title: How to prevent deleting a spannable in an EditText
body: <p>Is there a way to prevent a user from deleting or modifying a spannable in an EditText?  More specifically, I have an ImageSpan as the first character of the EditText.  I want to ensure the user cannot delete that ImageSpan.</p>
  
  <p>I realize I can use TextWatcher and replace the ImageSpan if the user deletes it.  That's rather ugly and I'm hoping there's a way to prevent the deletion in the first place.</p>
  
  <p>Here's a snip of code where I set the text value:</p>
  
  <pre><code>Bitmap bitmap = &lt;bitmap from elsewhere&gt;;
  String text = &lt;text to display after ImageSpan, from elsewhere&gt;;
  
  SpannableString ss = new SpannableString (" " + text);
  ImageSpan image = new ImageSpan (getContext(), bitmap, ImageSpan.ALIGN_BOTTOM);
  ss.setSpan (image, 0, 1, 0);
  
  setText (ss);
  </code></pre>