如何让音乐停止?

Question

所以我做了一个媒体播放器，工作得很好，但我有一个大问题，按下播放后，如果我关闭活动或应用程序，音乐继续播放，如果我再次点击，音乐播放在另一个，我不知道如何解决它。我只是希望音乐在关闭活动或应用程序后没有任何问题地停止。

下面是完整的代码:

public class m1 extends AppCompatActivity {
ImageView backm1, replay, forward, btPlay, btPause;
TextView playerPosition, playerDuration;
CircularSeekBar seekBar;
MediaPlayer mediaPlayer;
Handler handler = new Handler();
Runnable runnable;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_m1);
backm1 = (ImageView) findViewById(R.id.backm1);
backm1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
m1.super.onBackPressed();
}
});
playerPosition = findViewById(R.id.playerPosition);
playerDuration = findViewById(R.id.playerDuration);
replay = findViewById(R.id.replay);
forward = findViewById(R.id.forward);
seekBar = findViewById(R.id.seekBar);
btPause = findViewById(R.id.btPause);
btPlay = findViewById(R.id.btPlay);
mediaPlayer = MediaPlayer.create(this,R.raw.ding_dong);
runnable = new Runnable() {
@Override
public void run() {
seekBar.setProgress(mediaPlayer.getCurrentPosition());
handler.postDelayed(this,500);
}
};
int duration = mediaPlayer.getDuration();
String sDuration = convertFormat(duration);
playerDuration.setText(sDuration);
btPlay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
btPlay.setVisibility(View.GONE);
btPause.setVisibility(View.VISIBLE);
mediaPlayer.start();
seekBar.setMax(mediaPlayer.getDuration());
handler.postDelayed(runnable, 0);
}
});
btPause.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
btPause.setVisibility(View.GONE);
btPlay.setVisibility(View.VISIBLE);
mediaPlayer.pause();
handler.removeCallbacks(runnable);
}
});
forward.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int currentPosition = mediaPlayer.getCurrentPosition();
int duration = mediaPlayer.getDuration();
if(mediaPlayer.isPlaying() && duration != currentPosition){
currentPosition = currentPosition + 10000;
playerPosition.setText(convertFormat(currentPosition));
mediaPlayer.seekTo(currentPosition);
}
}
});
replay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int currentPosition = mediaPlayer.getCurrentPosition();
if (mediaPlayer.isPlaying() && currentPosition > 10000){
currentPosition = currentPosition - 10000;
playerPosition.setText(convertFormat(currentPosition));
mediaPlayer.seekTo(currentPosition);
}
}
});
seekBar.setOnSeekBarChangeListener(new CircularSeekBar.OnCircularSeekBarChangeListener() {
@Override
public void onProgressChanged(CircularSeekBar circularSeekBar, float v, boolean b) {
if (b) {
mediaPlayer.seekTo((int) v);
}
playerPosition.setText(convertFormat(mediaPlayer.getCurrentPosition()));
}
@Override
public void onStopTrackingTouch(CircularSeekBar circularSeekBar) {
}
@Override
public void onStartTrackingTouch(CircularSeekBar circularSeekBar) {
}
});
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
btPause.setVisibility((View.GONE));
btPlay.setVisibility(View.VISIBLE);
mediaPlayer.seekTo(0);
}
});
}

@SuppressLint("DefaultLocale")
private String convertFormat(int duration) {
return String.format("%02d:%02d"
,TimeUnit.MILLISECONDS.toMinutes(duration)
,TimeUnit.MILLISECONDS.toSeconds(duration) -
TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(duration)));
}
@Override
protected void onDestroy() {
super.onDestroy();
if(mediaPlayer !=null){
mediaPlayer.stop();
mediaPlayer.release();
}
}
}

我添加了onDestroy，但是我认为用了错误的方式，出现了这个错误:

2021-03-08 10:13:40.843 419-4716/? E/AudioSystem: invalid attributes { Content type: AUDIO_CONTENT_TYPE_UNKNOWN Usage: AUDIO_USAGE_UNKNOWN Source: -1 Flags: 0x800 Tags:  } when converting to stream
2021-03-08 10:13:40.906 28868-28868/com.example.diligent E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.diligent, PID: 28868
java.lang.IllegalStateException
at android.media.MediaPlayer.getCurrentPosition(Native Method)

我添加了这个:

private void stopPlayer() {
if (mediaPlayer != null) {
mediaPlayer.release();
mediaPlayer = null;
Toast.makeText(this, "MediaPlayer released", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onStop() {
super.onStop();
stopPlayer();
}

和以下错误:

java.lang.NullPointerException: Attempt to invoke virtual method 'int android.media.MediaPlayer.getCurrentPosition()' on a null object reference

欢迎提出其他建议。

提前谢谢你。

Answer 1

停止并释放活动onDestroy上的媒体资源。

@Override
protected void onDestroy() {
super.onDestroy();
if(mediaPlayer !=null){
mediaPlayer.stop();
mediaPlayer.release();
}
}

Answer 2

MediaPlayer player; //MediaPlayer object 

*停止媒体播放*

private void stopPlayer() {
if (player != null) {
player.release();
player = null;
Toast.makeText(this, "MediaPlayer released", Toast.LENGTH_SHORT).show();
}
}

调用onStop()回调函数

@Override
protected void onStop() {
super.onStop();
stopPlayer();
}