this is a simple code for setting a custom drawable for back button placed on toolbar
if (SharedPreferenceHelper.getDefaultLanguage(getActivity()).equals(SharedPreferenceHelper.ARABIC_LOCAL_LANGUAGE)) {
((AppCompatActivity) getActivity()).getSupportActionBar().setHomeAsUpIndicator(R.drawable.ar_back);
}
else {
((AppCompatActivity) getActivity()).getSupportActionBar().setHomeAsUpIndicator(R.drawable.back);
}