title: Flex: Update a label's text, which is a variable
body: <p>I have a label that get it's value from a var when you click on a button. The var has already been declared: </p>
  
  <pre><code>public function clickevent
  {
  label.text = aVariable; 
  }
  </code></pre>
  
  <p>Now I know that if i have a label like this: </p>
  
  <pre><code>&lt;s:Label id="label2" text="{aVariable}"/&gt; 
  </code></pre>
  
  <p>and aVariable is empty, label2's text is Null (it doesn't give an error, just "Null" in my situation). This is my current situation. </p>
  
  <p>What I'd like to know is when I later on change the aVariable's value to a string "hasChanged", for example. The label2's text should also change to "hasChanged" without the user having to push a button or anything to make this change. How can this be done?</p>