[kbottner]

Any J2ME developers out there who can point me in the right direction on where I can register a TrackwheelListener when developing a J2ME MIDlet.

Thanks in advance,

Keith

[jonberry]

I'm not sure that mixing the MIDlet UI with the BlackBerry UI is such a good idea.

What are you trying to accomplish?

Jon

[stefan]

You cannot mix MIDlet and BlackBerry UI. What you can do is to listen for the events generated by the wheel scrolling up or down. Unfortunatelly the wheel click does not generate an event in MIDlet implementation.

[kbottner]

We are porting a game to the Blackberry series and we would of course like to use as much of the native method of navigation as possible. Since we need to create a MIDlet and use GameCanvas we would need access to the track wheel "push"/"click" event. It appears that TrackwheelListener would fit the bill, however, we have been unsuccessful finding a RIM J2ME extension that allows registering a listener for this particular event.

You are correct BTW, the scrolling of the track wheel does get convert into UP, DOWN, LEFT, RIGHT events but we seem to never receive the "click".

Anybody have any other ideas? Or is the general consensus that you cannot do it through a MIDlet but would have to do it through an UI/Application.

Keith

[eradis]

You can directly add the TrackwheelListener to any class that implements TrackwheelListener interface.

The TrackwheelListener is in the net.rim.device.api.system package not the net.rim.device.api.ui package.

[kbottner]

Thanks for correcting me on where the TrackwheelListener lives, but where would I register a class that implements the TrackwheelListener interface? The problem is not implementing the interface, the problem is that I cannot find a way to register the listener to receive the events.

Keith

[eradis]

To add the TrackwheelListener use the following code (from within the class in the constructor implementing TrackwheelListener - probably Canvas or GameCanvas).

Application.getApplication.addTrackwheelListener(this)

You could also do it from outside of the class but you would be required to have an instance of the class to reference.

You could then perform mapping to your existing event handlers (that are pure MIDP).

[kbottner]

Works like a champ, thanks for sharing the info.

Keith

[mtnlife@speakeasy.net]

I understood this thread until how to register the TrackwheelListener.

Application.getApplication.addTrackwheelListener(t his);

Where did the Application class come from? Was the application created as a UIApplication instead of a MIDlet? If so how was the display accessed to set up the GameCanvas. What bridged standard J2ME and the RIM stuff? I have some nice GameCanvas operations I would like to keep but need the trackwheel click event.

[kbottner]

Basically you just need to have one of your classes implement TrackwheelListener and potentially KeyListener as well, then call the static methods to register the track wheel listener as below:

Application.getApplication().addTrackwheelListener (this);
Application.getApplication().addKeyListener(this);

Once I did this I received all track wheel and key listening notifications. If you have any other issues let me know and I will see if I can help.

Keith

[mtnlife@speakeasy.net]

I did a rookie move and was trying to do the registration with:

Application.getApplication.addTrackwheelListener(t his);

Once I did the correct call:

Application.getApplication().addTrackwheelListener (this);

In came the event.

You guys saved me a bunch of time and this should make handset porting much easier.