一.Android 的简介:

1.Android.mk文件首先需要指定LOCAL_PATH变量，用于查找源文件。由于一般情况下Android.mk和需要编译的源文件在同一目录下，所以定义成如下形式：

LOCAL_PATH:=$(call my-dir)

上面的语句的意思是将LOCAL_PATH变量定义成本文件所在目录路径。

2. Android.mk中可以定义多个编译模块，每个编译模块都是以include $(CLEAR_VARS)开始，以include $(BUILD_XXX)结束。

include $(CLEAR_VARS)

CLEAR_VARS由编译系统提供，指定让GNU MAKEFILE为你清除除LOCAL_PATH以外的所有LOCAL_XXX变量，如LOCAL_MODULE、LOCAL_SRC_FILES、 LOCAL_SHARED_LIBRARIES、LOCAL_STATIC_LIBRARIES等

include $(BUILD_STATIC_LIBRARY)表示编译成静态库
include $(BUILD_SHARED_LIBRARY)表示编译成动态库。
include $(BUILD_EXECUTABLE)表示编译成可执行程序

3.举例如下(frameworks/base/libs/audioflinger/Android.mk)

(1).

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)  
ifeq ($(AUDIO_POLICY_TEST),true)
  ENABLE_AUDIO_DUMP := true
endif
LOCAL_SRC_FILES:= 
    AudioHardwareGeneric.cpp 
    AudioHardwareStub.cpp 
    AudioHardwareInterface.cpp
ifeq ($(ENABLE_AUDIO_DUMP),true)
  LOCAL_SRC_FILES += AudioDumpInterface.cpp
  LOCAL_CFLAGS += -DENABLE_AUDIO_DUMP
endif
LOCAL_SHARED_LIBRARIES := 
    libcutils 
    libutils 
    libbinder 
    libmedia 
    libhardware_legacy
ifeq ($(strip $(BOARD_USES_GENERIC_AUDIO)),true)
  LOCAL_CFLAGS += -DGENERIC_AUDIO
endif
LOCAL_MODULE:= libaudiointerface
ifeq ($(BOARD_HAVE_BLUETOOTH),true)
  LOCAL_SRC_FILES += A2dpAudioInterface.cpp
  LOCAL_SHARED_LIBRARIES += liba2dp
  LOCAL_CFLAGS += -DWITH_BLUETOOTH -DWITH_A2DP
  LOCAL_C_INCLUDES += $(call include-path-for, bluez)
endifinclude $(BUILD_STATIC_LIBRARY)  模块一编译成静态库

(2)

include $(CLEAR_VARS) 
LOCAL_SRC_FILES:=               
    AudioPolicyManagerBase.cpp
LOCAL_SHARED_LIBRARIES := 
    libcutils 
    libutils 
    libmedia
ifeq ($(TARGET_SIMULATOR),true)
LOCAL_LDLIBS += -ldl
else
LOCAL_SHARED_LIBRARIES += libdl
endif
LOCAL_MODULE:= libaudiopolicybase
ifeq ($(BOARD_HAVE_BLUETOOTH),true)
  LOCAL_CFLAGS += -DWITH_A2DP
endif
ifeq ($(AUDIO_POLICY_TEST),true)
  LOCAL_CFLAGS += -DAUDIO_POLICY_TEST
endif
include $(BUILD_STATIC_LIBRARY) 模块二编译成静态库

(3)

include $(CLEAR_VARS)
LOCAL_SRC_FILES:=               
    AudioFlinger.cpp            
    AudioMixer.cpp.arm          
    AudioResampler.cpp.arm      
    AudioResamplerSinc.cpp.arm  
    AudioResamplerCubic.cpp.arm 
    AudioPolicyService.cpp
LOCAL_SHARED_LIBRARIES := 
    libcutils 
    libutils 
    libbinder 
    libmedia 
    libhardware_legacy
ifeq ($(strip $(BOARD_USES_GENERIC_AUDIO)),true)
  LOCAL_STATIC_LIBRARIES += libaudiointerface libaudiopolicybase
  LOCAL_CFLAGS += -DGENERIC_AUDIO
else
  LOCAL_SHARED_LIBRARIES += libaudio libaudiopolicy
endif
ifeq ($(TARGET_SIMULATOR),true)
LOCAL_LDLIBS += -ldl
else
LOCAL_SHARED_LIBRARIES += libdl
endif
LOCAL_MODULE:= libaudioflinger
ifeq ($(BOARD_HAVE_BLUETOOTH),true)
  LOCAL_CFLAGS += -DWITH_BLUETOOTH -DWITH_A2DP
  LOCAL_SHARED_LIBRARIES += liba2dp
endif
ifeq ($(AUDIO_POLICY_TEST),true)
  LOCAL_CFLAGS += -DAUDIO_POLICY_TEST
endif
ifeq ($(TARGET_SIMULATOR),true)
    ifeq ($(HOST_OS),linux)
        LOCAL_LDLIBS += -lrt -lpthread
    endif
endif
ifeq ($(BOARD_USE_LVMX),true)
    LOCAL_CFLAGS += -DLVMX
    LOCAL_C_INCLUDES += vendor/nxp
    LOCAL_STATIC_LIBRARIES += liblifevibes
    LOCAL_SHARED_LIBRARIES += liblvmxservice
#    LOCAL_SHARED_LIBRARIES += liblvmxipc
endif
include $(BUILD_SHARED_LIBRARY) 模块三编译成动态库

