安卓百度地图开发（三）在定位图层获取指南针角度

在官方文档中没有给出获取角度的方法，这里使用了安卓自带的传感器获取指南针角度

首先定义传感器和角度：

private SensorManager mSensorManager; 

double degree = 0;

在oncreate方法中初始化传感器

//指南针
        mSensorManager= (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        Sensor magenticSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
        Sensor accelerometerSensor=mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mSensorManager.registerListener(listener,magenticSensor,SensorManager.SENSOR_DELAY_GAME);
        mSensorManager.registerListener(listener,accelerometerSensor,SensorManager.SENSOR_DELAY_GAME); 

定义listener

    //指南针 获取degree值
    private SensorEventListener listener=new SensorEventListener() {
        float[] accelerometerValues=new float[3];
        float[] magenticValues=new float[3];
        @Override
        public void onSensorChanged(SensorEvent sensorEvent) {
            //判断当前是加速度传感器还是地磁传感器
            if(sensorEvent.sensor.getType()==Sensor.TYPE_ACCELEROMETER){
                accelerometerValues=sensorEvent.values.clone();
            }else if(sensorEvent.sensor.getType()== Sensor.TYPE_MAGNETIC_FIELD){
                magenticValues=sensorEvent.values.clone();
            }
            float[] R=new float[9];
            float[] values=new float[3];
            SensorManager.getRotationMatrix(R, null, accelerometerValues, magenticValues);
            SensorManager.getOrientation(R,values);
            Log.d("MainActivity","value[0] is"+Math.toDegrees(values[0]));
            degree = Math.toDegrees(values[0]);
        }
        @Override
        public void onAccuracyChanged(Sensor sensor, int i) {
        }
    }; 

最后将该值传给sdk中提供的指南针方法作为参数：

MyLocationData locData = new MyLocationData.Builder()
                    .accuracy(location.getRadius())
                    // 此处设置开发者获取到的方向信息，顺时针0-360  
                    .direction((float)degree).latitude(location.getLatitude())
                    .longitude(location.getLongitude()).build();

完整代码：

import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import andr