java - MediaPlayer 中的 IllegalStateException#Pause

Question

我在谷歌控制台和预启动报告中上传了我的应用程序，仅在 2 台设备上出现了这个问题 java.lang.IllegalStateException

FATAL EXCEPTION: ControllerMessenger
Process: com.wolframite.manos.crack_the_code, PID: 11744
java.lang.IllegalStateException
at android.media.MediaPlayer.isPlaying(Native Method)
at com.wolframite.manos.crack_the_code.Music$1.onReceive(Music.java:36)
at android.support.v4.content.LocalBroadcastManager.executePendingBroadcasts(LocalBroadcastManager.java:311)
at android.support.v4.content.LocalBroadcastManager.access$000(LocalBroadcastManager.java:47)
at android.support.v4.content.LocalBroadcastManager$1.handleMessage(LocalBroadcastManager.java:120)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.support.test.espresso.base.Interrogator.a(Interrogator.java:19)
at android.support.test.espresso.base.UiControllerImpl.a(UiControllerImpl.java:142)
at android.support.test.espresso.base.UiControllerImpl.a(UiControllerImpl.java:134)
at android.support.test.espresso.base.UiControllerImpl.a(UiControllerImpl.java:34)
at android.support.test.espresso.action.MotionEvents.a(MotionEvents.java:74)
at android.support.test.espresso.action.MotionEvents.a(MotionEvents.java:52)
at android.support.test.espresso.action.Tap.c(Tap.java:9)
at android.support.test.espresso.action.Tap.a(Tap.java:19)
at android.support.test.espresso.action.Tap$1.b(Tap.java:2)
at android.support.test.espresso.action.GeneralClickAction.perform(GeneralClickAction.java:22)
at android.support.test.espresso.ViewInteraction$SingleExecutionViewAction.perform(ViewInteraction.java:9)
at android.support.test.espresso.ViewInteraction.a(ViewInteraction.java:78)
at android.support.test.espresso.ViewInteraction.a(ViewInteraction.java:94)
at android.support.test.espresso.ViewInteraction$1.call(ViewInteraction.java:3)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.Handler.handleCallback(Handler.java:746)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5459)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:728)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

我不知道该怎么办。 这是什么问题，我还需要上传什么来帮助解决这个问题。

用于在应用程序中播放音乐并在应用程序进入后台停止音乐以及应用程序进入前台恢复音乐时接收广播的音乐类，第 36 行是 player.pause() :

public class Music extends Service {
private MediaPlayer player;

@Override
public IBinder onBind(Intent intent) {
    return null;
}
public void onCreate() {
    player = MediaPlayer.create(this, R.raw.music);
    player.setLooping(true);
    LocalBroadcastManager.getInstance(this).registerReceiver(StateReceiver, new IntentFilter("status"));

}
private final 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();
        } else if (parseInt(String.valueOf(status)) == 1) {
            if (player != null)
                player.start();
            else {
                player = MediaPlayer.create(Music.this, R.raw.music);
                player.setLooping(true);
                player.start();
            }
        } else if(player != null){
            player.stop();
            player.release();
        }

    }
};
public int onStartCommand(Intent intent, int flags, int startId) {
    player.start();
    return Service.START_NOT_STICKY;
}
public void onDestroy() {
    player.stop();
    player.release();
    LocalBroadcastManager.getInstance(this).unregisterReceiver(StateReceiver);
    stopSelf();
    super.onDestroy();

}

Answer 1

为了避免这些类型的错误，您可以创建一个实用程序类作为 MediaPlayer 方法的安全包装器，这些方法有时会引发意外异常并使您的应用程序崩溃。

我在一个名为 MediaPlayerUtils 的类中使用代码来避免这些类型的行为并为我的应用程序添加额外的安全层:

public static void pause(MediaPlayer mediaPlayer) {
    if (mediaPlayer != null) {
        try {
            if (mediaPlayer.isPlaying()) {
                mediaPlayer.pause();
            }
        } catch (Exception e) {
            Log.w(MediaPlayerUtil.class.getName(),
                    String.format("Failed to stop media player: %s", e));
        }
    }
}

然后你必须使用而不是:

player.pause(); // not safe

这段代码:

MediaPlayerUtils.pause(player);  // safe

您可以为 MediaPlayer.stop() 添加类似的方法，例如:;

public static void stop(MediaPlayer mediaPlayer) {
    if (mediaPlayer != null) {
        try {
            if (mediaPlayer.isPlaying()) {
                mediaPlayer.stop();
            }
            resetRelease(mediaPlayer);
        } catch (Exception e) {
            Log.e(MediaPlayerUtil.class.getName(),
                    String.format("Failed to stop media player: %s", e));
        }
    }
}