DownloadManager downloadManager = (DownloadManager)context.getSystemService(Context.DOWNLOAD_SERVICE);
構(gòu)建下載請(qǐng)求

DownloadManager.Request request = new DownloadManager.Request(Uri.parse("目標(biāo)文件下載地址"));
//設(shè)置目標(biāo)文件夾，如果你想在系統(tǒng)的storage目錄下載一個(gè)testDownload/test/test.apk
request.setDestinationInExternalPublicDir("testDownload", "test/test.apk");
//設(shè)置下載所需的網(wǎng)絡(luò)環(huán)境,設(shè)置了移動(dòng)網(wǎng)絡(luò)和WiFi環(huán)境下均能下載 request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_MOBILE | DownloadManager.Request.NETWORK_WIFI);
//通知欄設(shè)置
//顯示在通知欄
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE);

//設(shè)置文件類型為apk類型，當(dāng)downloadManager調(diào)用openFile時(shí)會(huì)喚起相應(yīng)的程序
request.setMimeType("application/cn.trinea.download.file");
 //開始下載,得到一個(gè)唯一的downloadId，大有用處
long downloadId = downloadManager.enqueue(request);

private int[] getBytesAndStatus(long downloadId) {

    //構(gòu)建一個(gè)數(shù)組，存放已下載文件大小、總大小、下載狀態(tài)
    int[] bytesAndStatus = new int[]{
        -1, -1, 0
    };
    //通過構(gòu)建下載請(qǐng)求時(shí)獲得的downloadId進(jìn)行文件查詢
    DownloadManager.Query query = new DownloadManager.Query().setFilterById(downloadId);
    Cursor cursor = null;
    try {
      cursor = downloadManager.query(query);
      if (cursor != null && cursor.moveToFirst()) {
        //已經(jīng)下載文件大小
        bytesAndStatus[0] = cursor.getInt(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
        //下載文件的總大小
        bytesAndStatus[1] = cursor.getInt(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
        //下載狀態(tài)
        bytesAndStatus[2] = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
      }
    } finally {
      if (cursor != null) {
        cursor.close();
      }
    }
    return bytesAndStatus;
  }

private BroadcastReceiver downloadCompleteReceiver;
downloadCompleteReceiver = new BroadcastReceiver() {
      @Override
      public void onReceive(Context context, Intent intent) {
        //文件下載成功時(shí)
         DownloadManager.Query query = new DownloadManager.Query();
        //通過下載的id查找
        query.setFilterById(downloadId);
        Cursor c = downloadManager.query(query);
        if (c.moveToFirst()) {
            int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
            switch (status) {
              //下載完成
              case DownloadManager.STATUS_SUCCESSFUL:

                 break;

               }

         }
      }
    };
//注冊(cè)，這里只能攔截文件下載成功的廣播，并不能進(jìn)行進(jìn)度監(jiān)聽，在適當(dāng)?shù)牡胤饺∠嗛啅V播
context.registerReceiver(downloadCompleteReceiver,
        new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));

/**
 * 由于DownloadManager自身沒有提供實(shí)時(shí)進(jìn)度的api，所以通過以下定時(shí)器獲取已下載的文件大小
 */
  private void updateProgress() {
        //每隔0.5秒刷新一次進(jìn)度，在適當(dāng)?shù)牡胤接浀米N timeDisposable
        Disposable timeDisposable = Observable.interval(500, TimeUnit.MILLISECONDS).subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread()).subscribe(new DataConsumer<Long>() {
          @Override
          public void acceptData(@io.reactivex.annotations.NonNull Long aLong) {

            int [ ] bytesAndStatus = getBytesAndStatus(downloadId);
            //todo 在這里進(jìn)行回調(diào)即可
          }
        });

  }

 DownloadHelper.Builder builder = new DownloadHelper.Builder(this).title("下載通知")
          .description("正在下載新版本V1.2.0")
          .downloadUrl("http://download.sj.qq.com/upload/connAssitantDownload/upload/MobileAssistant_1.apk")
          .fileSaveName("MobileAssistant_1.apk").fileSavePath("testDownload")
          .notifyVisible(true)
          .fileType(DownloadHelper.FileType.APK).apkInstallHint(true).onProgressListener(new DownloadHelper.OnDownloadProgressListener() {
            @Override
            public void onProgress(int downloadedSize, int totalSize) {

              int progress =(int)((downloadedSize*1.0f/totalSize)*100);
              Logger.d("progress=%d",progress);
               //進(jìn)度回調(diào)

            }

            @Override
            public void onSuccess(Uri fileUri) {
             //文件下載成功回調(diào)的Uri
 

            }

            @Override
            public void onFail() {
             //文件下載失敗
  

            }

            @Override
            public void fileAlreadyExits(File file) { 
            //當(dāng)你想重復(fù)下載同樣的文件時(shí)，本地檢測(cè)是否存在同樣的文件，進(jìn)行回調(diào)
             
            }
          });
      DownloadHelper downloadHelper = builder.build();
      //開始下載
      downloadHelper.start();
      //移除下載任務(wù)
      downloadHelper.deleteDownloadFile();