我尝试了很多方法在后台获取传感器数据，并将值存储到共享首选项或sqlite中，但都不起作用。我认为这是因为android oreo的背景限制。
我试过了
带广播接收器的报警管理器
带服务的报警管理器
现在我用的是workmanager。也不太管用。我做错什么了？现在不可能在后台获取传感器数据吗？还有别的办法吗？
主活动.java

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

    localDatabaseHelper = new LocalDatabaseHelper(getApplicationContext());
    sharedPreferences = getSharedPreferences("TEST STORAGE", MODE_PRIVATE);

    sensorManager = (SensorManager) getApplicationContext().getSystemService(Context.SENSOR_SERVICE);
    stepSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);

    WorkManager.getInstance(getApplicationContext()).cancelAllWorkByTag("Update-Shared-Preference");
    WorkRequest updateSharedPreference = new OneTimeWorkRequest.Builder(UpdateStepWork.class)
            .addTag("Update-Shared-Preference")
            .build();

    WorkManager.getInstance(getApplicationContext()).enqueue(updateSharedPreference);
}

工作

public class UpdateStepWork extends Worker implements SensorEventListener {

private SharedPreferences sharedPreferences;
private SensorManager sensorManager;
private Sensor stepSensor;
private LocalDatabaseHelper localDatabase;

public UpdateStepWork(@NonNull Context context, @NonNull WorkerParameters workerParams) {
    super(context, workerParams);
}

@NonNull
@Override
public Result doWork() {

    Log.i("WORK", "STARTED");
    sharedPreferences = getApplicationContext().getSharedPreferences("TEST STORAGE", Context.MODE_PRIVATE);
    sensorManager = (SensorManager) getApplicationContext().getSystemService(Context.SENSOR_SERVICE);
    stepSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
    localDatabase = new LocalDatabaseHelper(getApplicationContext());

    WorkManager.getInstance(getApplicationContext()).cancelAllWorkByTag("Update-Shared-Preference");
    WorkRequest updateSharedPreference = new OneTimeWorkRequest.Builder(UpdateStepWork.class)
            .setInitialDelay(5, TimeUnit.SECONDS)
            .addTag("Update-Shared-Preference")
            .build();

    WorkManager.getInstance(getApplicationContext()).enqueue(updateSharedPreference);

    sensorManager.unregisterListener(this, stepSensor);
    if(sensorManager.registerListener(this, stepSensor, SensorManager.SENSOR_DELAY_NORMAL)){
        return Worker.Result.success();
    }else
        return Worker.Result.failure();
}

@Override
public void onSensorChanged(SensorEvent event) {
    int steps = (int) event.values[0];

    Log.i("Steps from sensor", steps + "");

    if(sharedPreferences.edit().putInt("steps", steps).commit()){
        Log.i("Shared Preference", "SUCCESS STORED: " + steps);

        if(localDatabase.updateDailyData(steps)){
            Log.i("LOCAL DATABASE", "SUCCESS AT " + getCurrentTimeStamp());
            Cursor data = localDatabase.getData();

            while (data.moveToNext()) {
                Log.i("DATA", data.getString(0) + "    " + data.getInt(1));
            }
        }

    }else{
        Log.i("Shared Preference", "FAILED STORED: " + steps);
    }
    sensorManager.unregisterListener(this, stepSensor);
    sensorManager = null;
}