Extending QML - Extension Objects Example

Extension Objects.

This example builds on:

• Extending QML - Adding Types Example

Shows how to use qmlRegisterExtendedType() to provide an extension object to a QLineEdit without modifying or subclassing it.

Firstly, the LineEditExtension class is registered with the QML system as an extension of QLineEdit:

      qmlRegisterExtendedType<QLineEdit, LineEditExtension>("People", 1,0, "QLineEdit");

The QML engine then instantiates a QLineEdit:

      QQmlEngine engine;
      QQmlComponent component(&engine, QUrl("qrc:example.qml"));
      QLineEdit *edit = qobject_cast<QLineEdit *>(component.create());

In QML, a property is set on the line edit that only exists in the LineEditExtension class:

  QLineEdit {
      leftMargin: 20
  }

The extension type performs calls on the QLineEdit that otherwise will not be accessible to the QML engine.

Files:

• referenceexamples/extended/example.qml
• referenceexamples/extended/extended.pro
• referenceexamples/extended/extended.qrc
• referenceexamples/extended/lineedit.cpp
• referenceexamples/extended/lineedit.h
• referenceexamples/extended/main.cpp