关于android方向传感器的使用

package com.turtle920.androidaudioprocess;

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

//实现传感器事件监听：SensorEventListener
public class MainActivity extends Activity implements SensorEventListener{

    private SensorManager sensorManager;
    private Sensor acc_sensor;
    private Sensor mag_sensor;
    //加速度传感器数据
    float accValues[]=new float[3];
    //地磁传感器数据
    float magValues[]=new float[3];
    //旋转矩阵，用来保存磁场和加速度的数据
    float r[]=new float[9];
    //模拟方向传感器的数据（原始数据为弧度）
    float values[]=new float[3];
    int counter=0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        acc_sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mag_sensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
        //给传感器注册监听：
        sensorManager.registerListener(this, acc_sensor, SensorManager.SENSOR_DELAY_NORMAL);
        sensorManager.registerListener(this, mag_sensor, SensorManager.SENSOR_DELAY_NORMAL);
    }

    //传感器状态改变时的回调方法
    @Override
    public void onSensorChanged(SensorEvent event) {
        if(event.sensor.getType()==Sensor.TYPE_ACCELEROMETER){
            accValues=event.values;
        }
        else if(event.sensor.getType()==Sensor.TYPE_MAGNETIC_FIELD){
            magValues=event.values;
        }
        /**public static boolean getRotationMatrix (float[] R, float[] I, float[] gravity, float[] geomagnetic)
         * 填充旋转数组r
         * r：要填充的旋转数组
         * I:将磁场数据转换进实际的重力坐标中 一般默认情况下可以设置为null
         * gravity:加速度传感器数据
         * geomagnetic：地磁传感器数据
         */
        SensorManager.getRotationMatrix(r, null, accValues, magValues);
        /**
         * public static float[] getOrientation (float[] R, float[] values)
         * R：旋转数组
         * values ：模拟方向传感器的数据
         */

        SensorManager.getOrientation(r, values);

        if (counter++ % 10==1){
            Log.e("DEBUG", "x:"+Math.toDegrees(values[0])+" y:"+Math.toDegrees(values[1])+" z:"+Math.toDegrees(values[2]));
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }

}