User Interface Problems

[rgrant]

Sometimes new users have the freshest perspective on user interface problems.  Maybe we can put some Newbie proof-of-work posts to better use with constructive criticism of our ecosystem. I'll start by mentioning something that occurred to me today, a twice-sent transaction, sending a few bitcoins through Schildbach's Android "Bitcoin Wallet". 

I was trying to pay for my conference registration.  Seeing  "type address or name", I started to fill in the address name like a new phone book entry, figuring I'd scan the QR code to complete the entry.  But the send page is not this flexible.  It wants an address already in your book, and throws an error if you type something that it can't find in your contacts, when it's also not a valid address.  When I scanned the QR code, this apparently recursively brought up another sending page.  I sent coins.  I'm talking with Mike at the counter, and then I look at my screen again, and it's saying "Invalid Bitcoin Address".  This would not typically make sense, but maybe it's possible for a QR code to fail.  It looks exactly like the page I was working on before I sent, so I assume I've been thrown back to that.  I quickly scan the QR code and send again (oops).  At this point I forget whether I was again returned to the "Invalid Bitcoin Address".  I went and checked my transactions, which both confirmed soon afterwards.  The conference still owes me 3 BTC in return, as their payment processor (is it bitpay?) was unable to deal with a return on the spot.

And the moral is: don't allow reentrant send pages; or at least don't layer them on top of each other.  Android is partly at fault, for making the back button a free-for-all, instead of leaving threading backwards a visually pinned and high-level consequence of page creation, as Apple did.

[veox]

Good points. I would suggest contacting the software maintainers through other means, since they are unlikely to be scanning this forum for usability reports.

One more thing I've found useful is a unique identifier for each purchase. It doesn't have to be stored in any kind of history, and could be as simple as a date. So if you paid for "13:37:00" and then see a "13:36:30 failed" message, you wouldn't be repeating the payment. This is, of course, just an additional measure.