By using the jog-dial button instead of the virtual keyboard on the Sonu Ericsson P910 series you can design games with more action. The use of the jog-dial is also a great feature if you want to develop an application for a bigger screen and avoid using the virtual keyboard.

You can access the jog-dial using J2ME, PersonalJava and C++.

The jog-dial in not a "true" 5-way navigation device, as the "up" and "down" can't be sustained by holding the dial. If the jog-dial is rolled up or down, the events generated represent the "up" and "down" game keys being rapidly pressed and released.

The dial's "towards" and "away" actions are mapped to the "right" and "left" game keys. These can be sustained by holding the dial. However, if the towards action (right) is pressed for a few seconds, this will switch the game MIDlet out of focus revealing the applications menu for the user. When the application is brought back into focus, the startApp method is called. In short, be careful when using the jog dial for left and right game actions.

Download the example application below to see the events triggered by the jog-dial.

Download jog-dial example>>