title: close an activity after some time
body: <p>I'm trying to make a dice rolling app and I want to run an activity which displays an image of the result when a button is pressed and close it after a few seconds. So how can I do this?</p>
  
  <p>Maybe there's another way to display an image on top of my activity without calling a new activity? I'm not sure.</p>
  
  <p>I've read some things about timers but I don't really get it. And I know people will tell me to let the user tap to dismiss the window but for this app I'm sure I want it gone automatically.</p>