You want to develop an Android application under Ubuntu: here's how to configure your environment.
It's easier to use an IDE: the usual choice is Eclipse. However, since 2013, Google provides a special version of IntelliJ, still in beta: Android Studio.
If you do not have installed Eclipse, you might as well install the Eclipse version with the development environment for Android provided by Google on the developer site.
Otherwise, to instal the latest Eclipse version (Luna) under Ubuntu 14.04, see the documentation d'Ubuntu-FR (in French). You only have to download the archive from Eclipse downloads.
Then you must instal the SDK and instal the Android plugin for Eclipse.
Check the correct API version is chosen, by right clicking on the project then Properties then Android and check the correct box.
Then, it's best to use version control system and to add the plugin for it to Eclipse. I used to use Subversion (SVN) but now, I got modern and I use Mercurial with a BitBucket depot (I prefer Mercurial to Git). To instal the MercurialEclipse plugin, just read the BitBucket documentation. Then configure Eclipse, by doing File → Import ... then choose Mercurial → Projects from Local Mercurial Repository (for an existing project).
For Mercurial, do not forget to configure your .hgignore file, to leave out of your version control the files not to be archived (i.e. the generated files, the gen, bin ... directories).
Happy Development ! !