Android應用被卸載後，自動使用 浏覽器打開指定連接

本文，提供“Android應用被卸載後，自動使用 浏覽器打開指定連接”的方法。
原理：在安卓程序中某處，基於JNI調用C代碼開啟一個子進程監控應用在系統中的文件目錄，一旦應用被卸載，該目錄將會被系統刪除，此時觸發子進程執行相關代碼（本例調用浏覽器執行打開一個連接）
1、在安卓項目下創建jni目錄
2、在jni目錄下創建文件observer.c

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
#include 
#include 

#include 
#include 
#include 
#include 
#include 
#include 
#include 

/* 宏定義begin */
//清0宏
#define MEM_ZERO(pDest, destSize) memset(pDest, 0, destSize)

//LOG宏定義
#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)

/* 內全局變量begin */
static char c_TAG[] = "onEvent";
static jboolean b_IS_COPY = JNI_TRUE;

/* 暴露給Android代碼調用的natvie方法 */
jstring Java_com_zgy_catchuninstallself_UninstallObserver_startWork(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子進程，以執行輪詢任務
    pid_t pid = fork();
    if (pid < 0) {
        //出錯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) {
        //子進程注冊目錄監聽器
        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);
        }

        //分配緩存，以便讀取event，緩存大小=一個struct inotify_event的大小，這樣一次處理一個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);
        }
        //開始監聽
        LOG_DEBUG((*env)->GetStringUTFChars(env, tag, &b_IS_COPY),
                (*env)->GetStringUTFChars(env,
                        (*env)->NewStringUTF(env, "start observer"),
                        &b_IS_COPY));
        //read會阻塞進程，
        size_t readBytes = read(fileDescriptor, p_buf,
                sizeof(struct inotify_event));

        //走到這裡說明收到目錄被刪除的事件，注銷監聽器
        free(p_buf);
        inotify_rm_watch(fileDescriptor, IN_DELETE);

        //目錄不存在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以上的系統由於用戶權限管理更嚴格，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);
        }
        //擴展：可以執行其他shell命令，am(即activity manager)，可以打開某程序、服務，broadcast intent，等等

    } else {
        //父進程直接退出，使子進程被init進程領養，以避免子進程僵死
    }

    return (*env)->NewStringUTF(env, "Hello from JNI !");
}

3、在jni目錄下創建文件Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE:=observer
LOCAL_SRC_FILES:=observer.c
LOCAL_C_INCLUDES:= $(LOCAL_PATH)/include
LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog
include $(BUILD_SHARED_LIBRARY)

4、在創建natvie方法，並在Android中調用JNI方法

package com.zgy.catchuninstallself;



public class UninstallObserver {

    static{
        System.loadLibrary("observer");
    }
    public static native String startWork(String path, String url, int version);//path：data/data/[packageNmae]   ；   url:跳轉的頁面，需要http://或https://開頭
}

String url = "http://www.baidu.com";
UninstallObserver.startWork(path, url, android.os.Build.VERSION.SDK_INT);

注：JNI方法在被重復調用的情況下，我沒有測試是否會重復開啟多個子進程，這個留給大家測試。