android - per pixel based collision detection

I was wondering if anyone had any ideas on how to get per pixel collision detection for the android. I saw that the andEngine has great collision detection on rotation as well but couldn't see where the actual detection happened per pixel. Also noticed a couple solutions for java, could these be replicated for use with the Android SDK?

Maybe someone here has a clean piece of code I could look at to help understand what is going on with per pixel detection and also why when rotating it is a different process.

EDIT: Here is something I am working with right now.

public void getBitmapData(Bitmap bitmap1, Bitmap bitmap2){
     int[] bitmap1Pixels;
     int[] bitmap2Pixels;


    int bitmap1Height = bitmap1.getHeight();
    int bitmap1Width = bitmap1.getWidth();
    int bitmap2Height = bitmap2.getHeight();
    int bitmap2Width = bitmap2.getWidth();
    bitmap1Pixels = new int[bitmap1Height * bitmap1Width];
    bitmap2Pixels = new int[bitmap2Height * bitmap2Width];

    bitmap1.getPixels(bitmap1Pixels, 0, bitmap1Width, 1, 1, bitmap1Width - 1, bitmap1Height - 1); 
    bitmap2.getPixels(bitmap2Pixels, 0, bitmap2Width, 1, 1, bitmap2Width - 1, bitmap2Height - 1); 

}