android textview 設置 上下左右drawable

Drawable drawable = getResources().getDrawable(R.drawable.icon_public);
//一定要加這行！！！！！！！！！！！
                drawable.setBounds(0, 0, drawable.getMinimumWidth(), drawable.getMinimumHeight());
                tv_public.setCompoundDrawables(null,drawable,null,null);