In this chapter the architecture of a Series 60 GUI application has been discussed. Series 60 offers three design choices with regard to UI development ”namely, Avkon View-Switching Architecture, Traditional Symbian OS Control-Based Architecture and Dialog-Based Architecture, and each of these has been considered . You should now understand the benefits and drawbacks of each approach and be able to create an application using your chosen option, deriving from the appropriate framework classes.
So that you get into good habits as soon as you start writing Series 60 applications, some important development principles have been explained. Separating the UI from the engine allows you to develop both components independently. It also means that porting your application to multiple Symbian OS platforms should be simple. The ECom framework was introduced as a method of implementing DLL plug-ins, and it should be considered if you are writing a DLL for a Series 60 2.x device. Although this would be overkill for most UI applications, it does provide a means of dynamic expandability, where new implementations of interfaces can be added (as a separate library) at a later date, without the need for changes to client code.
Making your application available to an international market may not be an immediate consideration for you, but if you follow the Internationalization guidelines outlined in this chapter, you will be able to easily add support for other languages.
You are now in a position to create a simple GUI application. When you tackle more complex projects, you will be able to draw upon the ideas in this chapter to produce efficient, well-designed applications. The next chapter supplements the lessons learned here by showing you how to develop UI controls. These two chapters, combined, provide enough information for you to begin developing real applications.