java - 当应用程序进入后台时停止 MediaPlayer 服务
问题描述
我有一个媒体播放器服务,可以在我的应用程序的后台播放音乐,例如:
public class Music extends Service {
MediaPlayer player;
@Override
public IBinder onBind(Intent intent) {
return null;
}
public void onCreate() {
player = MediaPlayer.create(this, R.raw.music);
player.setLooping(true);
}
public int onStartCommand(Intent intent, int flags, int startId) {
player.start();
return Service.START_NOT_STICKY;
}
public void onDestroy() {
player.stop();
player.release();
stopSelf();
super.onDestroy();
}
问题是当用户更改应用程序或进入手机主屏幕(应用程序进入后台)时,音乐仍在播放。
我试图阻止它onStop
和onDestroy
方法,但是当我更改我不想要的活动时,这会停止音乐(我希望当用户浏览活动时音乐继续播放)。
更新
我试过广播:
我添加了
LocalBroadcastManager.getInstance(this).registerReceiver(StateReceiver, new IntentFilter("status"));
在音乐服务的 onCreate 和接收事件的方法中:
private BroadcastReceiver StateReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String status = intent.getStringExtra("status");
if (parseInt(String.valueOf(status)) == 0) {
player.stop();
}else{player.start();}
}
};
在应用程序类中,我这样做了:
public class app_class extends Application implements Application.ActivityLifecycleCallbacks {
private static int resumed;
private static int paused;
private static String currentActivity;
@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
currentActivity = activity.getClass().getSimpleName();
}
public static String getCurrentActivity() {
return currentActivity;
}
@Override
public void onActivityStarted(Activity activity) {
}
@Override
public void onActivityResumed(Activity activity) {
send_status(1);
}
@Override
public void onActivityPaused(Activity activity) {
send_status(0);
}
private void send_status(int status_counter) {
Intent intent = new Intent("status");
intent.putExtra("status", String.valueOf(status_counter));
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}
@Override
public void onActivityStopped(Activity activity) {
}
@Override
public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
}
@Override
public void onActivityDestroyed(Activity activity) {
}
但音乐不会继续
解决方案
停止播放器后,您需要再次准备播放器。如果您想在您的应用程序进入后台时停止播放,并在您的应用程序进入前台时从头开始播放媒体。只需将您的 BroadcastReceiver 代码修改为:
private BroadcastReceiver StateReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String status = intent.getStringExtra("status");
if (parseInt(String.valueOf(status)) == 0) {
player.stop();
} else {
player = MediaPlayer.create(this, R.raw.music);
player.setLooping(true);
player.start();
}
}
};
但是,如果您想暂停播放并从您离开的地方继续播放,请进行以下更改: 在您的 Application 类中,在 onActivityDestroyed() 中:
@Override
public void onActivityDestroyed(Activity activity) {
send_status(2);
}
在广播接收器中:
private BroadcastReceiver StateReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String status = intent.getStringExtra("status");
if (parseInt(String.valueOf(status)) == 0) {
player.pause(); //When app is in background and not killed, we just want to pause the player and not want to lose the current state.
} else if (parseInt(String.valueOf(status)) == 1) {
if (player != null)
player.start(); // If the player was created and wasn't stopped, it won't be null, and the playback will be resumed from where we left of.
else {
// If the player was stopped, we need to prepare it once again.
player = MediaPlayer.create(this, R.raw.music);
player.setLooping(true);
player.start();
}
} else if(player != null){
player.stop();
player.release();
}
}
};
另外,看看MediaPlayer states。
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