HOW TO - Uploading image from android to rails server - multipart

I'm developing an Android app and I'm working on photo uploading to my rails server.

If I upload ad image from browser, server gives me this (I'm using paperclip gem to upload):

COMMIT CODE

[...] , "immagine"=>#
<ActionDispatch::Http::UploadedFile:0x103026dc8 @headers="Content-Disposition: form-data; name=\"segnalazione[immagine]\";
filename=\"24e14f4a46269f89ace12297b9ed4060aa3b44f5.jpeg\"\r\nContent-Type: image/jpeg\r\n", @content_type="image/jpeg", @tempfile=#<File:/var/folders/Ht/HtQoVYewE-i8RHpa2OY38U+++TI/-Tmp-/RackMultipart20110711-31693-p0wpzx-0>, 
@original_filename="24e14f4a46269f89ace12297b9ed4060aa3b44f5.jpeg">, 
[...]

My question is: how can I use multipart to upload correctly? On android, working with json objects I used:

HttpPost post = new HttpPost("http://10.0.2.2:3000/segnalaziones?format=json");
            JSONObject eventObj = new JSONObject();
            JSONObject holder = new JSONObject();

            try {
                // Genero l'oggetto JSON
                eventObj.put("categoria1", c1);
                eventObj.put("categoria2", c2);
                eventObj.put("categoria3", c3);
                eventObj.put("descrizione", descr);
                eventObj.put("dove", coord);
                eventObj.put("mood", mood);
                eventObj.put("via", via);
                //eventObj.put("android", android);
                holder.put("commit", "Spedisci");
                holder.put("segnalazione", eventObj);
                Log.e("Event JSON", "Event JSON = "+ holder.toString());
                StringEntity richiesta = new StringEntity(holder.toString());
                post.setEntity(richiesta);
                post.setHeader("Content-Type","application/json");

UPDATE

I've tried

HttpPost post = new HttpPost("http://10.0.2.2:3000/segnalaziones");

  MultipartEntity multipartEntity = new MultipartEntity(HttpMultipartMode.B开发者_开发百科ROWSER_COMPATIBLE);
  multipartEntity.addPart("commit", new StringBody("Spedisci"));

  multipartEntity.addPart("segnalazione[immagine]", new FileBody(photo)); 


post.setEntity(multipartEntity);  

HttpResponse response = client.execute(post);  

HttpEntity resEntity = response.getEntity();  
if (resEntity != null) {    
  resEntity.consumeContent();  
}

.. but in this case server receives well but doesn't "insert into".

Please look at the screens ... This screen is the post from browser ... all goes well

http://imageshack.us/photo/my-images/219/brozk.png/

This from android ... no "insert into" ... WHY??

http://imageshack.us/photo/my-images/13/andvv.png/

NOTE THAT if I send the same post without adding an image ... "INSERT INTO" works

here is a nice article link. This helped me to upload image from android device to server. I hope it will also help to you.