title: Android - Button with rotating/spinning 'loading' image when pressed
body: <p>I have a big 'Log in' button on my app. When the user taps this button, I want to replace the text with 'Logging in...', align it to the left instead of center and put a spinning circle on the right (but still inside the button). I'd like to use essentially the same button (but with different initial and loading text) in other places in my app.</p>
  
  <p>What's the neatest way to do this? For the actual spinning graphic, I was planning to use the <code>@drawable/spinner_white_16</code> that comes with Android.</p>
  
  <p>Thanks.</p>