I'm trying to create a QML extension module using CMake, and I've run into some road blocks. I want to create a QML module including a "plugin", based on my own code rather than an auto-generated plugin stub.
My first question is why? The most important part of a QML module is generally a backing library that contains all the meat to the module: Its C++-based types, its compiled QML code etc. In addition you get a very, very thin plugin that is only there to load the backing library. Except for very specific exceptions, you should always put all your code into the backing library and let qt_add_qml_module generate the plugin. Then you have the choice of either linking the library directly into your application at compile time or loading the plugin at run time. The QML engine is clever enough to avoid the plugin loading overhead if it detects the backing library to be already linked.
Now, the specific exceptions are run time style selection for QtQuick.Controls and image providers. If you are affected by those, you should set NO_GENERATE_PLUGIN_SOURCE, NO_PLUGIN_OPTIONAL, and explicitly specify PLUGIN_TARGET and CLASS_NAME. Then you can use target_sources on the generated plugin target to add your own implementation of the specified plugin class. Be aware that you need to manually reference some symbols from the backing library in order to prevent the linker from "optimizing" the dependency away.
The examples that add custom plugins, unfortunately, all add only an image provider, but no actual QML types. In this case you can get away with making the plugin the same as the backing library. Otherwise you shouldn't do this.
best regards, Ulf _______________________________________________ Interest mailing list Interest@qt-project.org https://lists.qt-project.org/listinfo/interest
