使用具有暂停和恢复功能的http POST方法上传图像或文件

Question

我正在尝试使用okhttp3实现暂停和恢复功能以在android中上传文件。要上传的文件将转换为块然后上传每个块。当网络出现错误时，应用程序必须尝试上传剩余的从那里停下来的块。这是我一直在使用的自定义请求主体

class ProgressRequestBody extends RequestBody{

public ProgressRequestBody(final File mfile, final UploadCallbacks listener) {
    this.mfile = mfile;
    this.mListener = listener;
}

private File mfile;
private String mpath;
private UploadCallbacks mListener;

private static final int DEFAULT_BUFFER_SIZE = 2048;

public interface UploadCallbacks{
    void onProgressUpdate(int percentage);
    void onError();
    void onFinished();


}


@Override
public long contentLength() throws IOException {
    return mfile.length();
}

@Nullable
@Override
public MediaType contentType() {

    return MediaType.parse("image/*");
}

@Override
public void writeTo(BufferedSink sink) throws IOException {
    long fileLength = mfile.length();
    byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
    FileInputStream fileInputStream = new FileInputStream(mfile);
    long uploaded = 0;
    try{

        int read;
        Handler handler = new Handler(Looper.getMainLooper());
        while((read = fileInputStream.read(buffer)) != -1)
        {
            handler.post(new ProgressUpdater(uploaded,fileLength));
            uploaded += read;
            sink.write(buffer,0,read);
        }

    }
    finally {
        fileInputStream.close();
    }

}

这是用于上传功能的代码

 ProgressRequestBody fileBody = new  ProgressRequestBody(file,this);
MultipartBody.Part filePart = MultipartBody.Part.createFormData("datafile",file.getName(),fileBody);

apiInterface = APIClient.getClient().create(ApiInterface.class);
Call<SuccessResponse> call = apiInterface.uploadImage(filePart);
call.enqueue(new Callback<SuccessResponse>() {....}