下載進度的在之前的文章中實現(xiàn)過：
Android的Splash啟動圖的兩種動態(tài)切換方式

根據(jù)服務(wù)器的數(shù)據(jù)聲明上傳文件的方法

    @Multipart
    @POST("upload")
    Observable<UploadImgBean> uploadHeadPic(@Part MultipartBody.Part files);

借助okhttp的RequestBody我們構(gòu)造一個FileRequestBody繼承RequestBody

public class FileRequestBody extends RequestBody {
    private RequestBody mRequestBody;
    private LoadingListener mLoadingListener;
    private long mContentLength;

    public FileRequestBody(RequestBody requestBody, LoadingListener loadingListener) {
        mRequestBody = requestBody;
        mLoadingListener = loadingListener;
    }

    //文件的總長度
    @Override
    public long contentLength() {
        try {
            if (mContentLength == 0)
                mContentLength = mRequestBody.contentLength();
            return mContentLength;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return -1;
    }

    @Override
    public MediaType contentType() {
        return mRequestBody.contentType();
    }

    @Override
    public void writeTo(BufferedSink sink) throws IOException {
        ByteSink byteSink = new ByteSink(sink);
        BufferedSink mBufferedSink = Okio.buffer(byteSink);
        mRequestBody.writeTo(mBufferedSink);
        mBufferedSink.flush();
    }


    private final class ByteSink extends ForwardingSink {
        //已經(jīng)上傳的長度
        private long mByteLength = 0L;

        ByteSink(Sink delegate) {
            super(delegate);
        }

        @Override
        public void write(Buffer source, long byteCount) throws IOException {
            super.write(source, byteCount);
            mByteLength += byteCount;
            mLoadingListener.onProgress(mByteLength, contentLength());
        }
    }

    public interface LoadingListener {
        void onProgress(long currentLength, long contentLength);
    }
}

實現(xiàn)上傳

RequestBody requestFile =
                RequestBody.create(MediaType.parse("multipart/form-data"), file);
        FileRequestBody fileRequestBody = new FileRequestBody(requestFile, new FileRequestBody.LoadingListener() {
            @Override
            public void onProgress(long currentLength, long contentLength) {
                //獲取上傳的比例
                Log.d("Tag---", currentLength + "/" + contentLength);
            }
        });
        //files是與服務(wù)器對應(yīng)的key
        MultipartBody.Part body =
                MultipartBody.Part.createFormData("files", file.getName(), fileRequestBody);
        RetrofitHelper.userApi().uploadHeadPic(body).subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Action1<UploadImgBean>() {
                    @Override
                    public void call(UploadImgBean uploadImgBean) {
                        //上傳成功
                    }
                }, new Action1<Throwable>() {
                    @Override
                    public void call(Throwable throwable) {
                       //上傳失敗
                    }
                });