Question

I’m trying to generate a random animation to load for an ImageView. It works, but only sometimes. After three animations are picked, it will throw an ArrayIndexOutOfBoundsException and I’m not sure why. If I catch the Exception, three animations will be picked at random, then none will load.

final int[] anim = { R.anim.anim_0, R.anim.anim_1, R.anim.anim_2,
            R.anim.anim_3, R.anim.anim_4, R.anim.anim_5 }; 

Random ran = new Random();

int i = ran.nextInt(6 - 1);

mAlbum.startAnimation(AnimationUtils.loadAnimation(
                        getBaseContext(), anim[i++]));

Answer 1

Try anim[ran.nextInt(anim.length)] instead. This will choose a number from zero (inclusive) to the number of elements in the array (exclusive) and will prevent the exception.

int i = ran.nextInt(anim.length);
mAlbum.startAnimation(AnimationUtils.loadAnimation(
                    getBaseContext(), anim[i]));