如何在同一个Android.mk中编译两个不同的库,将其中一个链接到另一个

Question

我有2个不同库的源代码,FooMain和FooSecondary.FooSecond由FooMain使用,因此,makefile必须编译First FooSecondary,然后编译FooMain,然后将FooSecondary链接到FooMain.

我的Android.mk是:

LOCAL_PATH:= $(call my-dir)

# Foo Secondary lib:

# Clear vars
include $(CLEAR_VARS)
# Target Build
LOCAL_ARM_MODE := arm   
# Library Name          
LOCAL_MODULE := FooSecondary        
# Set All SRC_FILES Together            
SRC_FILES := $(wildcard $(LOCAL_PATH)/FooSecondary/src/*.c)
SRC_FILES := $(SRC_FILES:$(LOCAL_PATH)/%=%)     
LOCAL_SRC_FILES = $(SRC_FILES)
# Enable Log support
LOCAL_LDLIBS = -llog    
# C   Flags - Max optimization              
LOCAL_CFLAGS := -O3 -mno-thumb
# C++ Flags - Max optimization          
LOCAL_CPPFLAGS := -O3 -mno-thumb
# Compile as Shared Library     
include $(BUILD_SHARED_LIBRARY)     

# Foo Secondary lib:

# Clear vars
include $(CLEAR_VARS)
# Include OpenCV
include 3rdparty/OpenCV-2.4.3-rc-android-sdk/sdk/native/jni/OpenCV.mk
# Target Build
LOCAL_ARM_MODE := arm   
# Library Name          
LOCAL_MODULE := FooMain     
# Set All SRC_FILES Together            
SRC_FILES := $(wildcard $(LOCAL_PATH)/FooMain/src/*.cpp)
SRC_FILES := $(SRC_FILES:$(LOCAL_PATH)/%=%)     
LOCAL_SRC_FILES = $(SRC_FILES)
LOCAL_SHARED_LIBRARIES := libFooSecondary
LOCAL_LDLIBS := -L$(LOCAL_PATH)/../libs/armeabi 
LOCAL_LDLIBS += -lz -lm -ldl -lGLESv2 -lEGL -llog -lFooSecondary
LOCAL_CFLAGS := -O2 -mno-thumb -Wno-write-strings
LOCAL_CPPFLAGS := -O2 -mno-thumb -Wno-write-strings
# Compile as Shared Library     
include $(BUILD_SHARED_LIBRARY) 

我的Application.mk是:

APP_CPPFLAGS := -frtti -fexceptions
APP_STL := gnustl_static
APP_ABI := armeabi-v7a

但是,当我使用ndk-build编译Android.mk时,我得到下一个错误:

Compile arm    : libFooSecondary <= *.c
SharedLibrary  : libFooSecondary.so
Install        : libFooSecondary.so => libs/armeabi-v7a/libFooSecondary.so
SharedLibrary  : libFooMain.so

/home/user/android-ndk-r8/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/../lib/gcc/arm-linux-androideabi/4.4.3/../../../../arm-linux-androideabi/bin/ld: cannot find -lFooSecondary

collect2: ld returned 1 exit status
make: *** [obj/local/armeabi-v7a/libFooMain.so] Error 1

如果正确编译和安装,为什么找不到libFooSecondary.so？

另外,如果LOCAL_MODULE名称改变,例如,第一个是LOCAL_MODULE:= zname,第二个是LOCAL_MODULE:= aname,先编译第二个,我不知道为什么.

Answer 1

你Android.mk看起来很奇怪.它分配LOCAL_PATH到哪里？没有必要分配LOCAL_CPPFLAGS重复LOCAL_CFLAGS,因为ndk-build在C++命令行上放置两组标志.

要更好地了解NDK如何解释您的Application.mk和Android.mk,您可以运行

ndk-build V=1

这将回显所有已执行的命令,包括编译和链接,以及NDK构建所分配的所有参数.