1.通过jni实现函数

//LOG宏定义#define LOG_INFO(tag, msg) __android_log_write(ANDROID_LOG_INFO, tag, msg)#define LOG_DEBUG(tag, msg) __android_log_write(ANDROID_LOG_DEBUG, tag, msg)#define LOG_WARN(tag, msg) __android_log_write(ANDROID_LOG_WARN, tag, msg)#define LOG_ERROR(tag, msg) __android_log_write(ANDROID_LOG_ERROR, tag, msg)/* 内全局变量begin */static char c_TAG[] = "onEvent";static jboolean b_IS_COPY = JNI_TRUE;jstring Java_com_example_uninstallself_Observer_register(JNIEnv* env,		jobject thiz, jstring path, jstring url, jint version) {	jstring tag = (*env)->NewStringUTF(env, c_TAG);	//初始化log	LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),			(*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "init OK"),					&b_IS_COPY));	//fork子进程，以执行轮询任务	pid_t pid = fork();	if (pid < 0) {		//出错log		LOG_ERROR((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),				(*env)->GetStringUTFChars(env,						(*env)->NewStringUTF(env, "fork failed !!!"),						&b_IS_COPY));	} else if (pid == 0) {		//子进程注册目录监听器		int fileDescriptor = inotify_init();		if (fileDescriptor < 0) {			LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),					(*env)->GetStringUTFChars(env,							(*env)->NewStringUTF(env,									"inotify_init failed !!!"), &b_IS_COPY));			exit(1);		}		int watchDescriptor;		watchDescriptor = inotify_add_watch(fileDescriptor,				(*env)->GetStringUTFChars(env, path, NULL), IN_DELETE);		if (watchDescriptor < 0) {			LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),					(*env)->GetStringUTFChars(env,							(*env)->NewStringUTF(env,									"inotify_add_watch failed !!!"),							&b_IS_COPY));			exit(1);		}		//分配缓存，以便读取event，缓存大小=一个struct inotify_event的大小，这样一次处理一个event		void *p_buf = malloc(sizeof(struct inotify_event));		if (p_buf == NULL) {			LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),					(*env)->GetStringUTFChars(env,							(*env)->NewStringUTF(env, "malloc failed !!!"),							&b_IS_COPY));			exit(1);		}		//开始监听		LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),				(*env)->GetStringUTFChars(env,						(*env)->NewStringUTF(env, "start observer"),						&b_IS_COPY));		//read会阻塞进程，		size_t readBytes = read(fileDescriptor, p_buf,				sizeof(struct inotify_event));		//走到这里说明收到目录被删除的事件，注销监听器		free(p_buf);		inotify_rm_watch(fileDescriptor, IN_DELETE);		//目录不存在log		LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),				(*env)->GetStringUTFChars(env,						(*env)->NewStringUTF(env, "uninstalled"), &b_IS_COPY));		if (version >= 17) {			//4.2以上的系统由于用户权限管理更严格，需要加上 --user 0			execlp("am", "am", "start", "--user", "0", "-a",					"android.intent.action.VIEW", "-d",					(*env)->GetStringUTFChars(env, url, NULL), (char *) NULL);		} else {			execlp("am", "am", "start", "-a", "android.intent.action.VIEW",					"-d", (*env)->GetStringUTFChars(env, url, NULL),					(char *) NULL);		}		//扩展：可以执行其他shell命令，am(即activity manager)，可以打开某程序、服务，broadcast intent，等等	} else {		//父进程直接退出，使子进程被init进程领养，以避免子进程僵死	}	return (*env)->NewStringUTF(env, "Hello from JNI !");}

2.定义UninstallObserver

public class UninstallObserver {	static{		System.loadLibrary("observer");	}	/***	 * 	 * @param path 需要监听的文件路径，可用 getApplicationContext().getFilesDir().getPath()	 * @param url 卸载调转http	 * @param version android.os.Build.VERSION.SDK_INT	 * @return	 */	public static native String register(String path, String url, int version);}

3.简单使用

@Overrideprotected void onCreate(Bundle savedInstanceState) {	super.onCreate(savedInstanceState);	setContentView(R.layout.activity_main);	Toast.makeText(getApplicationContext(),			getApplicationContext().getFilesDir().getPath() + "," + Build.VERSION.SDK_INT, 1).show();	long a = System.currentTimeMillis();	String str = UninstallObserver.register(getApplicationContext().getFilesDir().getPath(), "http://www.baidu.com",			android.os.Build.VERSION.SDK_INT);	long b = System.currentTimeMillis();	Toast.makeText(getApplicationContext(), str+","+(b-a), 1).show();}