There is a known initialization issue which kicks in when leaving the app running in the background on low end devices. I am traveling this week, but have a fix which i will submit once properly tested. Sorry for the inconvenience.

Version 0.4.4b is out:

• The missing 'Copy to Clipboard' button in QR-code UI is now hopefully fixed. People who reported this please verify and post your results here
• Improved validation UI for Send activity. It is now very clear when the address or amount entered is invalid
• We now trim the send-to address. Got a report where an address with trailing space was pasted.
• The missing 'Copy to Clipboard' button in QR-code UI is now hopefully fixed. People who reported this please verify and post your results here

In progress:

• Bug fix: Initialization crash happening when app is resumed
• The much wanted address book

Enjoy

I can reproduce this now.
Root cause: On android devices apps may be resumed on any activity (screen) when they have been sent to the background. I knew that, but what I didn't know is that the app's process may be killed entirely and its resources reclaimed by the OS AND then the app may be resumed in any activity it was in before going into the background.

On low end devices this apparently happens all the time when you put the app into the background and start another app or two. I am pretty sure this is what you observe. Basically this means that the app needs to be able to re-initialize on any activity. I have a fix in mind, but it may take a week or two before I get it in. Please be patient.

I have tested BitcoinSpinner on several devices with Edge and 3g and for me it works flawlessly.
When you experience this can you for instance browse the web with your device?
Please use the 'report' option when the app crashes. This gives me a stack-trace of what went wrong, and I'll look into it.

There is a glitch in the ticker update. A fix is in the pipe which comes along with the QR code display fix. Until then you should get the right usd amount if you refresh after some time.

The problem is devices with small resolution. However, we have a solution now where a scrollbar is added if the resolution is small, which allows you to show display both large QR code and the button. The update is expected to go in tomotrrow.

The "cannot send less than 1 BTC" bug has been fixed is the latest update which also has a bunch of new features. More info in the Alternative Clients section.

Update 0.4.3b is now available

• Bug Fix: The bug where you could not spend less than 1 BTC is fixed
• BTC balance also shown as USD value: We automatically calculate the USD value using the current MtGox BTC buy price in USD
• Faster initialization: BitcoinSpinner no longer needs to initialize from scratch whenever you open it. If you click the Back button on the Main screen the app goes into the background
• Improved Transaction History: Unconfirmed transactions tell that they are unconfirmed, and transactions with less than 5 confirmations are displayed in a different color
• Improved QR code UI: The bug where some users experienced that the 'Copy to Clipboard' button was missing is fixed
• Added a donation button: If you click the Options button on the main screen there is a Donation option, which allows you to donate to our development effort and help paying the server bills. Please use it vigorously 

If you like BitcoinSpinner then please give it a good rating at the Android Marketplace.

Sounds like a good addition. I think the PIN should be optional, and something you can enable in Settings. If PIN is enabled you will get prompted for it whenever you:

• Send coins
• Make wallet backups
• Restore wallets on top of the existing one
• Export private keys

This way you can start the app and see your balance without entering a PIN

I am right now working on an address book, which I think most people are asking for (including myself  )
In the meantime, if you are nervous about people stealing your device you should PIN protect the entire device, which is generally a good idea.

Customers!

Really really cool!

Just tried importing a BitcoinSpinner private key with Blockchain.info. You have to use "Sipa Wallet Import Format" when importing on their site.

The format used is what Sirius implemented for the satoshi client, which is currently a patch you have to apply. I believe that the same format is used by pywallet.
The format is 1+32+4 bytes
1 byte: encodes the network (0x80 for production network)
32 bytes: private key
4 bytes: check sum, which is 4 first bytes of Sha256(byte 0 - 33)
The lot is then base-58 encoded

Source:
   /**
    * Get the private key as a base-58 encoded key.
    *
    * @param network
    *           The network parameters to use
    * @return The private key as a base-58 encoded key.
    */
   public String getBase58EncodedKey(Network network) {
      byte[] toEncode = new byte[1 + 32 + 4];
      // Set network
      toEncode[0] = network == Network.productionNetwork ? (byte) 0x80 : (byte) 0xEF;
      // Set key bytes
      byte[] keyBytes = getPrivateKeyBytes();
      System.arraycopy(keyBytes, 0, toEncode, 1, keyBytes.length);
      // Set checksum
      byte[] checkSum = HashUtils.doubleSha256(toEncode, 0, 1 + 32);
      System.arraycopy(checkSum, 0, toEncode, 1 + 32, 4);
      // Encode
      return Base58.encode(toEncode);
   }

Link to source: http://code.google.com/p/bccapi/source/browse/trunk/src/com/bccapi/core/PrivateECKeyExporter.java

Right. This is used with the Bitcoin address on the main page already. This allows you to easily share the textual representation of your Bitcoin address by clicking it and chose for instance send email. However, I don't think I can share a bitmap this way.


Yes. you can export your base-58 encoded private key (Option button, Settings -> Advanced -> Export private key) and import it using pywallet or the satoshi client with the import private key patch. This way you have the same private key in BitcoinSpinner and in your satoshi wallet. (There is no way to do an import the other way around.)

The solution might be to change this to a real activity instead of just a dialog, and add more options as you suggest. The problem with writing it to an SD card is that this would require the app to have more privileges, and I kind of like that it right now only needs Network access. This allows the user to have more trust that the app does not mess around with stuff it shouldn't, and prevents the user from by mistake leaving the image on the SD card for other apps to snag. Thanks for the suggestion, I'll have to think about this.

It may be caused by the resolution, but I doubt that as there seems to be room enough to render it. One of the problems with Android apps is that there are so many different versions and mods that it makes it hard to verify on all combinations. This is something I'll have to investigate.

It is a backup of a random seed that allows BitcoinSpinner to deterministically generate keys.


There is a 'Copy to Clipboard' button, which puts the textual representation of the seed on the clipboard. you can use this to regenerate the QR code using for instance http://qrcode.kaywa.com/

Personally I use a digital camera and take a picture, which i then print out. It's a bit cumbersome, but I haven't found a way to print directly from my phone.

Oops I broke the rule of three posts in a row.
Whenever you install BitcoinSpinner you should make a QR-code backup (Click Options button -> Settings -> Backup Wallet). This is a one time operation, which lets you restore the wallet at any time on any device. In short, killer-feature. I'll add a visual reminder which is shown right after first launch in a coming release.

Yep, that will be next monday. Read the rest of the thread for the embarrassing reason
To sum up, you cannot spend BTC if your balance is <= 1 BTC because of a UI bug that disables the Send button. I kneel in the dust, it is my fault sire.

BitcoinSpinner uses private app storage, which is wiped at uninstall. However, this also has the nice feature that other apps cannot get to it, which is paramount. Another nice thing is that BitcoinSpinner only needs network access privileges. This lets you know that it does not try to snag your address book or keys from other apps using SD card storage.