Android编程使用光线传感器获取光线强弱的方法【LightSensorManager封装类】

import android.content.Context;import android.hardware.Sensor;import android.hardware.SensorEvent;import android.hardware.SensorEventListener;import android.hardware.SensorManager;import android.util.Log;public class LightSensorManager {  private static final boolean DEBUG = true;  private static final String TAG = "LightSensor";  private static LightSensorManager instance;  private SensorManager mSensorManager;  private LightSensorListener mLightSensorListener;  private boolean mHasStarted = false;  private LightSensorManager() {  }  public static LightSensorManager getInstance() {    if (instance == null) {      instance = new LightSensorManager();    }    return instance;  }  public void start(Context context) {    if (mHasStarted) {      return;    }    mHasStarted = true;    mSensorManager = (SensorManager) context.getApplicationContext().getSystemService(Context.SENSOR_SERVICE);    Sensor lightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT); // 获取光线传感器    if (lightSensor != null) { // 光线传感器存在时      mLightSensorListener = new LightSensorListener();      mSensorManager.registerListener(mLightSensorListener, lightSensor, SensorManager.SENSOR_DELAY_NORMAL); // 注册事件监听    }  }  public void stop() {    if (!mHasStarted || mSensorManager == null) {      return;    }    mHasStarted = false;    mSensorManager.unregisterListener(mLightSensorListener);  }  /**   * 获取光线强度   */  public float getLux() {    if (mLightSensorListener != null) {      return mLightSensorListener.lux;    }    return -1.0f; // 默认返回-1，表示设备无光线传感器或者为调用start()方法  }  private class LightSensorListener implements SensorEventListener {    private float lux; // 光线强度    public void onAccuracyChanged(Sensor sensor, int accuracy) {    }    public void onSensorChanged(SensorEvent event) {      if (event.sensor.getType() == Sensor.TYPE_LIGHT) {        // 获取光线强度        lux = event.values[0];        if (DEBUG) {          Log.d(TAG, "lux : " + lux);        }      }    }  }}