一个应用被用户卸载肯定是有理由的,而开发者却未必能得知这一重要的理由,毕竟用户很少会主动反馈建议,多半就是用得不爽就卸,如果能在被卸载后获取到用户的一些反馈,那对开发者进一步改进应用是非常有利的。目前据我所知,国内的Android应用中实现这一功能的只有360手机卫士、360平板卫士,那么如何实现这一功能的?
我们可以把实现卸载反馈的问题转化为监听自己是否被卸载,只有得知自己被卸载,才可以设计相应的反馈处理流程。以下的列表是我在研究这一问题的思路:
1,注册BroadcastReceiver,监听"android.intent.action.PACKAGE_REMOVED"系统广播
结果:NO。未写代码,直接分析,卸载的第一步就是退出当前应用的主进程,而此广播是在已经卸载完成后才发出的,此时主进程都没有了,去哪onReceive()呢?
2,若能收到"将要卸载XX包"的系统广播,在主进程被退出之前就抢先进行反馈处理就好了,可惜没有这样的系统广播,不过经过调研,倒是发现了一个办法,读取系统log,当日志中包含"android.intent.action.DELETE"和自己的包名时,意味着自己将要被卸载。
结果:NO。调试时发现此方法有两个缺陷,(1)点击设置中的卸载按钮即发出此Intent,此时用户尚未在弹框中确认卸载;(2)pm命令卸载不出发此Intent,意味着被诸如手机安全管家,豌豆荚等软件卸载时,无法提前得知卸载意图。
3,由于时间点不容易把控,所以干脆不依赖系统广播或log,考虑到卸载过程会删除"/data/data/包名"目录,我们可以用线程直接轮询这个目录是否存在,以此为依据判断自己是否被卸载。
结果:NO。同方法1,主进程退出,相应的线程必定退出,线程还没等到判断目录是否存在就已经被销毁了。
4,改用C端进程轮询"/data/data/包名"目录是否存在
结果:YES。借助Java端进程fork出来的C端进程在应用被卸载后不会被销毁。
OK,上代码!
Activity启动时fork出C端进程轮询目录:
1 package main.activity;
2
3 import pym.test.uninstalledmoniter.R;
4 import android.app.Activity;
5 import android.os.Bundle;
6 import android.util.Log;
7
8 /**
9 * @author pengyiming
10 * @note 监听此应用是否被卸载,若被卸载则弹出卸载反馈
11 *
12 */
13
14 public class UninstalledMoniterActivity extends Activity
15 {
16 /* 数据段begin */
17 private static final String TAG = "UninstalledMoniterActivity";
18 /* 数据段end */
19
20 /* 函数段begin */
21 private native void init();
22 static
23 {
24 Log.d(TAG, "load libuninstalled_moniter");
25 System.loadLibrary("uninstalled_moniter");
26 }
27
28 @Override
29 public void onCreate(Bundle savedInstanceState)
30 {
31 super.onCreate(savedInstanceState);
32 Log.d(TAG, "onCreate");
33
34 setContentView(R.layout.uninstalled_moniter_layout);
35
36 init();
37 }
38 /* 函数段end */
39 }
核心——native方法头文件:
1 /* 头文件begin */
2 #include <jni.h>
3 #include <stdio.h>
4 #include <string.h>
5 #include <android/log.h>
6 #include <unistd.h>
7 /* 头文件end */
8
9 /* 宏定义begin */
10 //清0宏
11 #define MEM_ZERO(pDest, destSize) memset(pDest, 0, destSize)
12
13 //LOG宏定义
14 #define LOG_INFO(tag, msg) __android_log_write(ANDROID_LOG_INFO, tag, msg)
15 #define LOG_DEBUG(tag, msg) __android_log_write(ANDROID_LOG_DEBUG, tag, msg)
16 #define LOG_WARN(tag, msg) __android_log_write(ANDROID_LOG_WARN, tag, msg)
17 #define LOG_ERROR(tag, msg) __android_log_write(ANDROID_LOG_ERROR, tag, msg)
18 /* 宏定义end */
19
20 #ifndef _Included_main_activity_UninstalledMoniterActivity
21 #define _Included_main_activity_UninstalledMoniterActivity
22 #ifdef __cplusplus
23 extern "C" {
24 #endif
25
26 #undef main_activity_UninstalledMoniterActivity_MODE_PRIVATE
27 #define main_activity_UninstalledMoniterActivity_MODE_PRIVATE 0L
28 #undef main_activity_UninstalledMoniterActivity_MODE_WORLD_READABLE
29 #define main_activity_UninstalledMoniterActivity_MODE_WORLD_READABLE 1L
30 #undef main_activity_UninstalledMoniterActivity_MODE_WORLD_WRITEABLE
31 #define main_activity_UninstalledMoniterActivity_MODE_WORLD_WRITEABLE 2L
32 #undef main_activity_UninstalledMoniterActivity_MODE_APPEND
33 #define main_activity_UninstalledMoniterActivity_MODE_APPEND 32768L
34 #undef main_activity_UninstalledMoniterActivity_MODE_MULTI_PROCESS
35 #define main_activity_UninstalledMoniterActivity_MODE_MULTI_PROCESS 4L
36 #undef main_activity_UninstalledMoniterActivity_BIND_AUTO_CREATE
37 #define main_activity_UninstalledMoniterActivity_BIND_AUTO_CREATE 1L
38 #undef main_activity_UninstalledMoniterActivity_BIND_DEBUG_UNBIND
39 #define main_activity_UninstalledMoniterActivity_BIND_DEBUG_UNBIND 2L
40 #undef main_activity_UninstalledMoniterActivity_BIND_NOT_FOREGROUND
41 #define main_activity_UninstalledMoniterActivity_BIND_NOT_FOREGROUND 4L
42 #undef main_activity_UninstalledMoniterActivity_BIND_ABOVE_CLIENT
43 #define main_activity_UninstalledMoniterActivity_BIND_ABOVE_CLIENT 8L
44 #undef main_activity_UninstalledMoniterActivity_BIND_ALLOW_OOM_MANAGEMENT
45 #define main_activity_UninstalledMoniterActivity_BIND_ALLOW_OOM_MANAGEMENT 16L
46 #undef main_activity_UninstalledMoniterActivity_BIND_WAIVE_PRIORITY
