Android应用如何监听自己是否被卸载及卸载反馈功能的实现(第二版)

  昨天发了一篇有关监听自己是否被卸载和卸载反馈功能实现的博客,地址如下:http://www.cnblogs.com/zealotrouge/p/3157126.html,发出去后收到几位热心网友的建议,在此特别感谢@cccode @泡泡糖 @Alexia(minmin) @0x00.pl ,你们的建议就是我前进的动力。

  昨天的技术方案有一个硬伤,就是每1s就需要轮询目录是否存在,对资源消耗较大,第二版将会解决这一问题。思路是今天想到了一个Android自API1就有的一个类FileObserver,这个类用于监听某个文件的变化状态,如果是目录,这个类还可以监听其子目录及子目录文件的变化状态,通过阅读FileObserver源码,发现其实现利用了Linux内核中一个重要的机制inotify,它是一个内核用于通知用户空间程序文件系统变化的机制,详情可参考http://en.wikipedia.org/wiki/Inotify,里面对inotify有比较详细的说明。

  使用inotify的好处就在于不需要每1s的轮询,这样就不会无谓地消耗系统资源,使用inotify时会用read()方法阻塞进程,直到收到IN_DELETE通知,此时进程重新被唤醒,执行反馈处理流程。

  由于Activity代码和Android.mk文件和第一版并无实质性区别,这里就不贴代码了,直接贴出C端进程的实现代码吧。

核心——native方法头文件:

 

 1 /* 头文件begin */
 2 #include <jni.h>
 3 #include <stdlib.h>
 4 #include <stdio.h>
 5 #include <string.h>
 6 #include <android/log.h>
 7 #include <unistd.h>
 8 #include <sys/inotify.h>
 9 #include <fcntl.h>
10 /* 头文件end */
11 
12 /* 宏定义begin */
13 //清0宏
14 #define MEM_ZERO(pDest, destSize) memset(pDest, 0, destSize)
15 
16 //LOG宏定义
17 #define LOG_INFO(tag, msg) __android_log_write(ANDROID_LOG_INFO, tag, msg)
18 #define LOG_DEBUG(tag, msg) __android_log_write(ANDROID_LOG_DEBUG, tag, msg)
19 #define LOG_WARN(tag, msg) __android_log_write(ANDROID_LOG_WARN, tag, msg)
20 #define LOG_ERROR(tag, msg) __android_log_write(ANDROID_LOG_ERROR, tag, msg)
21 /* 宏定义end */
22 
23 #ifndef _Included_main_activity_UninstalledObserverActivity
24 #define _Included_main_activity_UninstalledObserverActivity
25 #ifdef __cplusplus
26 extern "C" {
27 #endif
28 
29 #undef main_activity_UninstalledObserverActivity_MODE_PRIVATE
30 #define main_activity_UninstalledObserverActivity_MODE_PRIVATE 0L
31 #undef main_activity_UninstalledObserverActivity_MODE_WORLD_READABLE
32 #define main_activity_UninstalledObserverActivity_MODE_WORLD_READABLE 1L
33 #undef main_activity_UninstalledObserverActivity_MODE_WORLD_WRITEABLE
34 #define main_activity_UninstalledObserverActivity_MODE_WORLD_WRITEABLE 2L
35 #undef main_activity_UninstalledObserverActivity_MODE_APPEND
36 #define main_activity_UninstalledObserverActivity_MODE_APPEND 32768L
37 #undef main_activity_UninstalledObserverActivity_MODE_MULTI_PROCESS
38 #define main_activity_UninstalledObserverActivity_MODE_MULTI_PROCESS 4L
39 #undef main_activity_UninstalledObserverActivity_BIND_AUTO_CREATE
40 #define main_activity_UninstalledObserverActivity_BIND_AUTO_CREATE 1L
41 #undef main_activity_UninstalledObserverActivity_BIND_DEBUG_UNBIND
42 #define main_activity_UninstalledObserverActivity_BIND_DEBUG_UNBIND 2L
43 #undef main_activity_UninstalledObserverActivity_BIND_NOT_FOREGROUND
44 #define main_activity_UninstalledObserverActivity_BIND_NOT_FOREGROUND 4L
45 #undef main_activity_UninstalledObserverActivity_BIND_ABOVE_CLIENT
46 #define main_activity_UninstalledObserverActivity_BIND_ABOVE_CLIENT 8L
47 #undef main_activity_UninstalledObserverActivity_BIND_ALLOW_OOM_MANAGEMENT
48 #define main_activity_UninstalledObserverActivity_BIND_ALLOW_OOM_MANAGEMENT 16L
49 #undef main_activity_UninstalledObserverActivity_BIND_WAIVE_PRIORITY
50 #define main_activity_UninstalledObserverActivity_BIND_WAIVE_PRIORITY 32L
51 #undef main_activity_UninstalledObserverActivity_BIND_IMPORTANT
52 #define main_activity_UninstalledObserverActivity_BIND_IMPORTANT 64L
53 #undef main_activity_UninstalledObserverActivity_BIND_ADJUST_WITH_ACTIVITY
54 #define main_activity_UninstalledObserverActivity_BIND_ADJUST_WITH_ACTIVITY 128L
55 #undef main_activity_UninstalledObserverActivity_CONTEXT_INCLUDE_CODE
56 #define main_activity_UninstalledObserverActivity_CONTEXT_INCLUDE_CODE 1L
57 #undef main_activity_UninstalledObserverActivity_CONTEXT_IGNORE_SECURITY
58 #define main_activity_UninstalledObserverActivity_CONTEXT_IGNORE_SECURITY 2L
59 #undef main_activity_UninstalledObserverActivity_CONTEXT_RESTRICTED
60 #define main_activity_UninstalledObserverActivity_CONTEXT_RESTRICTED 4L
61 #undef main_activity_UninstalledObserverActivity_RESULT_CANCELED
62 #define main_activity_UninstalledObserverActivity_RESULT_CANCELED 0L
63 #undef main_activity_UninstalledObserverActivity_RESULT_OK
64 #define main_activity_UninstalledObserverActivity_RESULT_OK -1L
65 #undef main_activity_UninstalledObserverActivity_RESULT_FIRST_USER
66 #define main_activity_UninstalledObserverActivity_RESULT_FIRST_USER 1L
67 #undef main_activity_UninstalledObserverActivity_DEFAULT_KEYS_DISABLE
68 #define main_activity_UninstalledObserverActivity_DEFAULT_KEYS_DISABLE 0L
69 #undef main_activity_UninstalledObserverActivity_DEFAULT_KEYS_DIALER
70 #define main_activity_UninstalledObserverActivity_DEFAULT_KEYS_DIALER 1L
71 #undef main_activity_UninstalledObserverActivity_DEFAULT_KEYS_SHORTCUT
72 #define main_activity_UninstalledObserverActivity_DEFAULT_KEYS_SHORTCUT 2L
73 #undef main_activity_UninstalledObserverActivity_DEFAULT_KEYS_SEARCH_LOCAL
74 #define main_activity_UninstalledObserverActivity_DEFAULT_KEYS_SEARCH_LOCAL 3L
75 #undef main_activity_UninstalledObserverActivity_DEFAULT_KEYS_SEARCH_GLOBAL
76 #define main_activity_UninstalledObserverActivity_DEFAULT_KEYS_SEARCH_GLOBAL 4L
77 
78 /*
79  * Class:     main_activity_UninstalledObserverActivity
80  * Method:    init
81  * Signature: ()V
82  */
83 JNIEXPORT void JNICALL Java_main_activity_UninstalledObserverActivity_init(JNIEnv *, jobject);
84 
85 #ifdef __cplusplus
86 }
87 #endif
88 #endif

