如果我使用服务 android，为什么我的应用程序会关闭？

Question

我正在尝试制作一个简单的音频播放器。当我在没有服务的主要活动中创建它时，它可以正常工作，正在播放音乐（如果我按电源按钮关闭屏幕，它会工作）并且在打开屏幕后仍然可以正常工作。但是如果我使用服务在后台播放音乐，当我按下电源按钮打开屏幕时，我的应用程序会关闭。

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: 收到消息 msg=6, ext1=0, ext2=0 06-05 09:58:54.206 31873-31885/com.vitaliylevashov.serviceplayer V/MediaPlayer：收到 MEDIA_STARTED 06-05 09:58:54.206 31873-31885/com.vitaliylevashov.serviceplayer V/MediaPlayer：回调应用 06-05 09:58:54.206 31873-31885/com.vitaliylevashov.serviceplayer V/MediaPlayer：从回调中返回 06-05 09:58:54.236 31873-31873/com.vitaliylevashov.serviceplayer I/MediaPlayer：不要发送意图。 msg.arg1 = 0, msg.arg2 = 0 06-05 09:58:54.236 31873-31873/com.vitaliylevashov.serviceplayer E/MediaPlayer：应该已经设置了字幕控制器 06-05 09:58:54.256 31873-31873/com.vitaliylevashov.serviceplayer V/MediaPlayer-JNI：getCurrentPosition：192（毫秒） 06-05 09:58:54.256 31873-31873/com.vitaliylevashov.serviceplayer V/MediaPlayer-JNI: isPlaying: 1

Answer 1

在 Manifest 中添加一个服务标签，可能你还没有在 manifest 中添加它

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

请求发布错误日志/logcat