gistfile1.txt

 public void PlayAudio() {

        if (mediaPlayer == null) {
            mediaPlayer = new MediaPlayer();
        }
        if (!TextUtils.isEmpty(mediaFileUrl)) {
            try {
                mediaPlayer.reset();
                mediaPlayer.setDataSource(mediaFileUrl);
                mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                mediaPlayer.prepare();
                startAudio();  // when calling startAudio from here its playing audio but when calling startAudio from button press then its not playing
              
            } catch (IllegalArgumentException e) {
                e.printStackTrace();
            } catch (IllegalStateException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            Log.e(DetailActivityAudio.class.getName(), "mediaFileUrl:" + mediaFileUrl);
        }
    }

    private void startAudio() {
        mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            public void onPrepared(MediaPlayer mp) {
                if(!mediaPlayer.isPlaying())
                {
                    mediaPlayer.start();
                    mediaPlayer.seekTo(audioLength);
                }
            }
        });
    }