wallpaperOffset() not updating

this is my Current Code:

void setup() {
  fullScreen();
}
void draw() {
  background(33);
  text(wallpaperHomeCount()+" "+wallpaperOffset()+" "+random(1),width/2,height/2);
}

I can't get it to output anything else than "1 0.5 random" did i understand something wrong? (i used the random number to prove that the frame is updating)

http://android.processing.org/reference/wallpapers/offset.html (Android Mode 4.0 & Android 4.4.3)