android - 如何取消监听器每 5 秒读取一次事件

Question

我正在尝试每 5 秒向服务器发送一次磁场传感器的数据，但我遇到了从读取数据中注销 sensorListerner 的问题。我试过这样 sensorManager.registerListener(this,
sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),1000 * 10); 也是，但没有 seccuss。目前数据在一秒钟内被发送到服务器 12 次。

感谢任何帮助。

代码:

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

您提供的速率 1000 * 10 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() 方法取消注册您的监听器。