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diff --git a/examples/qml/referenceexamples/coercion/doc/coercion.rst b/examples/qml/referenceexamples/coercion/doc/coercion.rst new file mode 100644 index 000000000..2ccdaeb4f --- /dev/null +++ b/examples/qml/referenceexamples/coercion/doc/coercion.rst @@ -0,0 +1,35 @@ +.. _qml-inheritance-and-coercion-example: + +Extending QML - Inheritance and Coercion Example +================================================ + +This example builds on the :ref:`qml-adding-types-example` and the +:ref:`qml-object-and-list-property-types-example` . + +The Inheritance and Coercion Example shows how to use base classes to assign +types of more than one type to a property. It specializes the Person type +developed in the previous examples into two types - a ``Boy`` and a ``Girl``. + +Declare Boy and Girl +-------------------- + +The Person class remains unaltered in this example and the Boy and Girl C++ +classes are trivial extensions of it. The types and their QML name are +registered with the QML engine. + +As an example, the inheritance used here is a little contrived, but in real +applications it is likely that the two extensions would add additional +properties or modify the Person classes behavior. + +Running the Example +------------------- + +The BirthdayParty type has not changed since the previous example. The +celebrant and guests property still use the People type. + +However, as all three types, Person, Boy and Girl, have been registered with the +QML system, on assignment QML automatically (and type-safely) converts the Boy +and Girl objects into a Person. + +The main.py file in the example includes a simple shell application that +loads and runs the QML snippet shown below. |