java - onSensorChanged 在锁定屏幕 3 分钟后停止调用

Question

我正在尝试开发一个简单的应用程序，它将在 txt 或 csv 文件中记录用户的 Activity (加速度计值)。

我的应用程序由 2 个 Java 类 MainActivity 和 MyService 组成。 MainActivity 包含两个用于启动和停止服务的按钮以及所需的权限。但是，onSensorChanged 通常会在锁定手机(关闭屏幕)后的前 3 分钟内记录，然后停止记录。一旦我打开屏幕，logd 就会再次开始工作。 txt 文件中的记录具有相同的行为。我发现如果我覆盖电池优化，该应用程序似乎运行良好。但是，我需要手机也以打瞌睡模式工作，以节省电池电量。还有其他人遇到过类似的问题吗？

这是我的前台服务:

public class MyService extends Service implements SensorEventListener {

    public static final String CHANNEL_ID = "ForegroundServiceChannel";
    private static final String TAG = "MyService";

    private Messenger messageHandler;


    private SensorManager mSensorManager;
    private Sensor mAccelerometer;
    private Context mContext;
    private PowerManager.WakeLock wakeLock = null;

    //private HandlerThread mSensorThread;
    //private Handler mHandler;

    @SuppressLint("MissingPermission")
    @Override
    public void onCreate() {
        super.onCreate();
        Log.v("shake service startup", "registering for shake");
        mContext = getApplicationContext();

        //mHandler = new Handler(mSensorThread.getLooper());

        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mAccelerometer = mSensorManager
                .getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mSensorManager.registerListener(this, mAccelerometer,
                SensorManager.SENSOR_DELAY_NORMAL);


        PowerManager manager = (PowerManager) getSystemService(Context.POWER_SERVICE);
        wakeLock = manager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Wakelock :: TAG");

        // Register our receiver for the ACTION_SCREEN_OFF action. This will make our receiver
        // code be called whenever the phone enters standby mode.
        //IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_OFF);
        //registerReceiver(mReceiver, filter);
    }


    /*
    // BroadcastReceiver for handling ACTION_SCREEN_OFF.
    public BroadcastReceiver mReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            // Check action just to be on the safe side.
            if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
                Log.v("shake mediator screen off","trying re-registration");
                // Unregisters the listener and registers it again.
                mSensorManager.unregisterListener(MyService.this);
                mSensorManager.registerListener(MyService.this, mAccelerometer,
                        SensorManager.SENSOR_DELAY_NORMAL, mHandler);
            }
        }
    };
    */

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        String input = intent.getStringExtra("inputExtra");
        createNotificationChannel();
        Intent notificationIntent = new Intent(this, MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(this,
                0, notificationIntent, 0);

        Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
                .setContentTitle("Foreground Service")
                .setContentText(input)
                .setSmallIcon(R.drawable.ic_launcher)
                .setContentIntent(pendingIntent)
                .build();

        startForeground(1, notification);

        return START_STICKY;

        //stopSelf();

        //return START_NOT_STICKY;
    }

    private void createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel serviceChannel = new NotificationChannel(
                    CHANNEL_ID,
                    "Foreground Service Channel",
                    NotificationManager.IMPORTANCE_DEFAULT
            );

            NotificationManager manager = getSystemService(NotificationManager.class);
            manager.createNotificationChannel(serviceChannel);
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if(mSensorManager != null){
            //noinspection MissingPermission
            mSensorManager.unregisterListener(MyService.this);
        }
        //unregisterReceiver(mReceiver);
        try{
            wakeLock.release();//always release before acquiring for safety just in case
        }
        catch(Exception e){
            //probably already released
            Log.e(TAG, e.getMessage());
        }

    }

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



    @Override
    public void onSensorChanged(SensorEvent event) {
        Log.d(TAG, "onSensorChanged: " + event.timestamp + " " + event.values[0] + " " + event.values[1] + " " + event.values[2]);
        recordAccelValues(String.valueOf(event.timestamp),  event.values[0] + " " + event.values[1] + " " + event.values[2]);
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }

    private void recordAccelValues(String time, String accel_values) {
        String record = time + " " + accel_values  + "\n";

        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            if (Build.VERSION.SDK_INT >= 23) {
                File sdcard = Environment.getExternalStorageDirectory();
                File dir = new File(sdcard.getAbsolutePath() + "/text/");
                if(!dir.exists()) {
                    dir.mkdir();
                }
                File file = new File(dir, "dailyRecordsAccel.dat");
                FileOutputStream os = null;
                try {
                    os = new FileOutputStream(file, true);
                    os.write(record.getBytes());
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
        }

    }


}

正如您在代码中看到的，我尝试了我发现的其他问题中的一些建议，例如唤醒锁和Intent.ACTION_SCREEN_OFF，但它们似乎不起作用。 Accelerometer stops delivering samples when the screen is off on Droid/Nexus One even with a WakeLock

Answer 1

保持服务活跃的唯一方法是避免应用程序的电池优化。这可以通过以下两种方式实现。 请注意!在这两种情况下，您都会使设备保持 Activity 状态，这意味着设备永远不会 hibernate (显然会进入打瞌睡状态)。这是设备 sleep 的全部目的，以避免像您这样的后台服务的待处理工作。

• 使用 Android WakeLock，例如。以下。

   val wakeLock: PowerManager.WakeLock =
           (getSystemService(Context.POWER_SERVICE) as PowerManager).run {
               newWakeLock(PowerManager. FULL_WAKE_LOCK, "MyApp::MyWakelockTag").apply {
                acquire()
            }
        }

• 更改设置以避免针对特定应用进行电池优化。正如您在问题中提到的。