这些注册函数是由同目录下的其他.cpp文件中实现,如上面的register_android_server_HelloService(env)这个函数是在com_android_service_HelloService.cpp文件中实现的.那么编译器又是如何知道这点的呢? 答案当然是Android.mk这个文件，打开这个文件，其内容如下:
LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_SRC_FILES:= \ com_android_server_AlarmManagerService.cpp \ com_android_server_BatteryService.cpp \ com_android_server_InputApplicationHandle.cpp \ com_android_server_InputManager.cpp \ com_android_server_InputWindowHandle.cpp \ com_android_server_LightsService.cpp \ com_android_server_PowerManagerService.cpp \ com_android_server_SystemServer.cpp \ com_android_server_UsbDeviceManager.cpp \ com_android_server_UsbHostManager.cpp \ com_android_server_VibratorService.cpp \ com_android_server_location_GpsLocationProvider.cpp \ com_android_server_connectivity_Vpn.cpp \ com_android_server_HelloService.cpp \ onload.cpp LOCAL_C_INCLUDES += \ $(JNI_H_INCLUDE) \ frameworks/base/services \ frameworks/base/core/jni \ external/skia/include/core LOCAL_SHARED_LIBRARIES := \ libandroid_runtime \ libcutils \ libhardware \ libhardware_legacy \ libnativehelper \ libsystem_server \ libutils \ libui \ libinput \ libskia \ libgui \ libusbhost ifeq ($(WITH_MALLOC_LEAK_CHECK),true) LOCAL_CFLAGS += -DMALLOC_LEAK_CHECK endif LOCAL_MODULE:= libandroid_servers include $(BUILD_SHARED_LIBRARY)
在LOCAL_SRC_FILE中给出了所有实现文件(cpp文件)的路径，因此编译就能找到各个注册函数对应的实现文件了.