47 #define main_activity_UninstalledMoniterActivity_BIND_WAIVE_PRIORITY 32L
48 #undef main_activity_UninstalledMoniterActivity_BIND_IMPORTANT
49 #define main_activity_UninstalledMoniterActivity_BIND_IMPORTANT 64L
50 #undef main_activity_UninstalledMoniterActivity_BIND_ADJUST_WITH_ACTIVITY
51 #define main_activity_UninstalledMoniterActivity_BIND_ADJUST_WITH_ACTIVITY 128L
52 #undef main_activity_UninstalledMoniterActivity_CONTEXT_INCLUDE_CODE
53 #define main_activity_UninstalledMoniterActivity_CONTEXT_INCLUDE_CODE 1L
54 #undef main_activity_UninstalledMoniterActivity_CONTEXT_IGNORE_SECURITY
55 #define main_activity_UninstalledMoniterActivity_CONTEXT_IGNORE_SECURITY 2L
56 #undef main_activity_UninstalledMoniterActivity_CONTEXT_RESTRICTED
57 #define main_activity_UninstalledMoniterActivity_CONTEXT_RESTRICTED 4L
58 #undef main_activity_UninstalledMoniterActivity_RESULT_CANCELED
59 #define main_activity_UninstalledMoniterActivity_RESULT_CANCELED 0L
60 #undef main_activity_UninstalledMoniterActivity_RESULT_OK
61 #define main_activity_UninstalledMoniterActivity_RESULT_OK -1L
62 #undef main_activity_UninstalledMoniterActivity_RESULT_FIRST_USER
63 #define main_activity_UninstalledMoniterActivity_RESULT_FIRST_USER 1L
64 #undef main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_DISABLE
65 #define main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_DISABLE 0L
66 #undef main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_DIALER
67 #define main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_DIALER 1L
68 #undef main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_SHORTCUT
69 #define main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_SHORTCUT 2L
70 #undef main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_SEARCH_LOCAL
71 #define main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_SEARCH_LOCAL 3L
72 #undef main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_SEARCH_GLOBAL
73 #define main_activity_UninstalledMoniterActivity_DEFAULT_KEYS_SEARCH_GLOBAL 4L
74
75 /*
76 * Class: main_activity_UninstalledMoniterActivity
77 * Method: init
78 * Signature: ()V
79 */
80 JNIEXPORT void JNICALL Java_main_activity_UninstalledMoniterActivity_init(JNIEnv *, jobject);
81
82 #ifdef __cplusplus
83 }
84 #endif
85 #endif
核心——native方法实现:
1 /* 头文件begin */
2 #include "main_activity_UninstalledMoniterActivity.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[] = "UninstalledMoniterActivity.init";
11 static jboolean b_IS_COPY = JNI_TRUE;
12 /* 内全局变量 */
13
14 /*
15 * Class: main_activity_UninstalledMoniterActivity
16 * Method: init
17 * Signature: ()V
18 */
19 JNIEXPORT void JNICALL Java_main_activity_UninstalledMoniterActivity_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 error !!!"), &b_IS_COPY));
34 }
35 else if (pid == 0)
36 {
37 //子进程轮询"/data/data/pym.test.uninstalledmoniter"目录是否存在,若不存在则说明已被卸载
38 while (1)
39 {
40 FILE *p_file = fopen("/data/data/pym.test.uninstalledmoniter", "r");
41 if (p_file != NULL)
42 {
43 fclose(p_file);
44
45 //目录存在log
46 LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
47 , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "I'm OK !!!"), &b_IS_COPY));
48
49 sleep(1);
50 }
51 else
52 {
53 //目录不存在log
54 LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY)
55 , (*env)->GetStringUTFChars(env, (*env)->NewStringUTF(env, "I'm NOT OK !!!"), &b_IS_COPY));
56
57 //执行命令am start -a android.intent.action.VIEW -d http://shouji.360.cn/web/uninstall/uninstall.html
58 execlp("am", "am", "start", "-a", "android.intent.action.VIEW", "-d", "http://shouji.360.cn/web/uninstall/uninstall.html", (char *)NULL);
59 }
60 }
61 }
62 else
63 {
64 //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
65 }
66 }
67
68 #ifdef __cplusplus
69 }
70 #endif
注1:为了调试方便,包含<android/log.h>,使得so在执行过程中也可以像Java端一样方便得打出log。相应的mk文件需要加上以下两句声明
LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog
注2:代码中引用了360手机卫士的反馈地址,仅供大家学习、测试使用~~~
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