Implement a download functionality using a button renderer

 I'm trying to implement a download functionality using a button renderer within a Grid, but I don't know how to make it work. Here is a part of my code:

@Override
public void click(RendererClickEvent event) 
{    
    final javax.xml.transform.stream.StreamSource source = new javax.xml.transform.stream.StreamSource(image_byte);
    final StreamSource streamSource = new StreamSource()
    {
          @Override
          public InputStream getStream()
          {       
               return source.getInputStream();
          }
   };
   StreamResource streamResource = new StreamResource(streamSource, nome_arquivo);
   FileDownloader fileDownloader = new FileDownloader(streamResource);
   fileDownloader.extend(event...);
}

I played around this subject a bit last spring and came up with GridFileDownloader add-on, but it's not exactly perfect and I haven't had time to work on it since. You might find some inspiration from the sources, though.

Did you try "DownloadStream" ?

final FileResource stream = new FileResource(new File("")) {
            @Override
            public DownloadStream getStream() {
                DownloadStream ds = null;
                
                // String filename = do sth;
                //some operation for ByteArrayInputStream
                //ByteArrayInputStream in = new ByteArrayInputStream(anyVal);
                //ds = new DownloadStream(in, "application/xml", filename);
                // Need a file download POPUP
                //ds.setParameter("Content-Disposition", "attachment; filename=" + filename);

                return ds;
            }
        };
        UI.get().getPage().open(stream, stream.getFilename(), true);