If you add additional attributes that change how the screen is divided
(e.g., Nokia-MIDlet-On-Screen-Keypad adds a virtual keypad to
the screen), there are even more combinations that can be used by your
MIDlet. Adding the following JAD attributes adds the virtual keypad and
enables orientation switches (see Figure 4.13):
Figure 4.13 Scaling, orientation switches and virtual keypad
An additional JAD attribute in S60 5th Edition, Nokia-MIDlet-App-
Orientation , allows MIDlets to force either portrait or landscape
UI orientation. MIDlets need to add the JAD attribute with the value
portrait or landscape . If the attribute is undefined, the MIDlet is
required to support dynamic orientation switching.
4.8.2 Generic Solutions
The screen and display parameters are the size and the color depth.
MIDlets should never assume any specific screen size. Instead, they
should query the size of the display and adjust their view accordingly.