How to save an AnimationDrawable as a GIF?

Question

i want to create a gif, i have created a animation using AnimationDrawable as shown below.

for (Bitmap bitmap: bitmaps) {
    animation.addFrame(new BitmapDrawable(getResources(), bitmap), duration);
}
animation.setOneShot(false);
mImageView.setImageDrawable(animation);

Now i want to save this as gif. how am i supposed to do it?

i tried using these two libraries:
https://github.com/nbadal/android-gif-encoder,
https://gist.github.com/wasabeef/8785346

they are both same, when i save it only one, first image is shown. Can anyone help. Thanks!