Thought of by helloworld

For a Symbian GUI application, four classes must be implemented:

(1) Application class (helloworldapp. cpp)

This class is used to define the properties of an application, generate new blank documents, and pass uid information.

(2) document class (helloworlddocument. cpp)

This class indicates the data mode of the application. It is responsible for saving and restoring the data of the application and creating the user UI interface of the application.

(3) application UI Interface Class (helloworldappui. cpp)

This class is completely invisible. It creates an application view and processes 32-bit commands such as menus.

(4) Application View class (helloworldcontainer. cpp)

This is a specific control class, which aims to display application data on the screen and allow user interaction.

Through the functions of these classes, we can conclude that the startup process of a program is as follows:

Helloworldapp. cpp -----> helloworlddocument. cpp ------> helloworldappui. cpp ------> helloworldcontainer. cpp