Android RatingBar: getProgressDrawable doesn't cast to right Class

I am using

This line of code

    LayerDrawable stars = (LayerDrawable) rating_bar.getProgressDrawable();

works fine on my Nexus 4 emulator API v21. When trying the same code on my Galaxy S4 API v19, I get the following error message:

 Caused by: java.lang.ClassCastException: android.support.v7.internal.widget.TintDrawableWrapper cannot be cast to android.graphics.drawable.LayerDrawable

What is happening?

I am building with the latest build tools 22, my target API is 22 is as well.

Solution

What happens is clearly explained in the error message :

TintDrawableWrapper cannot be cast to android.graphics.drawable.LayerDrawable

The support lib creates a wrapper in order to handle retro compatibility, you just need to take it into account. Have a look at the lib implementation, it probably wraps around a LayerDrawable.

You will need to do something along the lines of :

LayerDrawable stars = getProgressDrawable(rating_bar);
}

private LayerDrawable getProgressDrawable(RatingBar ratingBar) {
  if (Build.VERSION >= LOLLIPOP) {
    return (LayerDrawable) ratingBar.getProgressDrawable();
  } else {
    // fetch the LayerDrawable based on Google's support implementation,  
    // probably a simple findViewById()
  }
}