.qmltypes not found by QtCreator for custom Qml Components

[AlexanderF]

I'm having trouble getting the qmldir and the qmlplugindump / .qmltypes infrastructure to work in my QtCreator with Qt 5.12.3

I have a folder QmlResources that builds a library of the same name (CMake based).
Inside it there is a /qml folder containing a CustomButton.qml and a qmldir. Both are added to a qml.qrc located in the main folder. There is also a /src folder containing a class based on QQmlExtensionPlugin, so the result is

/QmlResources
        CMakeLists.txt
        qml.qrc
    /qml/
        CustomButton.qml
        qmldir
    /src/
        QmlResources.h

The qml.qrc looks like this

<RCC>
    <qresource prefix="/QmlResources">
        <file>qml/CustomButton.qml</file>
        <file>qml/qmldir</file>
    </qresource>
</RCC>

qmldir:

module QmlResources
CustomButton 0.1 CustomButton.qml
plugin QmlResources

CustomButton.qml

import QtQuick 2.6
import QtQuick.Controls 1.4
Button {
    // some button stuff
}

QmlResources.h

class CustomQmlResources final: public QQmlExtensionPlugin {
    Q_OBJECT
    Q_PLUGIN_METADATA(IID "somestring")

public:
    CustomQmlResources ();
    void registerTypes(const char * uri) override {
        qmlRegisterType(QUrl("qrc:/QmlResources/qml/CustomButton.qml"), uri, MAJOR, MINOR, "CustomButton");
    };
};

Now QtCreator is telling me when I import QmlResources 0.1 in a QML file:
"QML module does not contain information about components contained in plugins"

When I try to run "qmlplugindump.exe QmlResources 0.1" in the qml folder I get

QQmlComponent: Component is not ready
file:///typelist.qml:3:1: module "QmlResources" is not installed

I've read all of the documentation about qmldirs and plugins multiple times and I can't figure out how this is supposed to work

[AlexanderF]

I made some progress and I was able to generate a .qmltypes file.
Some issues I had to fix:

• qml.qrc needed to be in the same folder as the qmls and qmldir so the path doesn't need /qml/
• The registerType has to use the now shorter url, eg qmlRegisterType(QUrl("qrc:/QmlResources/CustomButton.qml"), uri, MAJOR, MINOR, "CustomButton");
• With the cxx plugin it seems to be unnecessary adding the CustomButton to the qmldir. What needs to be there is "module QmlResources" and "plugin QmlResources"
• The qmlplugindump.exe needs to be run inside the release folder with the release.dlls, otherwise it won't find required dependencies, eg "/loaddependencies.qml:2:1: module "QtQuick" plugin "qtquick2plugin" not found"

After generating the .qmltypes file I added it to the /qml/ folder and put this in the qmldir "typeinfo qmlresources.qmltypes". Unfortunately it's still trying to auto generate and failing due to the QtQuick dependency it fails to find.

[AlexanderF]

I got it to work! What was missing was installing the .qmltypes file into the build folder of QmlResources together with the qmldir, so both can be found by the QtCreator