JNI 中打印变量

1.封装个log.h

#ifndef __MULTI_TRACE_H__

#define __MULTI_TRACE_H__

#ifdef ANDROID_NDK_BUILD

#define LOG_TAG "NATIVE NDK INFO"

#include <android/log.h> // only use in NDK

#define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__))

#define LOGD(...) ((void)__android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__))

#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__))

#define LOGW(...) ((void)__android_log_print(ANDROID_LOG_WARN, LOG_TAG, __VA_ARGS__))

#elif defined ANDROID_SOURCE_BUILD

#define LOG_TAG "NATIVE SRC INFO"

extern "C" {

#include <cutils/log.h> // only use in ANDROID SOURCE

}

#define LOGE(...) LOG(LOG_ERROR, LOG_TAG, __VA_ARGS__)

#define LOGD(...) LOG(LOG_DEBUG, LOG_TAG, __VA_ARGS__)

#define LOGI(...) LOG(LOG_INFO, LOG_TAG, __VA_ARGS__)

#define LOGW(...) LOG(LOG_WARN, LOG_TAG, __VA_ARGS__)

#elif defined IOS_PLATFORM_BUILD

#define LOGE printf

#define LOGD printf

#define LOGI printf

#define LOGW printf

#elif defined WP_PLATFORM_BUILD

#define LOG_TAG "NATIVE WINDOWS PHONE"

#define LOG_ERROR "ERROR"

#define LOG_DEBUG "DEBUG"

#define LOG_INFOR "INFOR"

#define LOG_WARN "WARN"

void LOG(const char* status, const char* tag, const char* format, ...);

#define LOGE(...) LOG(LOG_ERROR, LOG_TAG, __VA_ARGS__)

#define LOGD(...) LOG(LOG_DEBUG, LOG_TAG, __VA_ARGS__)

#define LOGI(...) LOG(LOG_INFO, LOG_TAG, __VA_ARGS__)

#define LOGW(...) LOG(LOG_WARN, LOG_TAG, __VA_ARGS__)

#else

#define LOGE printf

#define LOGD printf

#define LOGI printf

#define LOGW printf

#endif

#endif

2.在 Android.mk 中配置

LOCAL_PATH := $(call my-dir)    // 设置为当前目录

include $(CLEAR_VARS)    // 清空变量

LOCAL_MODULE    := ApkPatchLibrary  // 最终生成的 .so 文件 会是次名钱夹 lib (如这个名为 libxxx, 生成的.so文件包名就是此名)

LOCAL_CFLAGS =  -DANDROID_NDK_BUILD -D__STDC_FORMAT_MACROS -D__STDC_INT64__     // 设置这句相当于每个c/c++文件中声明了 xxxxx(-Dxxxxx)

LOCAL_CXXFLAGS :=

LOCAL_C_INCLUDES := $(LOCAL_PATH)

LOCAL_SRC_FILES := com_lib_utils_Patch.c   // 编译的c/c++文件

LOCAL_LDLIBS := -lz -llog  // 需要加上 这个日志才会打印出来，-l 是固定声明，（如：-lz标示加载系统 z.so包， -llog标示加载系统 log.so包）

include $(BUILD_SHARED_LIBRARY)   // 设置声明 动态库

3.打印日志，请看例子：

JNIEXPORT jint JNICALL Java_com_lib_utils_PatchUtils_patch(JNIEnv *env,

jobject obj, jstring old, jstring new, jstring patch) {

char * ch[4];

ch[0] = "bspatch";

ch[1] = (char*) ((*env)->GetStringUTFChars(env, old, 0));

ch[2] = (char*) ((*env)->GetStringUTFChars(env, new, 0));

ch[3] = (char*) ((*env)->GetStringUTFChars(env, patch, 0));

LOGD("11111111111111111111");

const char *str = (*env)->GetStringUTFChars(env, old, 0);

const char *strnew = (*env)->GetStringUTFChars(env, new, 0);

const char *strpatch = (*env)->GetStringUTFChars(env, patch, 0);

LOGD("The first is %s", str);

LOGD("The second is %s", strnew);

LOGD("The third  is %s", strpatch);

LOGD("11111111111111111111");

int ret = applypatch(4, ch);

(*env)->ReleaseStringUTFChars(env, old, ch[1]);

(*env)->ReleaseStringUTFChars(env, new, ch[2]);

(*env)->ReleaseStringUTFChars(env, patch, ch[3]);

return ret;

}

这样就可以打印出 old, new，patch 这三个参数（变量）的值了。