Retrofit 2 Multipart POST request sends extra quotes to PHP

Use RequestBody for all your parameters. Please go through below code!!

File file = new File(imagePath);
RequestBody requestBody = RequestBody.create(MediaType.parse("multipart/form-data"), file);
MultipartBody.Part imageFileBody = MultipartBody.Part.createFormData("media", file.getName(), requestBody);
RequestBody id = RequestBody.create(MediaType.parse("text/plain"),addOfferRequest.getCar_id());
ApiCallback.MyCall<BaseResponse> myCall = apiRequest.editOfferImage(imageFileBody,id);

---

Use RequestBody class of Retrofit instead of String

@Multipart
@POST(ApiURL)
ApiCallback.MyCall<BaseResponse> editOfferImage(@Part MultipartBody.Part imageFile,@Part("id") RequestBody id);

For your issue, please use as the documentation

Scalars (primitives, boxed, and String): com.squareup.retrofit2:converter-scalars

So, add compile 'com.squareup.retrofit2:converter-scalars:2.0.1' into build.gradle file

Then...

Retrofit retrofit = new Retrofit.Builder()
    .baseUrl(API_URL_BASE)
    .addConverterFactory(ScalarsConverterFactory.create())
    //.addConverterFactory(GsonConverterFactory.create())
    .build();

Hope it helps!

I faced this on my project today and this is how I solved it. I changed @Part on my string and other primitive values to @Query, and for file (in my case image) i used @Part. Looks like @Query treats strings in a different way compared to @Part.

So my answer to original question would look like this:

@Multipart
@POST("api.php")
Call<ResponseBody> doAPI(
  @Query("lang") String lang,
  @Part("file\"; filename=\"image.jpg") RequestBody file
);

This should send string values without unwanted quotes. Sadly, I cant explain why this works, it has something to do with @Part encoding of data.