[英]Using JsonCpp on X-Cross platform library
I'm making a library in C++ with OpenCV and JsonCpp towards building a library for Android and iOS. 我正在使用OpenCV和JsonCpp用C ++创建一个库,以构建适用于Android和iOS的库。
On testing my library for Android, I'm making the JNI files but when I try to load the library I'm getting 在为Android测试我的库时,我正在制作JNI文件,但是当我尝试加载该库时,我得到了
java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "_ZN4Json6WriterD2Ev" referenced by "libXYZ.so"...
java.lang.UnsatisfiedLinkError:dlopen失败:找不到由“ libXYZ.so”引用的符号“ _ZN4Json6WriterD2Ev” ...
and that's because I think I'm not building my Json library very well. 那是因为我认为我没有很好地构建我的Json库。
The library that I use is this one: https://github.com/open-source-parsers/jsoncpp 我使用的库就是这个库: https : //github.com/open-source-parsers/jsoncpp
My Android.mk is: 我的Android.mk是:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
OPENCV_CAMERA_MODULES:=off
OPENCV_INSTALL_MODULES:=on
include $(LOCAL_PATH)/jsoncpp/Android.mk
include /Users/localmac/Desktop/AndroidDevelopment/OpenCV-2.4.9-android-sdk/sdk/native/jni/OpenCV.mk
OPENCV_LIB_TYPE:=SHARED
LOCAL_C_INCLUDES += $(LOCAL_PATH)
LOCAL_C_INCLUDES += /Users/localmac/mylibrary/OpenCVtry/
LOCAL_C_INCLUDES += /Users/localmac/Desktop/RD/OpenCVtry/Libraries/jsoncpp-master/include
LOCAL_ALLOW_UNDEFINED_SYMBOLS := true
LOCAL_MODULE := libXYZ
LOCAL_SRC_FILES := androidClass.cpp main.cpp utils.cpp
LOCAL_LDLIBS += -llog -ldl
include $(BUILD_SHARED_LIBRARY)
I have no idea of how to do this. 我不知道该怎么做。
Thank you in advance. 先感谢您。
EDIT it's not the NDK Compiling's fault. 编辑这不是NDK编译的错误。
Even if I compile the JsonCpp, I get the 即使我编译了JsonCpp,我也得到了
java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "_ZN4Json6WriterD2Ev" referenced by "libXYZ.so"...
java.lang.UnsatisfiedLinkError:dlopen失败:找不到由“ libXYZ.so”引用的符号“ _ZN4Json6WriterD2Ev” ...
EDIT My jsoncpp/Android.mk : 编辑我的jsoncpp / Android.mk:
LOCAL_PATH := $(call my-dir)
LOCAL_PATH:= $(调用my-dir)
include $(CLEAR_VARS)
包括$(CLEAR_VARS)
LOCAL_CPP_EXTENSION := .cpp LOCAL_MODULE := libJsoncpp
LOCAL_CPP_EXTENSION:= .cpp LOCAL_MODULE:= libJsoncpp
LOCAL_C_INCLUDES := $(LOCAL_PATH)/jsoncpp/include
LOCAL_C_INCLUDES:= $(LOCAL_PATH)/ jsoncpp / include
LOCAL_SRC_FILES := src/lib_json/json_reader.cpp \\ src/lib_json/json_value.cpp \\ src/lib_json/json_writer.cpp
LOCAL_SRC_FILES:= src / lib_json / json_reader.cpp \\ src / lib_json / json_value.cpp \\ src / lib_json / json_writer.cpp
include $(BUILD_SHARED_LIBRARY)
包括$(BUILD_SHARED_LIBRARY)
You're not linking against Jsoncpp in your makefile. 您不会在makefile中链接Jsoncpp。 You should add the following line:
您应该添加以下行:
LOCAL_SHARED_LIBRARIES := libJsoncpp
before the last include $(BUILD_SHARED_LIBRARY)
. 在最后一个之前
include $(BUILD_SHARED_LIBRARY)
。
You must specify module names for this variable (and its sister LOCAL_STATIC_LIBRARIES
), that is, what you specified for the LOCAL_MODULE
variable. 你必须为这个变量(及其姊妹指定模块名称
LOCAL_STATIC_LIBRARIES
),也就是说,你指定的什么LOCAL_MODULE
变量。
Also, that spares you from specifiying the includes in the LOCAL_C_INCLUDE
variable (as the makefile will include them directly when specifying the library in the variable I mentioned at the top of my post). 另外,这避免了您在
LOCAL_C_INCLUDE
变量中指定包含内容(因为在我在文章顶部提到的变量中指定库时,makefile将直接包含它们)。
EDIT: For the sake of completeness, I'll add that you can specify multiple libraries like that: 编辑:为了完整起见,我将添加您可以指定多个类似的库:
LOCAL_SHARED_LIBRARIES = libJsoncpp \
libOpenCV \
...
and the same goes for LOCAL_STATIC_LIBRARIES
. LOCAL_STATIC_LIBRARIES
。
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