Apps Encoding in uri.buider


Hello, i have a question about encoding of uri.builder.
I created an uri with uri.builder. the problem that one of my parameters values includes comma.

.appendQueryParameter("locatiion",-25.654, 45.98)

so builder replace comma with hex value(%2C). To repair this link, i wrote replace function.

But i want to use Encoding. here is my new url. But something wrong with it, i don't get results using it.
url = new Url(URLDecoder.decode(, "UTF-8"));

Thank you