android APK更新

菜鸟的博客请多多指教

最近做了一个新功能，更新APK的功能

1、更新APK是一个耗时的任务，我采用了一个服务来做，上次在网上看到服务是在主线程里面，自己也测试了下，数据是真的

所以下载动作还必须在服务里面开一个线程来处理下载任务，在写下载任务的时候，由于经验不够，中间出了很多错，下载要分下载开始，下载中，下载异常，下载结束，

2、在后台下载，对用户来说，是看不见的，无法与用户交流，所以在开启服务的时候我就初始化了一个通知，通知在服务开启是初始化，所以其实通知也是在UI线程中，所以想在下载线程中更新通知进度栏，必须通过机制，来更新通知栏的进度条，但是后来组长又给你我一个需求，在点击通知栏时，在更新界面弹出一个对话框，显示是否要停止更新，这里就涉及到一个新的问题，怎样在Service里面获取Activity呢，找了很多资料，最后找到了一个ActivityManager系统服务，他可以得到指定包的任务栈，得到栈顶的Activity，这样就可以在Service中获取Activity里面了

            String MY_PKG_NAME = "com.example.sunny.text333";
            int i=0;
            ActivityManager manager = (ActivityManager) MyApplication.getInstance().getSystemService(Context.ACTIVITY_SERVICE);
            List<ActivityManager.RunningTaskInfo> list = manager.getRunningTasks(100);
           for (ActivityManager.RunningTaskInfo info: list){
               if(info.topActivity.getPackageName().equals(MY_PKG_NAME) || info.baseActivity.getPackageName().equals(MY_PKG_NAME)){
                break;
               }
               i++;
           }
            ActivityManager.RunningTaskInfo info=list.get(i);
            String className = info.topActivity.getClassName();//得到栈顶的Activity
            Intent intent = null;
            try {
                intent = new Intent(this,Class.forName(className));
                intent.addCategory(Intent.CATEGORY_LAUNCHER);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK| Intent.FLAG_ACTIVITY_SINGLE_TOP);
                Bundle bundle = new Bundle();
                bundle.putString("flag","取消");
                intent.putExtras(bundle);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
                Log.e("没有找到Activity",""+className);
            }
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP
                    |Intent.FLAG_ACTIVITY_NEW_TASK);
        pendingIntent = PendingIntent.getActivity(this, 0,intent,PendingIntent.FLAG_UPDATE_CURRENT);
        notification.contentIntent =pendingIntent;
            Log.e("通知的Activity名称",""+className);

下载线程：

class DownloadThread extends Thread {
        String url;
        MyHandler handler;

        public DownloadThread(String url, MyHandler handler) {
            this.url = url;
            this.handler = handler;
        }

        @Override
        public void run() {

            FileOutputStream fos = null;
            InputStream io = null;
            try {
                handler.sendEmptyMessage(0);
                URL u = new URL(url);
                Log.e("URL","＿＿＿＿＿＿＿＿＿＿＿＿"+u);
                HttpURLConnection connection = (HttpURLConnection) u.openConnection();
                connection.setConnectTimeout(30000);
                connection.setReadTimeout(30000);
                io = connection.getInputStream();

