Using QML Modules with Plugins

QML modules may use C++ plugins to expose components defined in C++ to QML applications.

To create a QML module:

  1. Create custom components and place all the .qml files in a directory dedicated to your module. For example: imports\asset_imports.
  2. For Qt Quick UI projects (.qmlproject), specify the path to the directory that contains the module in the .qmlproject file of the application where you want to use the module as a value of the importPaths variable. For example importPaths: [ "imports", "asset_imports" ].
  3. Create a qmldir file for your module and place it in the module directory. For more information, see Module Definition qmldir Files.
  4. Create a qmltypes file, as instructed in Generating Type Description Files.
  5. Create a directory named designer in your module directory.
  6. Create a .metainfo file for your module and place it in the designer directory. Use a metainfo file delivered with Qt, such as qtquickcontrols2.metainfo, as an example.
  7. Import the module into the project, as instructed in Importing QML Modules.

Generating Type Description Files

When registering QML types, make sure that the QML module has a plugins.qmltypes file. Ideally, it should be located in the same directory as the qmldir file. The qmltypes file contains a description of the components exported by the module's plugins and is loaded by Qt Creator when the module is imported.

For more information, see Type Description Files.

Dumping Plugins Automatically

If a module with plugins lacks the qmltypes file, Qt Creator tries to generate a temporary file itself by running the qmldump program in the background. However, this automatic dumping is a fallback mechanism with many points of failure and you cannot rely upon it.

Importing QML Modules

By default, Qt Creator will look in the QML import path of Qt for QML modules.

If you use qmake and your application adds additional import paths that Qt Creator should use, specify them using QML_IMPORT_PATH in the .pro file of your application: QML_IMPORT_PATH += path/to/module.

If you use CMake, add the following command to the CMakeLists.txt file to set the QML import path:

set(QML_IMPORT_PATH ${CMAKE_SOURCE_DIR}/qml ${CMAKE_BINARY_DIR}/imports CACHE STRING "" FORCE)

The import path affects all the targets built by the CMake project.

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