Android 接近传感器实现判断接听电话

package com.example.androidapp;

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {

private SensorManager mSensorManager=null;
private Sensor mSensor=null;
private TextView textView1=null;
private Button button1=null;
private Button button2=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView1=(TextView)findViewById(R.id.textView1);
/*获取系统服务（SENSOR_SERVICE）返回一个SensorManager对象*/
mSensorManager=(SensorManager)getSystemService(SENSOR_SERVICE);
/*通过SensorManager获取相应的（接近传感器）Sensor类型对象*/
mSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
/*注册相应的SensorService*/
button1=(Button)findViewById(R.id.button1);
button1.setOnClickListener(new Button.OnClickListener() {

@Override
public void onClick(View arg0) {
mSensorManager.registerListener(mSensorEventListener, mSensor
, SensorManager.SENSOR_DELAY_NORMAL);
}
});
/* 销毁相应的SensorService
* 很关键的部分，注意，说明文档中提到，即使Activity不可见的时候，感应器依然会继续工作
* 所以一定要关闭触发器，否则将消耗用户大量电量*/
button2=(Button)findViewById(R.id.button2);
button2.setOnClickListener(new Button.OnClickListener() {

@Override
public void onClick(View v) {
mSensorManager.unregisterListener(mSensorEventListener, mSensor);
}
});
}
/*声明一个SensorEventListener对象用于侦听Sensor事件，并重载onSensorChanged方法*/
private final SensorEventListener mSensorEventListener=new SensorEventListener() {

@Override
public void onSensorChanged(SensorEvent event) {
if(event.sensor.getType()==Sensor.TYPE_PROXIMITY){
/*接近传感器检测物体与听筒的距离，单位是厘米。*/
float distance=event.values[0];
textView1.setText(String.valueOf(distance)+"cm");
}
}

@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub

}
};

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}