title: android – show a button for a limited time
body: <p>I am making an app where an <code>ImageButton</code> is shown and fades until it disappears if the user doesn't touch it for too long.<br />
  I tried many different solutions (animation, <code>wait()</code>, etc.) but nothing did what I tried to...<br />
  It should work like a <code>Toast</code>, just show up for 3 seconds and then fade out (in the end of the process the visibility should be <code>GONE</code>.</p>