title: Transparent widget background?
body: <p>On Android widgets, how can I give the background a color, yet make is transparent at the same time? Please see the background on the clock at the screenshot. It's a black, yet transparent background. How can I do that on my own widget? Can I maybe also reference system colors, like the one on the screenshot from HTC Sense? Thanks for any hint!</p>
  
  <p><img src="https://i.stack.imgur.com/0JoUm.png" alt="enter image description here"></p>