Android Sensor ARCH--getSystemService

Refs: http://www.cnblogs.com/lcw/p/3402770.html

https://source.android.com/devices/architecture

PATH:frameworks/base/core/java/android

1. SensorManager.java

     getSystemService

2. ContextImpl.java

(当我们new一个对象时，static修饰的成员变量首先被初始化，随后是普通成员，最后调用类的构造方法完成初始化)

SystemServiceRegistry类中的静态代码块完成系统服务的注册

 

3. SystemServiceRegistry.java

CachedServiceFetcher

StaticServiceFetcher