                if (io != null) {
                    File file = new File(Environment.getExternalStorageDirectory() + "/" + "mapp.apk");
                    byte[] buff = new byte[1024];
                    if (file.exists()) {
                        file.delete();
                    } else {
                        file.createNewFile();
                    }
                    fos = new FileOutputStream(file);
                    int readNum = 0;
                    int lastPress = 0;//上一次的进度值
                    int press = 0;//
                    int fileLength = 0;
                    int count = 0;//记录文件的读取个数
                    while (isrunning) {
                        readNum = io.read(buff);
                        fileLength = connection.getContentLength();
                        count += readNum;
                        press = (int) ((float) count / (float) (fileLength - 1) * 100.0);//下载总大小除以总的大小*100
                        BigDecimal bd = new BigDecimal(count);
                        BigDecimal bd1 = new BigDecimal(fileLength - 1);
                        if (readNum == -1 && bd.toPlainString().equals(bd1.toPlainString())) {// 下载完成
                            Log.e("sdas", "下载完成");
                            Message message = new Message();
                            message.obj = file;
                            message.what = 2;
                            handler.sendMessage(message);
                            break;
                        } else if (readNum == -1 && !bd.toPlainString().equals(bd1.toPlainString())) {
                            Log.e("sdas", "下载失败");
                            handler.sendEmptyMessage(4);
                            break;
                        } else if (readNum > 0) {
                            fos.write(buff, 0, readNum);
                           // Log.e("sdas", "readNum:" + readNum);
                            if (press - lastPress >= 1) {
                                lastPress = press;
                              //  Log.e("sdas", "press:" + press);
                                Message message = new Message();
                                message.what = 1;
                                message.obj = press + "";
                                handler.sendMessage(message);
                            }
                        }
                    }
                    fos.flush();
                    fos.close();
                    io.close();
                }
            } catch (MalformedURLException e) {
                handler.sendEmptyMessage(4);
                e.printStackTrace();
            } catch (IOException e) {
                handler.sendEmptyMessage(4);
                e.printStackTrace();
            } finally {
                try {
                    if (fos != null) {
                        fos.flush();
                        fos.close();
                    }
                    if (io != null) {
                        io.close();
                    }
                } catch (IOException e) {

                }

            }
        }
    }

MyHandler的代码：

class MyHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {

                    super.handleMessage(msg);
            if (msg != null) {
                switch (msg.what) {
                    case 0:// 初始化通知栏和进度条
                        views.setTextViewText(R.id.tvProcess, "开始下载……");
                        views.setTextColor(R.id.tvProcess, Color.BLACK);
                        views.setProgressBar(R.id.app_down_progressBar, 100, 0, false);
                        notification.defaults = Notification.DEFAULT_LIGHTS;
                        notification.contentView = views;
                        nm.notify(NOTIFICATIO_UPDATE_SOFT, notification);
                        MyApplication.getInstance().setIsupdateing(true);
                        break;
                    case 1:
                        int download_precent = Integer.parseInt(msg.obj.toString());// 获取下载进度
                        // 更新状态栏上的下载进度信息
                        views.setTextViewText(R.id.tvProcess, "已下载" + download_precent + "%");
                        views.setTextColor(R.id.tvProcess, Color.BLACK);
                        views.setProgressBar(R.id.app_down_progressBar, 100, download_precent, false);
                        notification.defaults = Notification.DEFAULT_LIGHTS;
                        notification.contentView = views;
                        nm.notify(NOTIFICATIO_UPDATE_SOFT, notification);
                        MyApplication.getInstance().setIsupdateing(true);

                        break;
                    case 2:
                        MyApplication.getInstance().setIsupdateing(false);
                      /*  if( unIntallapk()){
                            Log.e("文件卸载",""+unIntallapk());

                        }*/
                        Instanll((File) msg.obj);

                        nm.cancel(NOTIFICATIO_UPDATE_SOFT);
                        // 停止掉当前的服务
                        stopSelf();
                        break;
                    case 3:// 停止下载
                        MyApplication.getInstance().setIsupdateing(false);
                        // 停止掉当前的服务
                        nm.cancel(NOTIFICATIO_UPDATE_SOFT);
                        stopSelf();
                        break;
                    case 4:// 下载异常
                        MyApplication.getInstance().setIsupdateing(false);
                        views.setTextViewText(R.id.tvProcess, "" + "已停止下载");
                        views.setTextColor(R.id.tvProcess, Color.BLUE);
                        // 在任务栏不被用户手动删除
                        notification.flags = Notification.FLAG_AUTO_CANCEL;
                        // 调用系统默认的声音提示以及震动
                        notification.defaults = Notification.DEFAULT_ALL;
                        notification.contentView = views;
                        nm.cancel(NOTIFICATIO_UPDATE_SOFT);
                        nm.notify(NOTIFICATIO_UPDATE_SOFT, notification);
                        break;
                    default:
                        break;
                }
            }
        }
    }