Android.mk用法详解 | 您所在的位置:网站首页 › ps中毫米和像素 › Android.mk用法详解 |
一、Android.mk介绍 Android.mk是Android提供的一种makefile文件,用来指定诸如编译生成so库名、引用的头文件目录、需要编译的.c/.cpp文件和.a静态库文件等。要掌握jni,就必须熟练掌握Android.mk的语法规范。 它的基本格式如下: [cpp] view plain copy print? LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) ................ LOCAL_xxx := xxx LOCAL_MODULE := hello-jni LOCAL_SRC_FILES := hello-jni.c LOCAL_xxx := xxx ................ include $(BUILD_SHARED_LIBRARY)LOCAL_PATH变量制定了该.mk的路径,$(call my-dir)调用NDK内部的函数获得当前.mk文件的路径 include $(CLEAR_VARS)清空了除了LOCAL_PATH之外的所有LOCAL_xxx变量的值 省略号中间就是对于模块参数的设置,主要包括:模块名字、模块源文件、模块类型、编译好的模块存放位置、以及编译的平台等 include $(BUILD_xxx_xxx)执行NDK的默认脚本,它会收集include $(CLEAR_VARS)脚本后所有定义的LOCAL_xxx变量,然后根据它们来生成模块。 二、Android.mk语法详解 LOCAL_PATH := $(call my-dir) 每个Android.mk文件必须以定义LOCAL_PATH为开始。它用于在开发tree中查找源文件。宏my-dir 则由Build System提供。返回包含Android.mk的目录路径。
include $(CLEAR_VARS) CLEAR_VARS 变量由Build System提供。并指向一个指定的GNU Makefile,由它负责清理很多LOCAL_xxx. 例如:LOCAL_MODULE, LOCAL_SRC_FILES, LOCAL_STATIC_LIBRARIES等等。但不清理LOCAL_PATH. 这个清理动作是必须的,因为所有的编译控制文件由同一个GNU Make解析和执行,其变量是全局的。所以清理后才能避免相互影响。
LOCAL_MODULE := hello-jni LOCAL_MODULE模块必须定义,以表示Android.mk中的每一个模块。名字必须唯一且不包含空格。Build System会自动添加适当的前缀和后缀。例如,foo,要产生动态库,则生成libfoo.so. 但请注意:如果模块名被定为:libfoo.则生成libfoo.so. 不再加前缀
LOCAL_MODULE_PATH :=$(TARGET_ROOT_OUT) 指定最后生成的模块的目标地址 TARGET_ROOT_OUT:根文件系统,路径为out/target/product/generic/root TARGET_OUT:system文件系统,路径为out/target/product/generic/system TARGET_OUT_DATA:data文件系统,路径为out/target/product/generic/data 除了上面的这些,NDK还提供了很多其他的TARGET_XXX_XXX变量,用于将生成的模块拷贝到输出目录的不同路径 默认是TARGET_OUT LOCAL_SRC_FILES := hello-jni.c LOCAL_SRC_FILES变量必须包含将要打包如模块的C/C++ 源码。不必列出头文件,build System 会自动帮我们找出依赖文件。缺省的C++源码的扩展名为.cpp. 也可以修改,通过LOCAL_CPP_EXTENSION
include $(BUILD_SHARED_LIBRARY) BUILD_SHARED_LIBRARY:是Build System提供的一个变量,指向一个GNU Makefile Script。 它负责收集自从上次调用 include $(CLEAR_VARS) 后的所有LOCAL_XXX信息。并决定编译为什么。 BUILD_STATIC_LIBRARY :编译为静态库。 BUILD_SHARED_LIBRARY :编译为动态库 BUILD_EXECUTABLE :编译为Native C可执行程序 BUILD_PREBUILT :该模块已经预先编译 NDK还定义了很多其他的BUILD_XXX_XXX变量,它们用来指定模块的生成方式。 三、使用示例 [cpp] view plain copy print? #编译静态库 LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE = libhellos LOCAL_CFLAGS = $(L_CFLAGS) LOCAL_SRC_FILES = hellos.c LOCAL_C_INCLUDES = $(INCLUDES) LOCAL_SHARED_LIBRARIES := libcutils LOCAL_COPY_HEADERS_TO := libhellos LOCAL_COPY_HEADERS := hellos.h include $(BUILD_STATIC_LIBRARY) #编译动态库 LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE = libhellod LOCAL_CFLAGS = $(L_CFLAGS) LOCAL_SRC_FILES = hellod.c LOCAL_C_INCLUDES = $(INCLUDES) LOCAL_SHARED_LIBRARIES := libcutils LOCAL_COPY_HEADERS_TO := libhellod LOCAL_COPY_HEADERS := hellod.h include $(BUILD_SHARED_LIBRARY) #使用静态库 LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := hellos LOCAL_STATIC_LIBRARIES := libhellos LOCAL_SHARED_LIBRARIES := LOCAL_LDLIBS += -ldl LOCAL_CFLAGS := $(L_CFLAGS) LOCAL_SRC_FILES := mains.c LOCAL_C_INCLUDES := $(INCLUDES) include $(BUILD_EXECUTABLE) #使用动态库 LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := hellod LOCAL_MODULE_TAGS := debug LOCAL_SHARED_LIBRARIES := libc libcutils libhellod LOCAL_LDLIBS += -ldl LOCAL_CFLAGS := $(L_CFLAGS) LOCAL_SRC_FILES := maind.c LOCAL_C_INCLUDES := $(INCLUDES) include $(BUILD_EXECUTABLE) #拷贝文件到指定目录 LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := bt_vendor.conf LOCAL_MODULE_CLASS := ETC LOCAL_MODULE_PATH := $(TARGET_OUT)/etc/bluetooth LOCAL_MODULE_TAGS := eng LOCAL_SRC_FILES := $(LOCAL_MODULE) include $(BUILD_PREBUILT) #拷贝动态库到指定目录 LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) #the data or lib you want to copy LOCAL_MODULE := libxxx.so LOCAL_MODULE_CLASS := SHARED_LIBRARIES LOCAL_MODULE_PATH := $(ANDROID_OUT_SHARED_LIBRARIES) LOCAL_SRC_FILES := lib/$(LOCAL_MODULE ) OVERRIDE_BUILD_MODULE_PATH := $(TARGET_OUT_INTERMEDIATE_LIBRARIES) include $(BUILD_PREBUILT)参考文章: http://www.cnblogs.com/wainiwann/p/3837936.html http://blog.csdn.net/ly131420/article/details/9619269 http://blog.csdn.net/mawl2002/article/details/6118522 |
CopyRight 2018-2019 实验室设备网 版权所有 |