title: How to create a custom toggle button with an image on it that also scales correctly for each density in android
body: <p>Here's what i'm trying to do:</p>
  
  <ul>
  <li>Create a toggle button.</li>
  <li>The toggle button's background color will be one color when on, one color when off.</li>
  <li>The toggle button will have an image centered over everything.</li>
  <li>The toggle button may have 3 on states, off, on, on, on, wherein each on state is for greater sensitivity for example and I may want
  to show that in the button some how.</li>
  <li>I'd like the button dimensions dialed in exactly for mdpi and have it scale for all other densities.</li>
  <li>I want the image centered on the button to stretch too using the appropriate density image of course.</li>
  </ul>
  
  <p>What would be the cleanest approach to do all of this, least number of headaches and most compatible for devices?  Is making the entire button background an image best? One for the on state and one for the off for each density.  Would using a button and overlaying an image onto it be a better approach and control the buttons background color property for the on/off states?  Maybe creating an XML in the "drawable" folder is an option.</p>