 

核心——native方法实现:

 

 1 /* 头文件begin */
 2 #include "main_activity_UninstalledObserverActivity.h"
 3 /* 头文件end */
 4 
 5 #ifdef __cplusplus
 6 extern "C" {
 7 #endif
 8 
 9 /* 内全局变量begin */
10 static char c_TAG[] = "UninstalledObserverActivity.init";
11 static jboolean b_IS_COPY = JNI_TRUE;
12 /* 内全局变量 */
13 
14 /*
15  * Class:     main_activity_UninstalledObserverActivity
16  * Method:    init
17  * Signature: ()V
18  */
19 JNIEXPORT void JNICALL Java_main_activity_UninstalledObserverActivity_init(JNIEnv *env, jobject obj)
20 {
21     jstring tag = (*env)->NewStringUTF(env, c_TAG);
22 
23     //初始化log
24     LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
25             , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "init OK"), &b_IS_COPY));
26 
27     //fork子进程,以执行轮询任务
28     pid_t pid = fork();
29     if (pid < 0)
30     {
31         //出错log
32         LOG_ERROR((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
33                 , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "fork failed !!!"), &b_IS_COPY));
34     }
35     else if (pid == 0)
36     {
37         //子进程注册"/data/data/pym.test.uninstalledobserver"目录监听器
38         int fileDescriptor = inotify_init();
39         if (fileDescriptor < 0)
40         {
41             LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
42                     , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "inotify_init failed !!!"), &b_IS_COPY));
43 
44              exit(1);
45         }
46 
47         int watchDescriptor;
48         watchDescriptor = inotify_add_watch(fileDescriptor, "/data/data/pym.test.uninstalledobserver", IN_DELETE);
49         if (watchDescriptor < 0)
50         {
51             LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
52                     , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "inotify_add_watch failed !!!"), &b_IS_COPY));
53 
54             exit(1);
55         }
56 
57         //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
58         void *p_buf = malloc(sizeof(struct inotify_event));
59         if (p_buf == NULL)
60         {
61             LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
62                     , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "malloc failed !!!"), &b_IS_COPY));
63 
64             exit(1);
65         }
66         //开始监听
67         LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
68                     , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "start observer"), &b_IS_COPY));
69         size_t readBytes = read(fileDescriptor, p_buf, sizeof(struct inotify_event));
70 
71         //read会阻塞进程,走到这里说明收到目录被删除的事件,注销监听器
72         free(p_buf);
73         inotify_rm_watch(fileDescriptor, IN_DELETE);
74 
75         //目录不存在log
76         LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
77                     , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "uninstalled"), &b_IS_COPY));
78 
79         //执行命令am start -a android.intent.action.VIEW -d http://shouji.360.cn/web/uninstall/uninstall.html
80         execlp("am", "am", "start", "-a", "android.intent.action.VIEW", "-d", "http://shouji.360.cn/web/uninstall/uninstall.html", (char *)NULL);
81     }
82     else
83     {
84         //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
85     }
86 }
87 
88 #ifdef __cplusplus
89 }
90 #endif

 

 

 

 

posted @ 2013-06-27 20:42 热气球 阅读(...) 评论(...) 编辑 收藏