Android: Retrofit 2 multiple file upload howto?

Question

Uploading a single image seems to be no problem with retrofit 2.

However, i cant figure out how to upload 2 images at the same time.

if followed the documentation: http://square.github.io/retrofit/2.x/retrofit/retrofit2/http/PartMap.html

File file = new File(path, "theimage");
File file2 = new File(path2, "theimage");
RequestBody requestBody = RequestBody.create(MediaType.parse("image/png"), file);
RequestBody requestBody2 = RequestBody.create(MediaType.parse("image/png"), file2);
Map<String, RequestBody> params = new HashMap<>();
params.put("image2", requestBody2 );

Call<ResponseBody> call = service.upload(requestBody, params);
call.enqueue(new Callback<ResponseBody>() {
@Override
public void onResponse(Response<ResponseBody> response, Retrofit retrofit) {
    Log.v("Upload", "success");
}

interface:

public interface FileUploadService {

    @Multipart
    @POST("/upload")
    Call<ResponseBody> upload(
        //@Part("image_logo\"; filename=\"image.png\" ") RequestBody file,
        @Part("file") RequestBody file,
        @PartMap Map<String, RequestBody> params
     //  @Part("description") String description
);

this gives a 'Upload: success' but on the server side i get gibberish:

CONTENT_TYPE: multipart/form-data; boundary=50fbfeb3-3abc-4f15-b130-cdcb7e3a0e4f

CONTENT POST:Array ( [file] => �PNG IHDR L alotofbinarygibberish.... ... snip [file2] => �PNG IHDR L more binary gibberish...

can anyone point me in the right direction?

single upload does work so thats not the problem, i'm trying to upload 2 or more images.

---

if i change it to this:

HashMap<String, RequestBody> partMap = new HashMap<String, RequestBody>();
partMap.put("file\"; filename=\"" + file.getName(), requestBody);
partMap.put("file\"; filename=\"" + file2.getName(), requestBody);
Call<ResponseBody> call = service.upload(partMap);

---

@Multipart
@POST("/upload")
Call<ResponseBody> upload(
    @PartMap() Map<String, RequestBody> partMap,

---

i get no gibberish but only the second image is uploaded... !?

---

UPDATE

i tried this Retrofit(2.0 beta2) Multipart file upload doesn't work solution but get an error that @body can not me used with multipart: Java.lang.IllegalArgumentException: @Body parameters cannot be used with form or multi-part encoding. (parameter #1)

        for (String key : keys) {
            Bitmap bm = selectedImages.get(key);
            File f = new File(saveToInternalStorage(bm, key), key);
            if (f.exists()) {
                buildernew.addFormDataPart(key, key + ".png", RequestBody.create(MEDIA_TYPE, f));
            }
        }
        RequestBody requestBody = buildernew.build();

-

Call<ResponseBody> upload(
    @Body RequestBody requestBody

Answer 1

---

This works:

            final MediaType MEDIA_TYPE=MediaType.parse("image/png");
            HashMap<String,RequestBody> map=new HashMap<>(selectedImages.size());
            RequestBody file=null;
            File f=null;
            Set<String> keys = selectedImages.keySet();
            for (String key : keys) {
                try {
                    Bitmap bitmap = selectedImages.get(key);
                    f = new File(saveToInternalStorage(bitmap, key), key);

                    FileOutputStream fos = new FileOutputStream(f);
                    if(bitmap!=null){
                        bitmap.compress(Bitmap.CompressFormat.PNG, 0 , fos);
                        fos.flush();
                        fos.close();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                    return;
                }

                file=RequestBody.create(MEDIA_TYPE, f);
                map.put(""+key+"\"; filename=\""+key+".jpg",file);
                Log.i("##MYLOG###", "### MAP PUT:" + key + " filename:"+key+".jpg file:" + file.toString() +" type:"+ file.contentType() );
                file=null;
                f = null;
            }

--

Call<ResponseBody> upload(
        @PartMap() Map<String,RequestBody> mapFileAndName //for sending multiple images

--

beware: while debugging this with the httpClient.interceptors() i saw only a single upload but when checking the endpoint itself to see what it actually got, it DID get the multiple uploads!