The MIDP GUI APIs
Because of the issues outlined earlier, the MIDP contains its own abbreviated GUI, which is much different from AWT. The MIDP GUI consists of both high-level and low-level APIs, each with their own set of events. This chapter discusses and shows examples of using objects from both the high-level and low-level APIs. Handling events from APIs, however, is deferred to the next chapter.
The high-level API is designed for applications where portability
between mobile information devices is important. To achieve
portability, the API employs a high-level abstraction and gives you
little control over its look and feel. For example, you cannot define
the visual appearance (shape, color, or font) of the high-level
components. Most interactions with the components are encapsulated by
the implementation; the application will not be aware of them.
Consequently, the underlying implementation does the necessary
adaptation to the device’s hardware and native user interface
style. Classes that implement the high-level API all inherit the
javax.microedition.lcdui.Screen class.
The low-level API provides little abstraction. It is designed for
applications that need precise placement and control of graphic
elements, as well as access to low-level input events. This API gives
the application full control over what is being drawn on the display.
The javax.microedition.lcdui.Canvas and
javax.microedition.lcdui.Graphics classes implement the low-level API. However, we should point out ...