NDK开发的时候遇到error: undefined reference to 错误

Question

大家好，我在正在将C++的一些代码通过ndk调用到android项目里面去，但是在出现了一个很奇怪的错误;

/bin/ld: ./obj/local/armeabi/objs/TestNDK2/TestNDK2.o: in function Java_com_example_testndk2_MainActivity_stringTestNdk(_JNIEnv*, _jobject*):jni/TestNDK2.cpp:15: error: undefined reference to 'CFeatureExtract::CFeatureExtract()'

collect2: ld returned 1 exit status
make: *** [obj/local/armeabi/libTestNDK2.so] Error 1

我调用jni的文件代码为：

#include <string.h>

#include "FeatureExtract.h"
#include "Output.h"
#include

jstring
Java_com_example_testndk2_MainActivity_stringTestNdk( JNIEnv* env,
jobject thiz )
{

COutput * pout;
pout = new COutput();
CFeatureExtract  *pFtr;
pFtr=new CFeatureExtract();
return (env)->NewStringUTF("Hello from JNI and anbo !");

}

mk文件也编写好了，应该没什么问题，之所以说没问题是因为，我在上面调用了其他cpp文件的 output.cpp和FeatureExtract.cpp等好几个cpp文件，当我把
pFtr=new CFeatureExtract();
这行去掉的时候，会发现不再报错。下面是我的mk的代码：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := libFeatureExtract
LOCAL_SRC_FILES := OnlineFtr.cpp OnlineNorm.cpp FeatureExtract.cpp
LOCAL_C_INCLUDES := $(LOCAL_PATH)/include

include $(BUILD_STATIC_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE := libOutput
LOCAL_SRC_FILES := LQDFR.cpp Classifier.cpp Output.cpp

include $(BUILD_STATIC_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE := TestNDK2
LOCAL_SRC_FILES := TestNDK2.cpp

LOCAL_STATIC_LIBRARIES := libFeatureExtract
LOCAL_STATIC_LIBRARIES := libOutput

include $(BUILD_SHARED_LIBRARY)

最后是我CFeatureExtract构造函数的代码：

CFeatureExtract::CFeatureExtract()

{
nmdir = 0;
nwid = zone*zstep;

pNorm = new COnlineNorm;
pFeatr = new COnlineFtr( nwid );
//edit by anbo
trajnorm = NULL;
new_ptnum =0;
new_ptnum_total=0;
strokeEnd=0;
strokeBegin=0;
countStroke=0;
GaussModel_probability =0;

}

下面是.h头文件的部分声明

class CFeatureExtract{

public:

CFeatureExtract();
~CFeatureExtract();

非常想知道到底哪里错了啊！感谢！

Answer 1

楼主 问题解决了吗？我这边遇到同样的问题。

D:\Chrome_Download\android-ndk-r10d\ndk-build.cmd all
Android NDK: WARNING: APP_PLATFORM android-21 is larger than android:minSdkVersion 10 in ./AndroidManifest.xml

[armeabi] Compile++ thumb: my-ndk <= my-ndk.cpp
[armeabi] SharedLibrary : libmy-ndk.so
jni/my-ndk.cpp:7: error: undefined reference to 'Child::Child()'
collect2.exe: error: ld returned 1 exit status
make.exe: *** [obj/local/armeabi/libmy-ndk.so] Error 1

构造函数 没有定义。明显是定义的。只是使用了多个 *.cpp 文件 链接。 估计就是编译 链接的问题。