The high-level APIs are designed for applications that have client parts
that run on mobile devices. For these applications, portability across devices
is important. To achieve this portability, the high-level components employ
a high level of abstraction and that provides a pre-defined look and feel.
Generally high-level MIDlets employ common components with clearly defined
features and most low-level applications feature some high-level parts, such
as a main menu created with a List object.
All high-level APIs are derived from the Screen superclass.
When a MIDlet utilizes these classes, the actual implementation takes care
of aspects such as drawing, fonts and navigation. In other words, every Screen object
provides presentation and layout for itself and MIDP applications that use
high-level APIs define only the content. Screen classes
map directly to native Symbian and Series 40 UI
controls.
Low-level key or pointer input is not available in high-level APIs by
default. They can only be accessed via Canvas or CustomItem.
The high-level APIs are:
Alert -
A popup screen to notify the user about an event.
Form -
A screen to which Form Items can be added. The Items are
also considered high-level APIs.
List -
A screen containing a scrollable list of choices.
TextBox -
A screen in which the user can enter or edit text.
For more information about low-level APIs, see section Low-level UI APIs.
For more information about Commands, see section Command handling