java - 停止/启动其他 Activity 的媒体播放器

我正在尝试使用MP3作为Mediaplayer变量使用Mediaplayer播放流广播，我想在所有Fragments应用程序中播放它，希望其中一个activity（ActivityOne）包含另一个要播放的Mediaplayer MP2，所以我想在（ActivityOne）activity中停止MP1并播放MP2，并且当我从（ActivityOne）返回时想恢复MP1，我的大问题是单击button时调用的（ActivityOne）在fragment中存在
我的以下代码仅在一个方向上起作用：
当我从（ActivityOne）活动返回时，音乐停止播放。

应用程序的结构：MainAcitivty>片段> ActivityOne

MainActivity.java

MediaPlayer MP1;
boolean prepared = false;
boolean started = false;
PlayerTask playerTask;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mediaPlayer = new MediaPlayer();
    playerTask = new PlayerTask();
    playerTask.execute(stream);
    /**/
       MusicButton = findViewById(R.id.toggleButton);
    MusicButton.setVisibility(View.INVISIBLE);
    MusicButton.setOnCheckedChangeListener(new OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (started && MusicButton.isChecked()) {
                started = false;
                MP1.pause();
                MusicButton.setChecked(true);
            } else {
                started = true;
                MP1.start();
                MusicButton.setChecked(false);
            }
        }
    });
}
@SuppressLint("StaticFieldLeak")
public class PlayerTask extends AsyncTask<String, Void, Boolean> {
    ProgressBar loadingRL = findViewById(R.id.progressBar);
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
            AudioAttributes attribs = new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_MEDIA).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build();
            MP1.setAudioAttributes(attribs);

        } else {
            MP1.setAudioStreamType(AudioManager.STREAM_MUSIC);
        }
        loadingRL.setVisibility(View.VISIBLE);

    }

    @Override
    protected Boolean doInBackground(String... strings) {
        try {
            MP1.setDataSource(strings[0]);
            MP1.prepare();
            prepared = true;
        } catch (IOException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        }
        MP1.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer MP1) {
                MP1.start();

            }
        });
        return prepared;
    }

    @Override
    protected void onPostExecute(Boolean aBoolean) {
        super.onPostExecute(aBoolean);
        MusicButton.setVisibility(View.VISIBLE);
        MusicButton.setChecked(true);
         loadingRL.setVisibility(View.VISIBLE);
}

ActivityOne.java

    MediaPlayer MP2;
    boolean prepared = false;
    boolean started = false;
    ToggleButton music;
    PlayerTask playerTask = null;
    CoordinatorLayout coordinatorLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pop_for_ringtone);
        coordinatorLayout = findViewById(R.id.coord);
        MP2 = new MediaPlayer();
        playerTask = new PlayerTask();
        playerTask.execute(url);
}
  @SuppressLint("StaticFieldLeak")
    public class PlayerTask extends AsyncTask<String, Void, Boolean> {
        ProgressBar pb = findViewById(R.id.progress);

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
                AudioAttributes attribs = new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_MEDIA).setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build();
                MP2.setAudioAttributes(attribs);

            } else {
                MP2.setAudioStreamType(AudioManager.STREAM_MUSIC);
            }
        }

        @Override
        protected Boolean doInBackground(String... strings) {
            if (!isCancelled()) {
                try {
                    MP2.setDataSource(strings[0]);
                    MP2.prepare();
                    prepared = true;
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (IllegalArgumentException e) {
                    e.printStackTrace();
                } catch (IllegalStateException e) {
                    e.printStackTrace();
                }
                MP2.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
                    @Override
                    public void onPrepared(MediaPlayer MP2) {
                        MP2.start();
                    }
                });

            }
            return prepared;
        }

        @Override
        protected void onPostExecute(Boolean aBoolean) {
            super.onPostExecute(aBoolean);
            music.setEnabled(true);
            music.setVisibility(View.VISIBLE);
            music.setChecked(true);
            all.setVisibility(View.VISIBLE);
        }

        @Override
        protected void onCancelled(Boolean aBoolean) {
            if (isCancelled() && MP2.isPlaying()) {
                MP2.stop();
            }
        }
    }

 @Override
    public void onBackPressed() {
        if (playerTask != null && playerTask.getStatus() == AsyncTask.Status.FINISHED) {
            if (MP2.isPlaying()) {
                MP2.stop();
            }
        } else if (playerTask != null && playerTask.getStatus() != AsyncTask.Status.FINISHED) {
            playerTask.cancel(true);
        }
        super.onBackPressed();
    }

我花了2天的时间解决此问题，但没有任何结果，请有人帮助我，我将感谢他

最佳答案

您可以使用Otto库解决此问题。首先创建一个新的Java类，但选择enum，然后在enum中可以添加：PLAY和PAUSE例如：

public enum PlaybackEvent {
   PLAY, PAUSE
}

然后，如果您不使用自定义Application类，请创建一个类并在Application方法内扩展override和onCreate。在您的app gradle中添加compile 'com.squareup:otto:1.3.8'，然后在Bus类内创建Application的实例并注册。例如，这看起来像这样：

public class MApplication extends Application {
public static Bus sBus = new Bus(ThreadEnforcer.MAIN);
@Override
public void onCreate() {
    super.onCreate();
    sBus.register(this);
}

不要忘记用您的新应用替换清单默认应用程序类

<application android:name="com.packagename.MApplication"

之后，在MainActivity类override中，并在onResume和onPause中注册/注销事件总线。

 @Override
protected void onResume() {
    super.onResume();
    try {
      MApplication.sBus.register(this);
    }
   catch(Exception e){
      e.printStackTrace();
   }
}

@Override
protected void onDestroy() {
    super.onDestroy();
   try {
      MApplication.sBus.unregister(this);
    }
   catch(Exception e){
      e.printStackTrace();
   }
}

之后，在MainActivity中创建一个作为参数public void和PlayBackEvent传递的Subscribe方法，以便您可以侦听将从fragment类发送的消息。例如：

 @Subscribe
public void handlePlaybackEvent(PlaybackEvent event) {
    switch (event) {
        case PLAY:
           if(MP1.isPlaying())
             MP1.pause();
            break;
        case PAUSE:
            if(!MP1.isPlaying())
             MP1.play();
            break;
    }
}

最后要做的就是在开始第二个活动时从fragment发送消息，然后该消息就会发送：

 MApplication.sBus.post(PlaybackEvent.PAUSE);

当然，您也可以发送一条消息，从第二个活动overriding onBackPressed的另一行代码中再次播放MP1：

 MApplication.sBus.post(PlaybackEvent.PLAY);

希望这可以帮助您解决问题。