The four instructions for using “logcat” in JNI:
1. Include the header file “android/log.h” as follows:
#include <android/log.h>
2. Define the need functions as follows:
I only the one.
#define LOGD(…) __android_log_print(ANDROID_LOG_DEBUG , “liblog”,__VA_ARGS__)
Other functions is below:
#define LOGV(…) __android_log_print(ANDROID_LOG_VERBOSE, “liblog”,__VA_ARGS__)
#define LOGI(…) __android_log_print(ANDROID_LOG_INFO, “liblog”,__VA_ARGS__)
#define LOGW(…) __android_log_print(ANDROID_LOG_WARN, “liblog”,__VA_ARGS__)
#define LOGE(…) __android_log_print(ANDROID_LOG_ERROR, “liblog”,__VA_ARGS__)
3. You can use the LOGD function in the source code.
LOGD(“Debug Message is from JNI”);
4. Add some words in the file “Android.mk”
LOCAL_LDLIBS := -L$(SYSROOT)/usr/lib -llog
P.S. I refer some information that tell me add the line under “LOCAL_PATH := $(call my-dir)”. When I build the JNI code, the undefined reference always happened. So I move the line above the line “include $(BUILD_SHARED_LIBRARY)”, then the error disappeared. I think that the reason is the path of the directory.
