Examples of how to download files with RxJava2.x and ReTrofit2.x multi-threads

This article mainly introduces the sample code of RxJava2.x+ReTrofit2.x multi-threaded download file, which has certain reference value. Those who are interested can learn about it

Written in front:

Received a request from the company: To make an apk upgrade function, the principle is actually very simple. Baidu also has a lot of examples, but most of them use frameworks or HttpURLConnection. I really don’t want to do this. . I just watched RxJava2.x+ReTrofit2.x for two days. It is said that these two frameworks are currently the most popular asynchronous request frameworks. This article uses RxJava2.x+ReTrofit2.x to implement the function of multi-threaded file downloading.
If you don’t know much about RxJava2.x+ReTrofit2.x, please read the relevant documents first.
Master, please ignore this.

Idea analysis:

The idea is concise and clear, mainly divided into the following four steps

1. Get the server file size.
2 .Plan the number of threads according to the file size.
3. Combine the downloaded content into a complete file.
4. Call the installation and install the apk.
Function implementation

, next is your final Favorite code link

1. First look at the reference

  compile 'io.reactivex:rxjava:latest.release'
  compile 'io.reactivex:rxandroid:latest.release'
  //network - squareup
  compile 'com.squareup.retrofit2:retrofit:latest.release'
  compile 'com.squareup.retrofit2:adapter-rxjava:latest.release'
  compile 'com.squareup.okhttp3:okhttp:latest.release'
  compile 'com.squareup.okhttp3:logging-interceptor:latest.release'

2. Construct a download interface DownloadService.class

public interface DownloadService {
  @Streaming
  @GET
  //downParam下载参数，传下载区间使用
  //url 下载链接
  Observable<ResponseBody> download(@Header("RANGE") String downParam,@Url String url);
}

3. For ease of use, a RetrofitHelper.class is encapsulated, mainly used for:

a) Instantiate OkHttpClient and Retrofit.

  public RetrofitHelper(String url, DownloadProgressListener listener) {

    DownloadProgressInterceptor interceptor = new DownloadProgressInterceptor(listener);

    OkHttpClient client = new OkHttpClient.Builder()
        .addInterceptor(interceptor)
        .retryOnConnectionFailure(true)
        .connectTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
        .build();
    retrofit = new Retrofit.Builder()
        .baseUrl(url)
        .client(client)
        .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
        .build();
  }

b) Encapsulation download method. I used three download threads for this download, and there is no dynamic allocation. You can dynamically allocate the number of threads according to your own needs

 public Observable download(@NonNull final long start, @NonNull final long end, @NonNull final String url, final File file, final Subscriber subscriber) {
    String str = "";
    if (end == -1) {
      str = "";
    } else {
      str = end + "";
    }
    return retrofit.create(DownloadService.class).download("bytes=" + start + "-" + str, url).subscribeOn(Schedulers.io()).unsubscribeOn(Schedulers.io()).map(new Func1<ResponseBody, ResponseBody>() {
      @Override
      public ResponseBody call(ResponseBody responseBody) {
        return responseBody;
      }
    }).observeOn(Schedulers.computation()).doOnNext(new Action1<ResponseBody>() {
      @Override
      public void call(ResponseBody responseBody) {
        //第一次请求全部文件长度
        if (end == -1) {
          try {
            RandomAccessFile randomFile = new RandomAccessFile(file, "rw");
            randomFile.setLength(responseBody.contentLength());
            long one = responseBody.contentLength() / 3;
            download(0, one, url, file, subscriber).mergeWith(download(one, one * 2, url, file, subscriber)).mergeWith(download(one * 2, responseBody.contentLength(), url, file, subscriber)).subscribe(subscriber);

          } catch (IOException e) {
            e.printStackTrace();
          }
        } else {
          FileUtils fileUtils = new FileUtils();
          fileUtils.writeFile(start, end, responseBody.byteStream(), file);
        }

      }
    }).subscribeOn(AndroidSchedulers.mainThread());
  }

4. Call download

Note: Call download is performed in MainAcitivity. For the sake of intuition, we encapsulate the progress interceptor to facilitate the progress display, but this article will not describe the implementation process of the progress interceptor, such as You can leave a message if necessary.

a) Implement the listening object

subscriber = new Subscriber() {
      @Override
      public void onCompleted() {
        Log.e("MainActivity", "onCompleted下下载完成");
//        Toast.makeText(MainActivity.this, "onCompleted下下载完成", Toast.LENGTH_LONG).show();
        installAPK("mnt/sdcard/aaaaaaaaa.apk");
      }

      @Override
      public void onError(Throwable e) {
        e.printStackTrace();
        Log.e("MainActivity", "onError: " + e.getMessage());
      }

      @Override
      public void onNext(Object o) {

      }
    };

b) Call the encapsulated RetrofitHelper to implement the download

 RetrofitHelper RetrofitHelper = new RetrofitHelper("http://gdown.baidu.com/data/wisegame/0904344dee4a2d92/", new DownloadProgressListener() {
      @Override
      public void update(long bytesRead, long contentLength, boolean done) {

        SharedPF.getSharder().setLong("update", bytesRead);
        pro.setProgress((int) ((double) bytesRead / contentLength * 100));
        temp++;
        if (temp <= 1) {
          Log.e("MainActivity", "update" + bytesRead + "");
        }
      }
    });
    RetrofitHelper.download(0, -1, "QQ_718.apk", new File("mnt/sdcard/", "aaaaaaaaa.apk"), subscriber).subscribe(new Subscriber() {
      @Override
      public void onCompleted() {

      }

      @Override
      public void onError(Throwable e) {

      }

      @Override
      public void onNext(Object o) {

      }
    });

  }

Note: Finally post an apk installation method

  // 安装APK
  public void installAPK(String filePath) {
    Intent intent = new Intent();
    intent.setAction("android.intent.action.VIEW");
    intent.addCategory("android.intent.category.DEFAULT");
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);// 广播里面操作需要加上这句，存在于一个独立的栈里
    intent.setDataAndType(Uri.fromFile(new File(filePath)), "application/vnd.android.package-archive");
    mainActivity.startActivity(intent);
  }

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