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As you ve seen in this chapter, there s a bewildering range of technologies available for wireless messaging. The current version of MediaGrabber works fine, so long as the user has a compatible email account, but you could expand it to provide even more features to your users. Attach a MessageListener to your outgoing email. When the message status is updated, check to see whether it was sent successfully or if there was an error. Report the final message status to the user. Be sure to remove the MessageListener when the SendingScreen is dismissed. If your device and plan support it, try sending MMS messages instead of email. Listen for incoming email messages. If the message contains one of the strings our app uses (like Here s some sound! ), notify the user that a friend has sent them a MediaGrabber file. You can decide whether to add these new capabilities to the existing SendingScreen, or create new classes to handle those expanded functions. You can also polish the presentation by allowing people to enter their own custom messages on outgoing media.

This chapter has shown the many wireless messaging choices that you can use when developing an app. Each option has its own unique profile and advantages, so there is no one-size-fits-all solution. Depending on your app s needs, you may be drawn to the ubiquity of SMS, the presentation options of MMS, the desktop integration and wide capacity of email, or the unique BlackBerry aspect of PIN messaging. Each has its own quirks, and now that you are aware of them, you will be able to take full advantage of each to its fullest. Many successful BlackBerry apps will stick with conventional networking technologies, such as HTTP or socket programming. Those are great choices if you want to reuse existing server components, run on any device with a data connection, or require more continuous communication. Wireless messaging, on the other hand, is perfect for connecting with existing platforms of message delivery with very little extra effort on your part. Decide early in your project which is the best approach. Your app is now capturing information on the device and sending it over the network. Wouldn t it be bad, though, if your boss ended up seeing the pictures you took at that wild party 5 will examine ways to protect the data we send from the device, keeping it secure and making sure that the intended recipient has access.

Next to their email capabilities, BlackBerry devices are probably most famous for their security. Corporations love them because data sent over a BlackBerry Enterprise Server is automatically encrypted, because they can remotely wipe stolen devices, and because of their integration with corporate security policies. With this strong legacy, many BlackBerry users are naturally interested in the strength of security offered by applications they run. Cryptography is a broad topic that can and does fill many books. This chapter focuses on some of the tools available to an application developer like you when writing for the BlackBerry platform. We will look at some of the most common goals when writing secure apps, and the various APIs you can use to implement those goals. Keep in mind that security is a serious, multi-faceted issue. You should view this chapter's contents as a useful starting point that will continue with further education, security audits, and real-world testing.

Suppose that you write a business expense-tracking app. This app allows users to enter their receipts onto the BlackBerry, then uploads the data to a server or sends the user an email. So far, so good. Now, imagine that while the app is transmitting that data, a hacker uses a packet sniffer to observe the message being sent. Now, someone else has access to personal financial information from your users, which they may use to steal their identity or crack bank accounts. To be sure, not every app will need to worry about this sort of thing. Who cares if a hacker eavesdrops on a weather-predicting app Early on in development, you should consider and discuss the security profile of your app. 1. 2. 3. Does the app have access to sensitive data Does the app store such data Transmit it What are the risks associated with loss or interception of that data