Dunno if this is the intended process, but when you can something with zxing, it does copy it to the clipboard. hold press on the input field and select paste.

Also, I've seen some clients fumble with the bitcoin uri - by prepending or removing "bitcoin:" from the qr encoded text makes it work. I know you can't readily change someone else's QR code... just sayin... If that is the case, perhaps pasted it to an editable field, add/remove the protocol reference, and then drop it in your client address field.