This may be a dumb question but how to I build ODK Collect from
source? There is no build.xml file in the source tree (that I can
see)...
if you are using eclipse, install the android plugin, checking out the
project and you should be good to go. might be good to start with
hello world. http://developer.android.com/resources/tutorials/hello-world.html
if you aren't using eclipse, try
http://developer.android.com/guide/developing/projects/projects-cmdline.html
i'd recommend eclipse (not as software), but it does have good android tools...