response.isSuccess == true but file not send

问题

I'm trying to upload a file from my app using Retrofit to a server. Everything is almost alright and the response.isSuccess equals true, but the file is not sent. I first present my code and then I mention some results that I have used for tracing the work flow.

public class MainActivity extends Activity 
{
    private static int RESULT_LOAD_VIDEO = 1;
    String decodableString;
    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final Button btn_load = (Button) findViewById(R.id.buttonLoadVideo);
        btn_load.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
               loadVideoFromGallery(btn_load);
            }
        });
    }
    /*
     * PICK THE VIDEO AND EXTRACT ITS ADDRESS
     */
    public void loadVideoFromGallery(View view) 
    {
        Intent galleryIntent = new Intent(Intent.ACTION_PICK,
                android.provider.MediaStore.Video.Media.EXTERNAL_CONTENT_URI);
        startActivityForResult(galleryIntent, RESULT_LOAD_VIDEO);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) 
    {
        super.onActivityResult(requestCode, resultCode, data);
        try {
            // When a video is picked
            if (requestCode == RESULT_LOAD_VIDEO && resultCode == RESULT_OK
                    && null != data) 
            {
                // Get the video from data
                Uri selectedVideo = data.getData();
                String[] filePathColumn = { MediaStore.Video.Media.DATA };
                Cursor cursor = getContentResolver().query(selectedVideo,
                        filePathColumn, null, null, null);
                cursor.moveToFirst();
                int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
                decodableString = cursor.getString(columnIndex);
                cursor.close();
                File file = new File(decodableString);
                Log.i("mok","done");
                upload(file);
            } else 
            {
                Toast.makeText(this, "You haven't picked any video",
                        Toast.LENGTH_LONG).show();
            }
        } catch (Exception e) 
        {
            e.printStackTrace();
            Toast.makeText(this, "Something went wrong", Toast.LENGTH_LONG)
                        .show();
            }
        }

    /*
     * UPLOAD THE SELECTED VIDEO TO THE SRVER
     */

    public void upload(File file)
    {
        final String BASE_URL = "http://192.168.1.7/";
        Retrofit retrofit = new Builder()
        .baseUrl(BASE_URL)
        .addConverterFactory(GsonConverterFactory.create())
        .build();

        Log.i("mok","here");//printed

        UploadApiService service = retrofit.create(UploadApiService.class);
        MediaType MEDIA_TYPE = MediaType.parse("video/mp4");
        RequestBody requestBody = RequestBody.create(MEDIA_TYPE, file);
        Call<ResponseBody> call = service.uploadVideo("desc", requestBody);
        call.enqueue(new Callback<ResponseBody>(){
            @Override
            public void onResponse(Response<ResponseBody> response, Retrofit retrofit) 
            {
                // TODO Auto-generated method stub
                if (response.isSuccess())
                {
                    Log.i("mok","S");//printed!
                    ResponseBody rb = response.body();
                }
                else
                {
                    Log.i("mok","F");
                    com.squareup.okhttp.ResponseBody rb = response.errorBody();
                }
            }
            @Override
            public void onFailure(Throwable t) 
            {
                t.printStackTrace();
                Log.i("mok",t.getCause()+"");
                Log.i("mok","T");
                finish();
            }
        });
    }
}

UploadApiService:

public interface UploadApiService 
{
    @Multipart
    @PUT("api/upload.php")
    Call<ResponseBody> uploadVideo(@Part("description") String description, @Part("video") RequestBody video);
}

upload.php:

<?php
ob_start();
var_dump($_FILES);
$result = ob_get_clean();
$file = fopen("test.html","w");
echo fwrite($file,$result);
fclose($file);

$uploaddir = '../uploads/';
$uploadfile = $_FILES['userfile']['name'];
$response = array();
if (move_uploaded_file($_FILES['userfile']['tmp_name'], $uploaddir.$uploadfile)) 
{
    $file = fopen("test1.txt","w");
    echo fwrite($file,"Hello World. Testing!");
    fclose($file);
    $response["username"] = $username;
    $response["result"] = "1";
    echo json_encode($response);
} else 
{
    $file = fopen("test2.txt","w");
    echo fwrite($file,"Hello World. Testing!");
    fclose($file);
    $response["result"] = "-1";
    echo json_encode($response);
}
?>

Trace:

In LogCat, "here" and "S" are printed and as a result of calling the php page, test.html is created(its result is mentioned below), test2.html is created as well. (No file uploaded)

content of test.html:

array (size=0)
empty

Note: The php page is working properly tested using an Html form.

来源：https://stackoverflow.com/questions/33720583/response-issuccess-true-but-file-not-send