<uses-permission android:name="android.permission.DEVICE_POWER"/><uses-permission android:name="android.permission.WAKE_LOCK"/>

public class MainActivity extends Activity implements SensorEventListener {    public static final String TAG = "SensorTest";    //调用距离传感器，控制屏幕    private SensorManager mManager;//传感器管理对象    //屏幕开关    private PowerManager localPowerManager = null;//电源管理对象    private PowerManager.WakeLock localWakeLock = null;//电源锁    //TextView    private TextView tv;//基本上没啥用    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                tv = (TextView) findViewById(R.id.tv);        mManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);        //获取系统服务POWER_SERVICE，返回一个PowerManager对象        localPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);        //获取PowerManager.WakeLock对象,后面的参数|表示同时传入两个值,最后的是LogCat里用的Tag         localWakeLock = this.localPowerManager.newWakeLock(32, "MyPower");//第一个参数为电源锁级别，第二个是日志tag    }    public void onResume(){        super.onResume();        mManager.registerListener(this, mManager.getDefaultSensor(Sensor.TYPE_PROXIMITY),// 距离感应器                SensorManager.SENSOR_DELAY_NORMAL);//注册传感器，第一个参数为距离监听器，第二个是传感器类型，第三个是延迟类型    }    public void onStop(){        super.onStop();        Log.d(TAG,"on stop");    }    public void onDestroy(){        super.onDestroy();        Log.d(TAG,"on destroy");        if(mManager != null){            localWakeLock.release();//释放电源锁，如果不释放finish这个acitivity后仍然会有自动锁屏的效果，不信可以试一试            mManager.unregisterListener(this);//注销传感器监听        }    }    @Override    public void onSensorChanged(SensorEvent event) {        float[] its = event.values;        //Log.d(TAG,"its array:"+its+"sensor type :"+event.sensor.getType()+" proximity type:"+Sensor.TYPE_PROXIMITY);        if (its != null && event.sensor.getType() == Sensor.TYPE_PROXIMITY) {            System.out.println("its[0]:" + its[0]);            tv.setText(its[0]+"");            //经过测试，当手贴近距离感应器的时候its[0]返回值为0.0，当手离开时返回1.0            if (its[0] == 0.0) {// 贴近手机                System.out.println("hands up");                Log.d(TAG,"hands up in calling activity");                if (localWakeLock.isHeld()) {                    return;                } else{                    localWakeLock.acquire();// 申请设备电源锁                }            } else {// 远离手机                System.out.println("hands moved");                Log.d(TAG,"hands moved in calling activity");                if (localWakeLock.isHeld()) {                    return;                } else{                    localWakeLock.setReferenceCounted(false);                    localWakeLock.release(); // 释放设备电源锁                }            }        }    }    @Override    public void onAccuracyChanged(Sensor sensor, int accuracy) {        // TODO 自动生成的方法存根    }}