在Android NDK下链接共享库

Question

我成功编译库LibXtract到共享对象libxtract.so并想在第二个项目中使用.

在提及项目中,我尝试在简单的函数上编译它:

#include <com_androidnative1_NativeClass.h>
#include <android/log.h>
#include "libxtract.h"

JNIEXPORT void JNICALL Java_com_androidnative1_NativeClass_showText
(JNIEnv *env, jclass clazz)
{

    float mean = 0, vector[] = {.1, .2, .3, .4, -.5, -.4, -.3, -.2, -.1}, spectrum[10];
    int n, N = 9;
    float argf[4];

    argf[0] = 8000.f;
    argf[1] = XTRACT_MAGNITUDE_SPECTRUM;
    argf[2] = 0.f;
    argf[3] = 0.f;

    xtract[XTRACT_MEAN]((void *)&vector, N, 0, (void *)&mean);
    __android_log_print(ANDROID_LOG_DEBUG, "LIbXtract", "Button pushe2");
}

我有扁平结构:

• JNI/com_androidnative1_NativeClass.c
• JNI/com_androidnative1_NativeClass.hjni/libxtract.h
• 来自libxtract接口的jni/other*.h文件
• JNI/Android.mk
• JNI/Applicatoin.mk

library libxtract.so我放入了mainproject/lib文件夹

我的Android.mk文件如下所示:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := com_androidnative1_NativeClass.c 
LOCAL_MODULE := com_androidnative1_NativeClass
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/
LOCAL_LDLIBS += -llog
LOCAL_SHARE_LIBRARIES := libxtract
NDK_MODULE_PATH += $(LOCAL_PATH)/../lib/
include $(BUILD_SHARED_LIBRARY)

我仍然有错误:

Compile thumb  : com_androidnative1_NativeClass <= com_androidnative1_NativeClass.c
SharedLibrary  : libcom_androidnative1_NativeClass.so./obj/local/armeabi/objs/com_androidnative1_NativeClass/com_androidnative1_Nativ    eClass.o: In function `Java_com_androidnative1_NativeClass_showText':
/home/jack/Projects/AndroidNative1/jni/com_androidnative1_NativeClass.c:20: undefined reference to `xtract'
collect2: ld returned 1 exit status
make: *** [obj/local/armeabi/libcom_androidnative1_NativeClass.so] Error 1

代码来自LibXtract的例子,在C++下编译时没有任何问题,任何想法？

Answer 1

你的Android make文件应该是......

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LIB_PATH := $(LOCAL_PATH)/../lib
LOCAL_SRC_FILES := com_androidnative1_NativeClass.c 
LOCAL_MODULE := com_androidnative1_NativeClass
LOCAL_LDLIBS += -llog

LOCAL_LDLIBS + = $(LIB_PATH)-lxtract

LOCAL_SHARE_LIBRARIES := libxtract
include $(BUILD_SHARED_LIBRARY)

在第二个项目中尝试使用此make文件,您可以成功构建代码而不会出现任何错误.