title: how to use OkHttp3 upload image?
body: <p>I have an image upload web service in node.js , it runs well , I can upload images by postman ,  and I try to take photo in android than upload it , node.js always reply</p>
  
  <blockquote>
    <p>'undefined'</p>
  </blockquote>
  
  <p>no error message , only the server show <strong>undefined</strong></p>
  
  <p>I use the same code as postman give me , but can't work , help please , stuck at upload for two days</p>
  
  <p>my code </p>
  
  <pre><code> imageUpload.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
  
                  Runnable r = new Runnable() {
                      @Override
                      public void run() {
                           final String boundary;
                          boundary = "===" + System.currentTimeMillis() + "===";
                          OkHttpClient client = new OkHttpClient();
                          File file = new File(imageLocation);
                          String fileName = file.getName();
                          MediaType mediaType = MediaType.parse("multipart/form-data; boundary=" + boundary);
  
                          RequestBody body = RequestBody.create(mediaType, boundary + "Content-Disposition: form-data; name=\\\"images\"; filename="+fileName+"\\\"\\r\\nContent-Type: image/jpeg\\\"\\r\\n\\r\\n\\r\\n" + boundary);
  
                          Request request = new Request.Builder()
                                  .url("http://localhost:3000/upload")
                                  .post(body)
                                  .addHeader("content-type", "multipart/form-data; boundary="+boundary)
                                  .addHeader("cache-control", "no-cache")
                                  .build();
                          try {
                              Response response = client.newCall(request).execute();
                          }catch (IOException e){
                              e.printStackTrace();
                          }
  
                      }
  
  
                   };
  </code></pre>
  
  <p>Postman code </p>
  
  <pre><code> OkHttpClient client = new OkHttpClient();
  
  MediaType mediaType = MediaType.parse("multipart/form-data; boundary=--   -011000010111000001101001");
  RequestBody body = RequestBody.create(mediaType, "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"images\";       filename=\"Costa Rican Frog.jpg\"\r\nContent-Type: image/jpeg\r\n\r\n\r\n-----011000010111000001101001--");
  Request request = new Request.Builder()
  .url("http://localhost:3000/upload")
  .post(body)
  .addHeader("content-type", "multipart/form-data; boundary=---011000010111000001101001")
  .addHeader("cache-control", "no-cache")
  .addHeader("postman-token", "e360f8ea-d179-fc78-6dff-c56791b7d9ba")
  .build();
  
  Response response = client.newCall(request).execute();
  </code></pre>