- Qt 6.9
- Qt Qml
- C++ Classes
- QQmlExtensionPlugin
- Qt 6.9.1 Reference Documentation

# QQmlExtensionPlugin Class

The QQmlExtensionPlugin class provides an abstract base for custom QML extension plugins with custom type registration functions. More...

Header: | `#include <QQmlExtensionPlugin>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Qml)` `target_link_libraries(mytarget PRIVATE Qt6::Qml)`
qmake: | `QT += qml`
Inherits: | QObject

- List of all members, including inherited members
- QQmlExtensionPlugin is part of Plugin Classes.

## Public Functions

`(since 6.0)` virtual void | unregisterTypes()

## Reimplemented Public Functions

virtual void | initializeEngine(QQmlEngine *engine, const char *uri) override
virtual void | registerTypes(const char *uri) override = 0

## Detailed Description

Note: If you need to write a plugin manually (which is rare) you should always use QQmlEngineExtensionPlugin. QQmlExtensionPlugin only provides the registerTypes() and unregisterTypes() functions in addition. You should not use them, but rather declare your types with QML_ELEMENT and friends and have the build system take care of the registration.

## Member Function Documentation

### `[override virtual]` void QQmlExtensionPlugin::initializeEngine(QQmlEngine *engine, const char *uri)

Initializes the extension from the uri using the engine. Here an application plugin might, for example, expose some data or objects to QML, as context properties on the engine's root context.

### `[override pure virtual]` void QQmlExtensionPlugin::registerTypes(const char *uri)

Registers the QML types in the given uri. Subclasses should implement this to call qmlRegisterType() for all types which are provided by the extension plugin.

The uri is an identifier for the plugin generated by the QML engine based on the name and path of the extension's plugin library.

### `[virtual, since 6.0]` void QQmlExtensionPlugin::unregisterTypes()

Override this method to unregister types manually registered in registerTypes.

This function was introduced in Qt 6.0.