Motorola C381P 用户手册

下载
页码 130
18 
Lightweight
 Windowing Toolkit  
 
84 
18 
Lightweight Windowing Toolkit  
LWT integrate with the LCDUI API within the MIDP and enhance the capabilities to 
include a component-level API through which developers can control the contents and 
layout of their screens. These components are graphical user interface elements such as 
buttons, check boxes, text fields, images, etc. LWT also allow developers to create new 
imaginative components or change the look and feel of existing components. 
Those MIDlets taking advantage of the added capabilities of LWT will only run on those 
handsets that incorporate the LWT LOC. 
LWT extends the MIDP class hierarchy by extending the LCDUI Canvas class. The 
ComponentScreen is a subclass of Canvas, which means it can be easily added to a 
MIDP implementation and minimize dependencies and maintenance overhead. This also 
allows standard MIDlets to mix both MIDP screens and LWT screens in their MIDlets. 
LWT is designed to use MIDP low-level graphics routines exclusively, which adds to the 
ease of implementation. Although no device-specific modifications are required, an LWT 
implementation may be tailored to match the rest of the device’s user interface. The text 
components in LWT may be integrated with the device’s data entry mechanisms, such as 
handwriting recognition or predictive keypad input.  
LWT implementation requires the handset to be MIDP compliant and have approximately 
30KB of flash memory. 
LWT does not expose any additional native interfaces and only relies on mechanisms 
specified by MIDP 1.0. LWT can be safely exposed to untrusted MIDlets. 
Once LWT is implemented, the LWT TCK must be completed and pass successfully.