title: Let the user change font size
body: <p>in my dimens.xml I've:</p>
  
  <pre><code>&lt;dimen name="text_small"&gt;16sp&lt;/dimen&gt;
  &lt;dimen name="text_normal"&gt;18sp&lt;/dimen&gt;
  &lt;dimen name="text_medium"&gt;20sp&lt;/dimen&gt;
  &lt;dimen name="text_big"&gt;22sp&lt;/dimen&gt;
  </code></pre>
  
  <p>now I would like to let the user select the font size in a settings fragment. Let's say for example:</p>
  
  <ol>
  <li>Small   -2sp</li>
  <li>Normal  +0sp</li>
  <li>Medium  +2sp</li>
  <li>Big     +4sp</li>
  </ol>
  
  <p>So for example if the user select "Big" I would like that font size will be:</p>
  
  <pre><code>&lt;dimen name="text_small"&gt;20sp&lt;/dimen&gt;
  &lt;dimen name="text_normal"&gt;22sp&lt;/dimen&gt;
  &lt;dimen name="text_medium"&gt;24sp&lt;/dimen&gt;
  &lt;dimen name="text_big"&gt;26sp&lt;/dimen&gt;
  </code></pre>
  
  <p>Is there a way to do something like:</p>
  
  <p>Application Start:</p>
  
  <pre><code>if (sizeUser.equals("Big")) {
      text_small=24sp
  .....
  }
  </code></pre>
  
  <p>and so on?</p>