How to create a custom QML item on Qt6+CMake ?

r3d9u11

Hello. I'm trying to create some simple custom Qt6 item with C++ /CMake for QML.
But QML doesn't see my new item.
Could somebody explain, what's wrong?

the folder of item is "lib/MyCustomQmlItem"

lib/MyCustomQmlItem/include/MyCustomQmlItem.hpp

#include <QQuickItem>
class MyCustomQmlItem: public QQuickItem
{
    Q_OBJECT
    QML_ELEMENT
public:
    explicit MyCustomQmlItem(QQuickItem* parent = 0);
};

lib/MyCustomQmlItem/src/MyCustomQmlItem.cpp

#include "MyCustomQmlItem.hpp"
MyCustomQmlItem::MyCustomQmlItem(QQuickItem* parent):
    QQuickItem{parent}
{
    qDebug() << "Hello from MyCustomQmlItem";
}

lib/MyCustomQmlItem/CMakeLists.txt

project(MyCustomQmlItem)

SET(CMAKE_AUTOMOC ON)
SET(CMAKE_AUTOUIC ON)
SET(CMAKE_AUTORCC ON)

add_library(MyCustomQmlItem "src/MyCustomQmlItem.cpp" "include/MyCustomQmlItem.hpp")

qt_add_qml_module(
  MyCustomQmlItem
  URI example.MyCustomQmlItem
  VERSION 1.0
  SOURCES
    "src/MyCustomQmlItem.cpp"
    "include/MyCustomQmlItem.hpp")

target_include_directories(MyCustomQmlItem PUBLIC "include")

find_package(Qt${QT_VERSION_MAJOR} COMPONENTS Core Quick REQUIRED)

target_compile_definitions(MyCustomQmlItem
  PRIVATE $<$<OR:$<CONFIG:Debug>,$<CONFIG:RelWithDebInfo>>:QT_QML_DEBUG>)
target_link_libraries(MyCustomQmlItem
  PRIVATE Qt${QT_VERSION_MAJOR}::Core Qt${QT_VERSION_MAJOR}::Quick)

main CMakeLists.txt:

...
SET(CMAKE_AUTOMOC ON)
SET(CMAKE_AUTOUIC ON)
SET(CMAKE_AUTORCC ON)
...
qt_add_executable(${OUTPUT_NAME} ${PROJECT_SOURCES} )
qt_add_qml_module(${OUTPUT_NAME} URI "main" VERSION 1.0 QML_FILES "main.qml")
...
add_subdirectory("lib/MyCustomQmlItem")
target_link_libraries(${OUTPUT} MyCustomQmlItem)
include_directories("lib/MyCustomQmlItem/include")

is it right usage of qt_add_qml_module in my cmake ?

maybe somebody has an example of custom module for Qt6 + CMake (all examples what I found only for Qt5 and(or) Qbs).

Thanks!

r3d9u11

Ok. I've found example of CMakeLists.txt in Qt6 repo.

it works if apply all sources of sub-item to main executable
like

qt_add_executable(chapter1-basics
    main.cpp piechart.cpp piechart.h
)

but is there way to separate sub-item as external library ?
something like a

qt_add_executable(chapter1-basics
    main.cpp
)
...
qt_add_library(lib_piechart piechart.cpp piechart.h)
target_link_libraries(lib_piechart PUBLIC Qt::Core Qt::Gui Qt::Qml Qt::Quick)
target_link_libraries(chapter1-basics PRIVATE lib_piechart)