Application framework classes in Architecture of a UIQ application

The framework requires that an application define four objects: an application, a document, an application UI, and one or more application views.

High-level architecture of a UIQ application. The grey classes are those provided in the UIQ platform. The green classes are those created by the application developer.

The green classes are written by the application developer. The CQikAppUi,CQikDocument and CQikApplication classes are provided by Qikon. The CEik classes are framework classes supplied by the Uikon Core API. CCoeControl and CCoeAppUi belong to the UI Control Framework. CApaDocument and CApaApplication belong to the Application Architecture.

The application class (base classes CEikApplication and CApaApplication) defines the properties of the application, such as UID and caption, and creates a new document. In Qikon it is extended by CQikApplication; UIQ applications must inherit from this class.

See How to create the application class.
The document class (base classes CEikDocument and CApaDocument) represents the data model for the application. In Qikon it is extended by CQikDocument to provide support for closing down applications in low memory situations and automatically saving data; UIQ applications must inherit from this class.

See How to create the document class.
The App UI (base classes CEikAppUi and CCoeAppUi) is the central user interface class. It creates and owns views to display the application data, and handles the commands that the view passes on from input from standard controls such as menus. In Qikon it is extended by CQikAppUi which provides category support; UIQ applications must inherit from this class.

See How to create the application UI class.
The application view, which inherits from CQikViewBase or CQikMultiPageViewBase (depending on the type of page), displays the application data on the screen and allows the user to interact with it. Complex applications have more than one way of displaying their data, and so more than one view. A view architecture is implemented to handle view switching functionality. Inheriting from CQikViewBase or CQikMultiPageViewBase is not required, but is highly recommended.

See How to create the application view class for the definition and implementation of a minimal view class.