如何取消侦听器以每 5 秒读取一次事件

Question

我正在尝试每 5 秒将磁场传感器的数据发送到服务器，但我遇到了取消注册传感器读取数据的问题。我也sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),1000 * 10);这样尝试过，但没有秒杀。目前，数据在一秒钟内发送到服务器 12 次。

我感谢任何帮助。

法典：

public class MainActivity extends ActionBarActivity implements
        SensorEventListener {
    String telsaString;
    private TextView magneticX;
    private TextView magneticY;
    private TextView magneticZ;
    private TextView magneticT;
    private SensorManager sensorManager = null;
    private float magX;
    private float magY;
    private float magZ;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        // Capture magnetic sensor related view elements
        magneticX = (TextView) findViewById(R.id.valMag_X);
        magneticY = (TextView) findViewById(R.id.valMag_Y);
        magneticZ = (TextView) findViewById(R.id.valMag_Z);
        magneticT = (TextView) findViewById(R.id.valMag_T);
        // Register magnetic sensor
         sensorManager.registerListener(this,
         sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
         SensorManager.SENSOR_DELAY_NORMAL);

           final SensorEventListener listener = this;
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    sensorManager.unregisterListener(listener);
                }
            }, 5000);
    }
    @Override
    protected void onPause() {
        // Unregister the listener
        sensorManager.unregisterListener(this);
        super.onPause();
    }
    @Override
    protected void onStop() {
        // Unregister the listener
        sensorManager.unregisterListener(this);
        super.onStop();
    }
    @Override
    protected void onResume() {
        super.onResume();
        sensorManager.registerListener(this,
                sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
                SensorManager.SENSOR_DELAY_NORMAL);
    }
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
    public void onSensorChanged(SensorEvent sensorEvent) {
        synchronized (this) {
            if (sensorEvent.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {

                magX = sensorEvent.values[0];
                magY = sensorEvent.values[1];
                magZ = sensorEvent.values[2];
                magneticX.setText(Float.toString(sensorEvent.values[0]));
                magneticY.setText(Float.toString(sensorEvent.values[1]));
                magneticZ.setText(Float.toString(sensorEvent.values[2]));
                double teslaXYZ = (Math.sqrt((magX * magX) + (magY * magY)
                        + (magZ * magZ)));
                magneticT.setText(Double.toString(teslaXYZ));
                try {
                    JSONObject tesla = new JSONObject();
                    tesla.put("tesla", teslaXYZ);
                    telsaString = tesla.toString();
                    new MyAsyncTask().execute(telsaString);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }
    }

编辑：

        sensorManager.registerListener(this,
                sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
                10*1000*1000);
.
.
.
.
            long curTime = System.currentTimeMillis();
            if ((curTime - lastUpdate) > 10000) {
                lastUpdate = curTime;
           }

Answer 1

您1000 * 10提供的速率以微秒为单位，因此您请求的更新周期为 10 毫秒。请注意，请求的采样周期只是一个请求。速率可能更快或更慢，您需要跟踪时间并做适当的事情。当您希望完全停止接收事件时，请使用 SensorManager.unregisterListener() 方法取消注册侦听器。