Java – Read tilt sensor from live wallpaper

I am making my first live wallpaper. I started with the code in the example CubeWallpaper and modified it. So far so good, I’m now drawing my own, completely different animation graphics.

I now want my graphics to respond to the tilt of my phone. I previously implemented the tilt sensor in a non-wallpaper app. However, when I try to include my skew code into the wallpaper, the onSensorChanged() method never seems to be called – at least my log messages never appear in logcat.

One thing I’m not sure about is where to attach implements SensorEventListener. Should it be my class that extends the WallpaperService or a subclass of it that extends the engine?.. I’ve actually tried both – but neither seems to work. Is there something extra needed to get the tilt to work?

EDIT: Currently I’m guessing that implements SensorEventListener attached to the class that extends Engine, so the gist of my code is as follows:

EDIT: Is it related to the thread running the SensorEventListener? I read somewhere that it needs to be on the UI thread.

public class MicksWallPaper extends WallpaperService 
{
     blah blah

class MyWallPaper extends Engine implements SharedPreferences.OnSharedPreferenceChangeListener , SensorEventListener 
    {
        SensorManager sensorManager = null;
        onCreate()
        {
            sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        }

public void onSensorChanged(SensorEvent event)
        {
        Log.i("wp:","onSensorChanged");  I never see this message
            synchronized (this) 
            {
                switch (event.sensor.getType())
                {
                    case Sensor.TYPE_ORIENTATION:
                        pitch = event.values[1];
                        Log.i("pitch=",""+pitch);
                    break;
                }
            }       
        }
    }    
}

EDIT: The issue has been resolved. It’s embarrassing – I just forgot to call registerListener for my sensorManager.

(on the advice of the ogre…)

The problem is solved. It’s embarrassing – I just forgot to call registerListener for my sensorManager.