二.编译总结:

1.编译一个简单的APK(LocalPackage.apk)

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
# Build all java files in the java subdirectory
LOCAL_SRC_FILES := $(call all-subdir-java-files)
# Name of the APK to build
LOCAL_PACKAGE_NAME := LocalPackage
# Tell it to build an APK
include $(BUILD_PACKAGE)

2.编译一个依赖静态(static-library.jar)文件的APK(LocalPackage.apk)

  LOCAL_PATH := $(call my-dir)
  include $(CLEAR_VARS)
  # List of static libraries to include in the package
  LOCAL_STATIC_JAVA_LIBRARIES := static-library
  # Build all java files in the java subdirectory
  LOCAL_SRC_FILES := $(call all-subdir-java-files)
  # Name of the APK to build
  LOCAL_PACKAGE_NAME := LocalPackage
  # Tell it to build an APK
  include $(BUILD_PACKAGE)

注：LOCAL_STATIC_JAVA_LIBRARIES 后面应是你的APK程序所需要的JAVA库的JAR文件名。

3.编译一个需要platform key签名的APK(LocalPackage.apk)

  LOCAL_PATH := $(call my-dir)
  include $(CLEAR_VARS)
  # Build all java files in the java subdirectory
  LOCAL_SRC_FILES := $(call all-subdir-java-files)
  # Name of the APK to build
  LOCAL_PACKAGE_NAME := LocalPackage
  LOCAL_CERTIFICATE := platform
  # Tell it to build an APK
  include $(BUILD_PACKAGE)

注：LOCAL_CERTIFICATE 后面应该是签名文件的文件名

4.编译一个需要特殊vendor key签名的APK(LocalPackage.apk)

  LOCAL_PATH := $(call my-dir)
  include $(CLEAR_VARS)
  # Build all java files in the java subdirectory
  LOCAL_SRC_FILES := $(call all-subdir-java-files)
  # Name of the APK to build
  LOCAL_PACKAGE_NAME := LocalPackage
  LOCAL_CERTIFICATE := vendor/example/certs/app
  # Tell it to build an APK
  include $(BUILD_PACKAGE

5.装载一个普通的第三方APK(LocalModuleName.apk)

  LOCAL_PATH := $(call my-dir)
  include $(CLEAR_VARS)
  # Module name should match apk name to be installed.
  LOCAL_MODULE := LocalModuleName
  LOCAL_SRC_FILES := $(LOCAL_MODULE).apk
  LOCAL_MODULE_CLASS := APPS
  LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
  LOCAL_CERTIFICATE := platform
  include $(BUILD_PREBUILT)

6.装载需要.so（动态库）的第三方APK

LOCAL_PATH := $(my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := baiduinput_android_v1.1_1000e
LOCAL_SRC_FILES := $(LOCAL_MODULE).apk
LOCAL_MODULE_CLASS := APPS
LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
LOCAL_CERTIFICATE := platform
include $(BUILD_PREBUILT)
 
#################################################################
####### copy the library to /system/lib #########################
#################################################################

include $(CLEAR_VARS)
LOCAL_MODULE := libinputcore.so
LOCAL_MODULE_CLASS := SHARED_LIBRARIES
LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)
LOCAL_SRC_FILES := lib/$(LOCAL_MODULE)
OVERRIDE_BUILD_MODULE_PATH := $(TARGET_OUT_INTERMEDIATE_LIBRARIES)
include $(BUILD_PREBUILT)

7.编译一个静态java库

  LOCAL_PATH := $(call my-dir)
  include $(CLEAR_VARS)
  # Build all java files in the java subdirectory
  LOCAL_SRC_FILES := $(call all-subdir-java-files)
  # Any libraries that this library depends on
  LOCAL_JAVA_LIBRARIES := android.test.runner
  # The name of the jar file to create
  LOCAL_MODULE := sample
  # Build a static jar file.
  include $(BUILD_STATIC_JAVA_LIBRARY)

注：LOCAL_JAVA_LIBRARIES表示生成的java库的jar文件名。