Using a 9-patch is (sometimes) too much of a pain in the buttocks, when all you want is just a simple shadow, CSS has it, so why doesn't android??? Grrrrr...!
I found a hack.
While working on Mr.Query, I was looking for a built-in android icon because I was too lazy to design a new one.
Then, I stumbled upon:
I tried it on a few different layouts and buttons, and it's not bad!
Here are a few examples:
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