mUpdateHandler = new Handler();
    MainActivity.this.runOnUiThread(new Runnable() {
        @Override
        public void run() {
            mSeekBar.setMaxDuration(mMediaPlayer.getDuration());
            int currentPosition = mMediaPlayer.getCurrentPosition();
            mSeekBar.setCurrentPosition(mCurrentPosition);

            mUpdateHandler.postDelayed(this, 100);
        }
    });