mHandler = new Handler(getMainLooper());
        mHandler.post(mDotAnimRunable);



private Runnable mDotAnimRunable = new Runnable() {
        private String dotStr="";
        @Override
        public void run() {
            mDot_tv.setText(dotStr);
            mHandler.postDelayed(this, 500);
            dotStr= dotStr.length()==0 ? "." : dotStr.length()==1 ? ".." : dotStr.length()==2 ? "..." : "";
        }
    };



@Override
    protected void onDestroy() {
        super.onDestroy();
      
        mHandler.removeCallbacks(mDotAnimRunable);
    }