Android Framework阅读经验

• Context.getSystemService(Context.XXXX)，在/android/frameworks/base/core/java/android/app/SystemServiceRegistry.java类里面，直接搜索Context.XXXX，如果这里也搜不到，就全局搜索一下Context.XXXX，在注册的地方会有创建的入口，以Context.WINDOW_SERVICE为例

//比如WindowManagerImpl的创建
registerService(Context.WINDOW_SERVICE, WindowManager.class,new CachedServiceFetcher<WindowManager>() {@Overridepublic WindowManager createService(ContextImpl ctx) {return new WindowManagerImpl(ctx);}});

• /android/frameworks/base/core/java/com/android/internal/os/BinderInternal.java下的native方法，对应实现路径在android/frameworks/base/core/jni/android_util_Binder.cpp

public static final native IBinder getContextObject();//对应static jobject android_os_BinderInternal_getContextObject(JNIEnv* env, jobject clazz)
{sp<IBinder> b = ProcessState::self()->getContextObject(NULL);return javaObjectForIBinder(env, b);
}