It’s pretty easy to build APKs using Eclipse, but The Apache Ant project brings a few things to the table which you might be interested in—especially if you’re creating closed source apps. The package is designed to handle Java application builds (although it can be used with other languages as well). One of its best traits is that it will help shrink the size of your code by parsing for unused variables, methods, and classes to then strip them out as cruft. But I did mention closed source, and that’s because Ant has the ability to help obfuscate your bytecode to help prevent reverse-engineering through the use of ProGuard.
One of the reasons more people don’t use it is that it can be a little daunting at first glance. But to help you get a foothold, check out this setup guide for Ant builds. It’s not exactly tailor made, but if you search additional resources like the Ant Project Page itself, you should be able to get things working. The final project will spit out two builds at the touch of a button. One will be a private build for your own use during debugging. This code hasn’t been obfuscated, unlike the other package, which is a public copy that can be sent off to the Play Store or any other distribution channel of your choosing._________