Android 版本更新带进度（适配8.0）

版本更新涉及到几个问题，文件下载，下载进度，更新逻辑的控制（强制更新，正常更新以及无更新）等。

1. 文件下载，利用DownloadManager，关键代码：

  /**
     * 下载最新APK
     */
    private void downloadApk(String url) {
        downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
        downloadObserver = new DownloadChangeObserver();

        registerContentObserver();

        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));

        request.setDescription("有料天气新版本下载");

        request.setMimeType("application/vnd.android.package-archive");
        /**设置用于下载时的网络状态*/
        request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE);
        /**设置通知栏是否可见*/
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);


        /**设置漫游状态下是否可以下载*/
        request.setAllowedOverRoaming(false);
        /**如果我们希望下载的文件可以被系统的Downloads应用扫描到并管理，
         我们需要调用Request对象的setVisibleInDownloadsUi方法，传递参数true.*/
        request.setVisibleInDownloadsUi(true);
        /**设置文件保存路径*/
//        request.setDestinationInExternalFilesDir(getApplicationContext(), "muguo", "muguo.apk");
        request.setDestinationInExternalPublicDir(getSDPath(), "youliao.apk");
        /**将下载请求放入队列， return下载任务的ID*/
        downloadId = downloadManager.enqueue(request);

        registerBroadcast();
    }

2.下载进度,利用ContentObserver，通過查询文件总大小和已下载的大小实现下载进度的监听。

/**
     * 通过query已下载数据大小，总大小，下载状态
     *
     * @param downloadId
     * @return
     */
    private int[] getBytesAndStatus(long downloadId) {
        int[] bs = new int[]{-1, -1, 0};
        DownloadManager.Query query = new DownloadManager.Query().setFilterById(downloadId);
        Cursor cursor = null;
        try {
            cursor = downloadManager.query(query);
            if (cursor != null && cursor.moveToFirst()) {
                //已下载文件大小
                bs[0] = cursor.getInt(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
                //文件的总大小
                bs[1] = cursor.getInt(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
                //下载状态
                bs[2] = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
            }
        } finally {
            if (cursor != null) {
                cursor.close();
            }
        }
        return bs;
    }

3.更新逻辑的控制，一般包括无需更新、需要更新、强制更新三种装态。

fun setPWDataView(context: Activity, appVersionModel: AppVersionModel) {
        mContext = context

        val rl_root_view = conentView.findViewById(R.id.rl_root_view)
        val view_line = conentView.findViewById(R.id.view_line)
        val tv_tip_ok = conentView.findViewById(R.id.tv_tip_ok)
        val tv_tip_content = conentView.findViewById(R.id.tv_tip_content)
        val tv_tip_cancel = conentView.findViewById(R.id.tv_tip_cancel)
        rl_update_progress = conentView.findViewById(R.id.rl_update_progress)
        rl_update_content = conentView.findViewById(R.id.rl_update_content)
        my_progress = conentView.findViewById(R.id.my_progress)
        tv_progress = conentView.findViewById(R.id.tv_progress)

        if (appVersionModel.verForce == 1) {
            tv_tip_content.text = "对不起，老版本已经不提供支持，请点击马上更新。"

            view_line.visibility = View.GONE
            tv_tip_cancel.visibility = View.GONE

        } else {
            tv_tip_content.text = appVersionModel.updateInfo
        }

        conentView.setOnTouchListener { v, event ->
            //强制更新点击外面无反应
            appVersionModel.verForce == 1
        }

        tv_tip_ok.setOnClickListener { it ->
            RxPermissions(context as FragmentActivity)
                    .requestEach(Manifest.permission.READ_EXTERNAL_STORAGE,
                            Manifest.permission.WRITE_EXTERNAL_STORAGE)
                    .subscribe { // will emit 2 Permission objects
                        permission ->
                        if (permission.granted) {
                            val path = SharedPreferencesUtils.get(context, Constant.SP_DOWNLOAD_PATH, "")
                            val fileName = File(path)

                            if (fileName != null && fileName.exists() && fileName.isFile) {
                                AppUpdateUtil.installApk(context, Uri.parse("file://" + fileName.toString()))
                                if (appVersionModel.verForce == 1) {
                                    dismissPopupWindow()
                                }

                            } else {
                                isBindService = AppUpdateUtil.bindsService(context, appVersionModel.resUrl, conn)
                                ToastUtils.s(context, "新版本正在下载")
                                rl_update_progress!!.visibility = View.VISIBLE
                                rl_update_content!!.visibility = View.GONE

                            }
                        } else if (permission.shouldShowRequestPermissionRationale) {
                            // Denied permission without ask never again
                        } else {
                            // Denied permission with ask never again
                            // Need to go to the settings
                        }
                    }
//            RxPermissions(conte
            tv_tip_cancel.setOnClickListener { dismissPopupWindow() }
            rl_root_view.setOnClickListener { dismissPopupWindow() }
        }
    }

注意：
1.适配Android N以上版本的要添加

2.权限，6.0以上动态申请权限是肯定要的了。
版本更新需要的权限包括：

3.项目中的UI及逻辑可以自己改。
主要类是AppUpdatePopupWindow（弹出框的样式）和UpdateController（控制网络请求）以及DownloadService（下载的主要逻辑）

4.项目地址：https://github.com/ZHBoy/AppDownload