百度地图实现定位图标随手机方向变化而变化，即运用方向传感器
前言： 在安卓《第一行代码》里面关于百度地图sdk的学习中，发现书上的代码只实现到把自己（即定位图标）显示在地图上这一步，而图标的指向是固定的不会随手机方向改变而改变，用起来挺别扭的，故我自己查文档实现了这一功能。
具体实现：一、在书上代码的基础上，自己写一个MyOrientationListener用于监听方向传感器。
public class MyOrientationListener implements SensorEventListener {private Context context;private SensorManager sensorManager;private Sensor sensor;private float lastX; //用于记录最后一次从方向传感器获得的x值private OnOrientationListener onOrientionListener; //内部接口实现回调public interface OnOrientationListener{void onOrientationChanged(float x);}public MyOrientationListener(Context context){this.context=context;}public void setOnOrientionListener(OnOrientationListener onOrientionListener){this.onOrientionListener=onOrientionListener;}@Overridepublic void onSensorChanged(SensorEvent event) {//手机方向改变时调用if (event.sensor.getType()==Sensor.TYPE_ORIENTATION){float x=event.values[SensorManager.DATA_X];if (Math.abs(xlastX)>1.0 //设置条件防止频繁回调{onOrientionListener.onOrientationChanged(x);lastX=x;}}}@Overridepublic void onAccuracyChanged(Sensor sensor, int accuracy) {}public void onStart(){//获取传感器sensor并与onOrientionListener绑定sensorManager=(SensorManager)context.getSystemService(Context.SENSOR_SERVICE);if (sensorManager!=null){sensor=sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);}if(sensor!=null){sensorManager.registerListener(this,sensor,SensorManager.SENSOR_DELAY_UI);}}public void onStop(){sensorManager.unregisterListener(this); //传感器解除绑定}}
二、在Mainactivity中初始化MyOnrientationListener
private MyOrientationListener myOrientationListener;private double mCurrentLantitude; //此刻的纬度值private double mCurrentLongtitude; //此刻的经度值private int mXDirection; //此刻的x值，方向由传感器测出，范围0~360，为手机方向与北极的角度
private void initOrientationListener(){myOrientationListener=new MyOrientationListener(getApplicationContext());myOrientationListener.setOnOrientionListener(new MyOrientationListener.OnOrientationListener() {@Overridepublic void onOrientationChanged(float x) {mXDirection=(int)x;// Log.d("MainActivity"," "+x);builder=new MyLocationData.Builder();builder.longitude(mCurrentLongtitude).latitude(mCurrentLantitude).direction(mXDirection);data=builder.build();baiduMap.setMyLocationData(data); //手机方向改变实时改变图标指向MyLocationConfiguration configuration = new MyLocationConfiguration(MyLocationConfiguration.LocationMode.NORMAL, true, null );baiduMap.setMyLocationConfigeration(configuration);}});}
注意：得把MyLocationConfiguration的构造函数第二个参数设置我为true才可显示方向信息，即图标方向才会改变。
三、管理传感器
protected void onStart(){super.onStart();myOrientationListener.onStart();}
protected void onStop(){super.onStop();myOrientationListener.onStop();}
