title: How to change UIButton property
body: <pre><code>startButton.titleLabel.text = @"STOP";//do not work
  
  [startButton setTitle:@"STOP" forState:UIControlStateNormal];//works
  </code></pre>
  
  <p>Why does the first line of code not work when i use the dot syntax to change the property ? And which method is better for setting properties generally?</p>