1、Android.mk介紹html
Android.mk是Android提供的一種makefile文件,用來指定諸如編譯生成so庫名、引用的頭文件目錄、須要編譯的.c/.cpp文件和.a靜態庫文件等。要掌握jni,就必須熟練掌握Android.mk的語法規範。
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它的基本格式以下:函數
- 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 $(BUILD_SHARED_LIBRARY)
LOCAL_PATH變量制定了該.mk的路徑,$(call my-dir)調用NDK內部的函數得到當前.mk文件的路徑ui
include $(CLEAR_VARS)清空了除了LOCAL_PATH以外的全部LOCAL_xxx變量的值spa
省略號中間就是對於模塊參數的設置,主要包括:模塊名字、模塊源文件、模塊類型、編譯好的模塊存放位置、以及編譯的平臺等.net
include $(BUILD_xxx_xxx)執行NDK的默認腳本,它會收集include $(CLEAR_VARS)腳本後全部定義的LOCAL_xxx變量,而後根據它們來生成模塊。debug
2、Android.mk語法詳解htm
LOCAL_PATH := $(call my-dir)
每一個Android.mk文件必須以定義LOCAL_PATH爲開始。它用於在開發tree中查找源文件。宏my-dir 則由Build System提供。返回包含Android.mk的目錄路徑。
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include $(CLEAR_VARS)
CLEAR_VARS 變量由Build System提供。並指向一個指定的GNU Makefile,由它負責清理不少LOCAL_xxx.
例如:LOCAL_MODULE, LOCAL_SRC_FILES, LOCAL_STATIC_LIBRARIES等等。但不清理LOCAL_PATH.
這個清理動做是必須的,由於全部的編譯控制文件由同一個GNU Make解析和執行,其變量是全局的。因此清理後才能避免相互影響。
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LOCAL_MODULE := hello-jni
LOCAL_MODULE模塊必須定義,以表示Android.mk中的每個模塊。名字必須惟一且不包含空格。Build System會自動添加適當的前綴和後綴。例如,foo,要產生動態庫,則生成libfoo.so. 但請注意:若是模塊名被定爲:libfoo.則生成libfoo.so. 再也不加前綴
LOCAL_MODULE_PATH :=$(TARGET_ROOT_OUT) 指定最後生成的模塊的目標地址
TARGET_ROOT_OUT:根文件系統,路徑爲out/target/product/generic/root
TARGET_OUT:system文件系統,路徑爲out/target/product/generic/system
TARGET_OUT_DATA:data文件系統,路徑爲out/target/product/generic/data
除了上面的這些,NDK還提供了不少其餘的TARGET_XXX_XXX變量,用於將生成的模塊拷貝到輸出目錄的不一樣路徑
默認是TARGET_OUT
LOCAL_SRC_FILES := hello-jni.c
LOCAL_SRC_FILES變量必須包含將要打包如模塊的C/C++ 源碼。沒必要列出頭文件,build System 會自動幫咱們找出依賴文件。缺省的C++源碼的擴展名爲.cpp. 也能夠修改,經過LOCAL_CPP_EXTENSION
include $(BUILD_SHARED_LIBRARY)
BUILD_SHARED_LIBRARY:是Build System提供的一個變量,指向一個GNU Makefile Script。
它負責收集自從上次調用 include $(CLEAR_VARS) 後的全部LOCAL_XXX信息。並決定編譯爲何。
BUILD_STATIC_LIBRARY :編譯爲靜態庫。
BUILD_SHARED_LIBRARY :編譯爲動態庫
BUILD_EXECUTABLE :編譯爲Native C可執行程序
BUILD_PREBUILT :該模塊已經預先編譯
NDK還定義了不少其餘的BUILD_XXX_XXX變量,它們用來指定模塊的生成方式。
3、使用示例
- #編譯靜態庫
- 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)
-
- #編譯動態庫
- 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)
-
- #使用靜態庫
- 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)
-
- #使用動態庫
- 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)
-
-
- #拷貝文件到指定目錄
- 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)
-
-
- #拷貝動態庫到指定目錄
- 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)
參考文章:
http://www.cnblogs.com/wainiwann/p/3837936.html
http://blog.csdn.net/ly131420/article/details/9619269
http://blog.csdn.net/mawl2002/article/details/6118522