Once your basic Android application is up and running, the next interesting thing you can add to it is the capability to communicate with the outside world. You may want your application to send an SMS message to another phone when an event happens (such as when you reach a particular geographical location), or you may wish to access a Web service that provides certain services (such as currency exchange, weather, etc.).
In this chapter, you learn how to send and receive SMS messages programmatically from within your Android application.