title: iphone/ipad: How exactly use NSAttributedString?
body: <p>Yes, many people are saying about Rich Text in iPhone/iPad and many knows about <code>NSAttributedString</code>. </p>
  
  <p>But how to use <code>NSAttributedString</code>? I searched for much time, no extract clues for this.</p>
  
  <p>I know how to set up a <code>NSAttributedString</code>, then what should I do to display a text on iPhone/iPad with rich text?</p>
  
  <p>The official docs says it should be used with <code>CoreText.Framework</code>, what does that mean?</p>
  
  <p>Is there any simple way like this?</p>
  
  <pre><code>NSAttributedString *str;
  .....
  UILabel *label;
  label.attributedString = str;
  </code></pre>