如果我使用服务android，为什么我的应用程序关闭？

Question

I'm trying to make a simple audio player. When I create it in the main activity without service, it works correctly, music is playing (it works if I press power button to turn off the screen) and this is still working correctly after turn on the screen. But if I use service for playing music in the background, my app shuts down when I press power button for turn on the screen.

public class MainActivity extends AppCompatActivity {

    static ArrayList<HashMap<String, Object>> listSongs = new ArrayList<>();
    Intent intent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        listSongs = getAllMusicInfo();
        intent = new Intent(this, BackgroundPlayer.class);

        Button buttonStart = (Button) findViewById(R.id.startService);
        buttonStart.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startService(intent);
                Toast.makeText(MainActivity.this, "It's started", Toast.LENGTH_SHORT).show();
            }
        });

        Button buttonStop = (Button) findViewById(R.id.StopService);
        buttonStop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(intent);
                Toast.makeText(MainActivity.this, "It's stopped", Toast.LENGTH_SHORT).show();
            }
        });
    }

    public class BackgroundPlayer extends Service implements MediaPlayer.OnCompletionListener {
    MediaPlayer player;

    @Override
    public void onCreate() {
        super.onCreate();

        player = new MediaPlayer();

        try {
            player.setDataSource((String) MainActivity.listSongs.get(0).get("path"));
            player.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        player.start();
        return START_STICKY;
    }

    @Override
    public void onCompletion(MediaPlayer mp) {}
}

06-05 09:58:54.206 31873-31873/com.vitaliylevashov.serviceplayer V/MediaPlayer: start

06-05 09:58:54.206 31873-31885/com.vitaliylevashov.serviceplayer V/MediaPlayer: message received msg=6, ext1=0, ext2=0 06-05 09:58:54.206 31873-31885/com.vitaliylevashov.serviceplayer V/MediaPlayer: Received MEDIA_STARTED 06-05 09:58:54.206 31873-31885/com.vitaliylevashov.serviceplayer V/MediaPlayer: callback application 06-05 09:58:54.206 31873-31885/com.vitaliylevashov.serviceplayer V/MediaPlayer: back from callback 06-05 09:58:54.236 31873-31873/com.vitaliylevashov.serviceplayer I/MediaPlayer: Don't send intent. msg.arg1 = 0, msg.arg2 = 0 06-05 09:58:54.236 31873-31873/com.vitaliylevashov.serviceplayer E/MediaPlayer: Should have subtitle controller already set 06-05 09:58:54.256 31873-31873/com.vitaliylevashov.serviceplayer V/MediaPlayer-JNI: getCurrentPosition: 192 (msec) 06-05 09:58:54.256 31873-31873/com.vitaliylevashov.serviceplayer V/MediaPlayer-JNI: isPlaying: 1 << 06-05 09:59:25.526 31873-31873/com.vitaliylevashov.serviceplayer D/AndroidRuntime: Shutting down VM 06-05 09:59:25.526 31873-31873/com.vitaliylevashov.serviceplayer W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x41660bc0) 06-05 09:59:25.526 31873-31873/com.vitaliylevashov.serviceplayer E/AndroidRuntime: FATAL EXCEPTION: main Process: com.vitaliylevashov.serviceplayer, PID: 31873 android.database.StaleDataException: Attempted to access a cursor after it has been closed. at android.database.BulkCursorToCursorAdaptor.throwIfCursorIsClosed(BulkCursorToCursorAdaptor.java:64) at android.database.BulkCursorToCursorAdaptor.requery(BulkCursorToCursorAdaptor.java:133) at android.database.CursorWrapper.requery(CursorWrapper.java:186) at android.app.Activity.performRestart(Activity.java:5346) at android.app.ActivityThread.handleSleeping(ActivityThread.java:3487) at android.app.ActivityThread.access$3000(ActivityThread.java:155) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1428) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5433) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084) at dalvik.system.NativeStart.main(Native Method)

Answer 1

add a service tag in Manifest ,may be you havent added that in manifest

<service android:name=".MyService" />

request to post error log/logcat