title: Center a drawable in a Button with background and no text
body: <p>I have a few buttons in my Android app. They each look kinda like this:</p>
  
  <pre><code>&lt;Button
      android:id="@+id/button_1"
      android:drawableTop="@drawable/an_icon"
      android:background="@drawable/a_background"
      android:layout_width="size_dp"
      android:layout_height="size_dp"&gt;
  &lt;/Button&gt;
  </code></pre>
  
  <p>Granted, I'm new to Android dev, but I can't figure out how to center the drawable in my button. I've tried the different drawableLocations, margins and padding for the button and its container, as well as drawablePadding, but I can't seem to get it done. Is there a way to center the drawable without abandoning Button for another View?</p>