Android中Okhttp3实现上传多张图片同时传递参数

private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");/**   * 上传多张图片及参数   * @param reqUrl URL地址   * @param params 参数   * @param pic_key 上传图片的关键字   * @param paths 图片路径   */  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);        //遍历map中所有参数到builder        if (params != null){          for (String key : params.keySet()) {            multipartBodyBuilder.addFormDataPart(key, params.get(key));          }        }        //遍历paths中所有图片绝对路径到builder，并约定key如“upload”作为后台接受多张图片的key        if (files != null){          for (File file : files) {            multipartBodyBuilder.addFormDataPart(pic_key, file.getName(), RequestBody.create(MEDIA_TYPE_PNG, file));          }        }        //构建请求体        RequestBody requestBody = multipartBodyBuilder.build();        Request.Builder RequestBuilder = new Request.Builder();        RequestBuilder.url(reqUrl);// 添加URL地址        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();          }        });      }    });  } 

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);          }        });