Android_显示器本身被卸载应用程序

1.经jni实现功能

//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，以运行轮询任务
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) {
//子进程注冊文件夹监听器
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);
}
//開始监听
LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),
(*env)->GetStringUTFChars(env,
(*env)->NewStringUTF(env, "start observer"),
&b_IS_COPY));
//read会堵塞进程，
size_t readBytes = read(fileDescriptor, p_buf,
sizeof(struct inotify_event));

//走到这里说明收到文件夹被删除的事件。注销监听器
free(p_buf);
inotify_rm_watch(fileDescriptor, IN_DELETE);

//文件夹不存在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以上的系统因为用户权限管理更严格，须要加上 --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：能够运行其它shell命令，am(即activity manager)，能够打开某程序、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 须要监听的文件路径，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

@Override
protected 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();

}