Where did you get that site URL from? Bitcoinj is hosted at http://code.google.com/p/bitcoinj/

In the links section, you'll see a discussion group.

I've never used the SeedPeers class. I'd check manually if these IP addresses are still online. As I wrote earlier, perhaps the list of peers needs to be updated in bitcoinj.

Thanks, Mike.

Yes, Bitcoin Wallet is aimed mainly at non-technical people. Concepts like "synching" does not make any sense to them, so I want to remove them from the UI entirely.

If you are a power user and want full control, I suggest building your own version. It's open source.

I'd love to see someone broadcasting the blockchain on a wavelength that goes around the globe. Devices with a radio might be able to receive and decode those, even in remote areas without cell coverage. Well, just dreaming...

The Bluetooth channel will currently not be set up again.

However, you're right that you could also use the "transaction QR code" feature to submit a transaction. You can also use NFC. The problem with that is that QR codes are limited in size, so some transactions will not fit.

If this turns out to be a real problem, we can work on the bitcoinj default coin selector to not build transactions exceeding a given byte size.

Why don't you just try it out? I'd be interested in real feedback.

In theory, this should be possible.

In practise, the current implementation is not designed for 100% robustness. If the Bluetooth submission fails for some reason, you'll need to connect to regular Bitcoin peers to get the tx through.

I assume SeedPeers only has mainnet peers. Whereas if you build the app from master, you are running on testnet.

The issue with paper wallets is you need to query the blockchain for finding the unspent outputs. Bitcoin Wallet (as a true SPV client) does not have a blockchain at hand. It would need to rely on external services.

If however someone would design an extended paper wallet format which includes the unspent outputs in the QR code, it would be possible to sweep that (only entirely, not partially).

First of all, Bitcoin Wallet does not use WalletAppKit. So your first change should not have any effect.

Second, did you build Bitcoin Wallet for testnet or mainnet? I assume SeedPeers only has mainnet peers, and who knows if they're still online. I'm not sure if they've ever been updated.

Well, the report feature can report up to 7 days worth of logs. So if you know the exact date it might be worth to report nevertheless.

All locations of files are documented in this readme:

http://bitcoin-wallet.googlecode.com/git/wallet/README

Would you like to send me your logs so I can look up exactly what consumed your battery? Use Options > Settings > Report issue. Please refer to this post in the description.

It does not yet send a chain of transactions, if that's what you're aiming for. This is planned, but bitcoinj does not offer the API yet.

So yes, the second merchant will throw away your transaction if it builds on your first transaction and he doesn't know about it. It will all sort out later when parties get online and (re-)broadcast their pending transactions.

However, in reality your wallet should be fragmented enough that pending transactions don't build on each other.

If anyone has got a spare S2 device (which hopefully got replaced by a shiny Nexus phone), it would make a great donation! These TouchWiz devices have a lot of device dependent quirks unfortunately... )-:

Sounds like a  bug. Is it reproducable?


All app-provided buttons use the internal barcode scanner. What phone do you use? There is a known issue with the Galaxy S2 that autofocus does not work but I don't know why. I don't have non-nexus phones to test with.

One more thought: The new offline transaction feature would have helped in this case - right? The only caveat is that currently, the feature does not transmit chains of transactions - only the transaction itself.

Although I only saw the result and not his actions, that sounds right. At least I had that happening to my wallet as well. It was never much of a problem, because my wallet is always fragmented enough so I can easily find another output to spend for my beer. But I agree it can be a problem for big transactions.


Bitcoinj would trigger this internally, right?


Please do. The sooner we have this the better. We realized already a year ago how much this would simplify the interaction. An ack message would also be useful, by the way.

Thanks, fixed.

A screenshot would help.

Ok, let's see how it works out. It is just from my experience with web browsers which do lazy-load the missing intermediate parts in certificate chains. But anyway, the significance of a X.509 certificate is negliable, as users have no chance of getting their trust store right.


I think the right way is skip the intermediate step and send a payment request right away. For NFC, this is pretty straightforward. Put the BIP70 formatted request onto the tag with the appropriate BIP71 MIME type. For QR, I'd suggest Base43-encode the request and put it into a bitcoin: uri (perhaps gzip compress it first) - just like it is done with transactions already. We can skip the signature because we're meeting the person f2f already, so the QR should stay small enough to be scanned easily.

Edit: I just thought that PaymentDetails/payment_url should be a list 0..x of urls. How should the merchant know the capabilities of the customer? He should provide all alternatives he can handle.
Edit 2: On #bitcoin-dev, the consensus seems to be dedicated fields for each medium of communication rather than a list of generic uris.