIC statt SHARED/PLUGIN

qt_add_qml_module(mymodules
    URI mymodules                 # entspricht: import mymodules 1.0
    VERSION 1.0
    QML_FILES
        Buttons.qml
    RESOURCE_PREFIX /            # wichtig: sonst wird es zur Laufzeit nicht gefunden
)

target_link_libraries(mymodules
    PRIVATE Qt6::Quick
)

Main CMakeLists.txt:

cmake_minimum_required(VERSION 3.16)

project(QmlLibraryTest VERSION 0.1 LANGUAGES CXX)

set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)

find_package(Qt6 REQUIRED COMPONENTS Quick)

qt_standard_project_setup(REQUIRES 6.8)

qt_add_executable(appQmlLibraryTest
    main.cpp
)

qt_add_qml_module(appQmlLibraryTest
    URI QmlLibraryTest
    VERSION 1.0
    QML_FILES
        Main.qml
)




# Qt for iOS sets MACOSX_BUNDLE_GUI_IDENTIFIER automatically since Qt 6.1.
# If you are developing for iOS or macOS you should consider setting an
# explicit, fixed bundle identifier manually though.
set_target_properties(appQmlLibraryTest PROPERTIES
#    MACOSX_BUNDLE_GUI_IDENTIFIER com.example.appQmlLibraryTest
    MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
    MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
    MACOSX_BUNDLE TRUE
    WIN32_EXECUTABLE TRUE
)




# Baue und installiere das Sub‑Modul mit
add_subdirectory(mymodules)


target_link_libraries(appQmlLibraryTest
    PRIVATE Qt6::Quick
    mymodules  # <-- statische lib (ohne "plugin")

)

include(GNUInstallDirs)
install(TARGETS appQmlLibraryTest
    BUNDLE DESTINATION .
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

main.cpp:

#include <QGuiApplication>
#include <QQmlApplicationEngine>


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

    QQmlApplicationEngine engine;
    QObject::connect
        &engine,
        &QQmlApplicationEngine::objectCreationFailed,
        &app,
        []() { QCoreApplication::exit(-1); },
        Qt::QueuedConnection);
    engine.loadFromModule("QmlLibraryTest", "Main");

    return app.exec();
}

@Pl45m4

Pl45m4

@StudentScripter

why you tagged me, I'm not an expert in QML?
But I would put all qml files in the qt resource system.

StudentScripter

@Pl45m4 Thought you'd may have some experience regarding the cmake aspect. :D But nevermind.

Deymos

Hello, i'm trying to do something similar, but only with qt_add_qml_module, check out this:
https://github.com/Deymoss/MoneyTogether/tree/master/modules/UI
and this
https://forum.qt.io/topic/162027/correct-way-to-make-qml-modules-qt-6.5-6.9/14
So far, I have not come to a solution to the problem, but I think I will solve it in the next week, thanks a lot to Mike Trahearn, he pushed this question in the qt expert community and said that he has an example that is currently still in progress, so we need to wait and there will be an answer.

StudentScripter

@Deymos Well gonna have a look at that, but nevertheless my approach posted above does work without error utilizing qt_add_qml_module but im not sure if its the best approach or has any potential errors. Thats why i was asking.

Deymos

@StudentScripter
Yes, this approach that you provided will work without problems, but I want to try to do it without

qt_add_library(mymodules STATIC)

so that there is not a lot of junk in the project tree, and it turns out to be possible. But we have to wait

JKSH

Hi @StudentScripter, yes in general your structure is fine.

I just noticed something strange::

RESOURCE_PREFIX /            # wichtig: sonst wird es zur Laufzeit nicht gefunden
...
mymodules  # <-- statische lib (ohne "plugin")

I would remove RESOURCE_PREFIX / and change mymodules to mymodulesplugin. Does it still work for you?

StudentScripter

@JKSH removing RESOURCE_PREFIX / is no problem, works still fine, thanks. :D

However do you mean changing all mymodules mentions to mymodulesplugin or only this one? Cause when changing only one it gives me errors.

Here are all my files:

CMakeLists.txt inside mymodules subfolder:

cmake_minimum_required(VERSION 3.16)
project(mymodules VERSION 1.0 LANGUAGES CXX)

find_package(Qt6 REQUIRED COMPONENTS Quick)

qt_add_library(mymodules STATIC)  # <--- STATIC instead of SHARED/PLUGIN

qt_add_qml_module(mymodules
    URI mymodules                 # entspricht: import mymodules 1.0
    VERSION 1.0
    QML_FILES
        Buttons.qml
        Qmld.qml
        XP3DDebugViewer.qml
    SOURCES
        Myhelper.hpp
        Myhelper.cpp
)

set_target_properties(mymodules PROPERTIES
    QT_QML_MODULE TRUE
)


target_link_libraries(mymodules
    PRIVATE Qt6::Quick
)

Main CMakeLists.txt:

cmake_minimum_required(VERSION 3.16)

project(QmlLibraryTest VERSION 0.1 LANGUAGES CXX)

set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)


find_package(Qt6 REQUIRED COMPONENTS Quick)

qt_standard_project_setup(REQUIRES 6.8)

qt_add_executable(appQmlLibraryTest
    main.cpp
)

qt_add_qml_module(appQmlLibraryTest
    URI QmlLibraryTest
    VERSION 1.0
    QML_FILES
        Main.qml
)




# Qt for iOS sets MACOSX_BUNDLE_GUI_IDENTIFIER automatically since Qt 6.1.
# If you are developing for iOS or macOS you should consider setting an
# explicit, fixed bundle identifier manually though.
set_target_properties(appQmlLibraryTest PROPERTIES
#    MACOSX_BUNDLE_GUI_IDENTIFIER com.example.appQmlLibraryTest
    MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
    MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
    MACOSX_BUNDLE TRUE
    WIN32_EXECUTABLE TRUE
)




# Baue und installiere das Sub‑Modul mit
add_subdirectory(mymodules)


target_link_libraries(appQmlLibraryTest
    PRIVATE Qt6::Quick
    mymodules  # <-- statische lib (ohne "plugin")

)

include(GNUInstallDirs)
install(TARGETS appQmlLibraryTest
    BUNDLE DESTINATION .
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

In Main.qml i import it as:


import mymodules 1.0


               Qmld {
                    id: krass
                    anchors.fill: parent
                }

                
                Buttons {
                    id: neubtn
                    anchors.bottom: parent.bottom
                    anchors.right: parent.right
                }

StudentScripter

Also another question what to do if i wanted to add another subfolder inside my
mymodules/ directory? Lets say: mymodules/extras

JKSH

@StudentScripter said in Feedback needed: QML is this the right way to link other QML Files?:

removing RESOURCE_PREFIX / is no problem, works still fine, thanks. :D

Good to hear, that's what I expected :) There were some changes in Qt 6.5 to make things easier, so you should no longer need to specify RESOURCE_PREFIX unless you want some unconventional structure (which is not recommended)

However do you mean changing all mymodules mentions to mymodulesplugin or only this one?

I meant only one:

target_link_libraries(appQmlLibraryTest
    PRIVATE Qt6::Quick
    mymodulesplugin  # <-- Like this

)

Cause when changing only one it gives me errors.

Can you please share the full error message? Without it, it makes it hard to troubleshoot for you.

@StudentScripter said in Feedback needed: QML is this the right way to link other QML Files?:

Also another question what to do if i wanted to add another subfolder inside my
mymodules/ directory? Lets say: mymodules/extras

You could create a new QML module (in mymodules/extras/CMakeLists.txt)