Sensor example not working

[phanirithvij]

I've made a sketch following the sensor example from the docs

The app crashed when used as a live wallpaper but it works when used as a regular app.

The error was

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
 at processing.test.test_android_sketch.test_android_sketch.setup(test_android_sketch.java:55)
 at processing.core.PApplet.handleDraw(PApplet.java:1838)
 at processing.opengl.PSurfaceGLES$RendererGLES.onDrawFrame(PSurfaceGLES.java:264)
 at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1553)
 at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1253)

The 55th line it mentions is

void setup(){
  ...
  manager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
  ...
}

The app works normally. But the live wallpaper doesn't.

[phanirithvij]

So context cannot be accessed when using as a live wallpaper?
I don't think that's the case as I saw many live wallpapers which use sensors to show parallax backgrounds.

What am I missing here?

[phanirithvij]

So I found the mistake.
The docs use the below method in line 26

    context = getActivity();

It should actually be

    context = getContext();

I wonder how the app even worked.