title: Disable (positive) button of AlertDialog by Default
body: <p>How do you disable the positive button of an Android <code>AlertDialog</code> by <em>default</em>?</p>
  
  <p>It appears to be quite normal to want the positive button (In this case "Save") to be disabled before the user has made a change to the view (In this case an <code>EditText</code>.</p>
  
  <p>I know that I can get the button by calling <code>dialog.getButton(DialogInterface.BUTTON_POSITIVE)</code> but this call will return null if <code>show()</code> hasn't been called yet.</p>