查看程序执行过程中所打印的log信息，用于辅助调试排除代码错误。
一、采用NDK安装包下Samples/hello-jni工程做实验
1）修改jni/hello-jni.c文件
#include <android/log.h> __android_log_print(ANDROID_LOG_INFO, "HelloJniTag", "The value is %d", );
2）修改jni/Android.mk文件
LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := hello-jni
LOCAL_SRC_FILES := hello-jni.c
LOCAL_LDLIBS := -llog include $(BUILD_SHARED_LIBRARY)
3）使用eclipse打开当前项目，运行测试，Debug As...
4）在eclipse的logcat监控窗口观察日志信息
二、NDK开发的一般步骤
1）启动eclipse创建android application工程；
2）创建activity应用类（可仿照HelloJni中HelloJni.java）；
3）在activity应用类中加入native函数声明及调用；
public native String stringFromJNI();
/* This is another native method declaration that is *not*
* implemented by 'hello-jni'. This is simply to show that
* you can declare as many native methods in your Java code
* as you want, their implementation is searched in the
* currently loaded native libraries only the first time
* you call them.
*
* Trying to call this function will result in a
* java.lang.UnsatisfiedLinkError exception !
*/
public native String unimplementedStringFromJNI();
/* this is used to load the 'hello-jni' library on application
* startup. The library has already been unpacked into
* /data/data/com.example.hellojni/lib/libhello-jni.so at
* installation time by the package manager.
*/
static {
System.loadLibrary("HelloJni1");
}
4）在命令行模式下使用javah生成jni头文件，并创建c或c++实现文件；
javah -jni -d jni -cp bin/classes:Android-20.jar com.example.hellojni.HelloJni
5）在jni目录下创建Android.mk、Application.mk编辑脚本
#Android.mk LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := hello-jni
LOCAL_SRC_FILES := hello-jni.c
LOCAL_LDLIBS := -llog include $(BUILD_SHARED_LIBRARY)
#Application.mk APP_ABI := all
6）修改AndroidManifest.xml文件，仿照HelloJni添加工程启动的Activity配置项。
7）eclipse启动Debug As...进行调试。