Okhttp3 in Android realizes uploading multiple pictures and transferring parameters at the same time

Before uploading pictures, they were directly converted into io and transmitted to the server, instead of using the frame to transmit pictures.

Recently, I have done a project and plan to upload pictures in a different way.

With the development of Android, Okhttp is becoming more and more important, so this time I chose Okhttp to upload pictures.

Okhttp has been updated to Okhttp 3, and there are some differences in usage compared with before. I found a lot of information on the Internet,

And with java background colleagues repeatedly debugging, finally successfully upload a number of pictures, and at the same time pass some key-value pairs of parameters.

Here's my encapsulation of the process:

private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");

/**
   *  Upload multiple pictures and parameters 
   * @param reqUrl URL Address 
   * @param params  Parameter 
   * @param pic_key  Keywords for uploading pictures 
   * @param paths  Picture path 
   */
  public Observable<String> sendMultipart(String reqUrl,Map<String, String> params,String pic_key, List<File> files){
    return Observable.create(new Observable.OnSubscribe<String>(){

      @Override
      public void call(Subscriber<? super String> subscriber) {
        MultipartBody.Builder multipartBodyBuilder = new MultipartBody.Builder();
        multipartBodyBuilder.setType(MultipartBody.FORM);
        // Traversal map All parameters in the builder
        if (params != null){
          for (String key : params.keySet()) {
            multipartBodyBuilder.addFormDataPart(key, params.get(key));
          }
        }
        // Traversal paths The absolute path of all pictures in the builder , and agreed that key Such as " upload "Accepting multiple pictures in the background key
        if (files != null){
          for (File file : files) {
            multipartBodyBuilder.addFormDataPart(pic_key, file.getName(), RequestBody.create(MEDIA_TYPE_PNG, file));
          }
        }
        // Build the request body 
        RequestBody requestBody = multipartBodyBuilder.build();

        Request.Builder RequestBuilder = new Request.Builder();
        RequestBuilder.url(reqUrl);//  Add URL Address 
        RequestBuilder.post(requestBody);
        Request request = RequestBuilder.build();
        mOkHttpClient.newCall(request).enqueue(new Callback() {
          @Override
          public void onFailure(Call call, IOException e) {
            subscriber.onError(e);
            subscriber.onCompleted();
            call.cancel();
          }

          @Override
          public void onResponse(Call call, Response response) throws IOException {
            String str = response.body().string();
            subscriber.onNext(str);
            subscriber.onCompleted();
            call.cancel();
          }
        });
      }
    });
  } 

Call in UI interface:

OkHttp3Utils.getInstance().sendMultipart(Constants.URL.URL_ADD_NOTICE, mMap, "appendix", mImageList)
        .observeOn(AndroidSchedulers.mainThread())
        .subscribeOn(Schedulers.newThread())
        .subscribe(new Subscriber<String>() {
          @Override
          public void onCompleted() {

          }

          @Override
          public void onError(Throwable throwable) {
            LogUtil.i(TAG, "throwable:" + throwable.toString());
          }

          @Override
          public void onNext(String s) {
            
            LogUtil.i(TAG, "s:" + s);
          }
        }); 

During debugging, multipartBodyBuilder. addFormDataPart (pic_key, file. getName (), RequestBody. create (MEDIA_TYPE_PNG, file); It is written as multipartBodyBuilder.addFormDataPart (pic_key, null, RequestBody.create (MEDIA_TYPE_PNG, file); As a result, the background can't get pictures in the conventional way (although the picture data can be seen when debugging breakpoints), which needs attention.