REST and Relaxation

Android does not have built-in SOAP or XML-RPC client APIs. However, it does have the Apache HttpClient library baked in. You can either layer a SOAP/XML-RPC layer atop this library or use it “straight” for accessing REST-style web services. For the purposes of this book, REST-style web services are considered simple HTTP requests for ordinary URLs over the full range of HTTP verbs, with formatted payloads (XML, JSON, etc.) as responses.

More expansive tutorials, FAQs, and HOWTOs can be found at the HttpClient web site (http://hc.apache.org/). Here, we'll cover the basics, while checking the weather.

HTTP Operations via Apache HttpClient

The first step to using HttpClient is, not surprisingly, to create an HttpClient object. The client object handles all HTTP requests on your behalf. Since HttpClient is an interface, you will need to actually instantiate some implementation of that interface, such as DefaultHttpClient.