Is there any sort of xml reference?
I found this which turned out to be invaluable for me
But I can’t figure out how I was supposed to know how to do that, had
I not found that post.
I know that the api reference has xml attributes listed for many of
the classes… but what about xml tags? Where is it documented that I
could build a shape using <padding>, <corners>, <solid> tags?
I’d really like to know where I can find such documentation.
The classes which have XML attributes, list them XML attributes in their own documentation. Attributes beginning with layout are documented in the containing layout class.
The manifest file is documented here. Google recently added a lot of new documentation, including documentation on XML resources. See this webpage on drawable resources.
There resources aren’t comprehensive, so R.styleable is still often the best bet. R.attr is better if you just want to see all attributes, rather than the attributes available for a particular tag.