Building an Android Application

There's a track on Android Development, but if you use the program Android Studio to create your app you'll need to know Java very well, as well as learn XML (which is something that isn't offered through Treehouse yet). There's also Android development theory to understand too...like how the XML works with the Java to make your app, and the app development cycle (which is in the Android Development track at Treehouse).

So in other words, as far as I know, you need to learn multiple languages to make an app. Just like you need to know HTML, CSS, and Javascript to build a website. So XML and Java interact with each other to build the different elements you need to make a successful and dynamic application, and it's up to you to decide which you'd like to start with, Java or Android Development or exploring the web for XML.

The Android track assumes you've taken the Java track or have learned enough about Java elsewhere. I'd say the first two Java courses of the track are enough to get the first Android course or two, but you'd want the finish the Java track to take the later ones. The XML part you'll get from the Android courses anyway, and if you're familiar with HTML you should be able to pick if up without too much of a problem.