title: iOS 7 status bar transparent
body: <p>In storyboard, in a view controller I tried add a navigation bar under the status bar, running it, it is transparent and shows a label that's supposed to be blurred, like by navigation bar.</p>
  
  <p><img src="https://i.stack.imgur.com/52dkE.jpg" alt="enter image description here"></p>
  
  <p>But when placing the same view controller embedded in a navigation view controller, the underneath background image could be blurred, which is my intention.</p>
  
  <p><img src="https://i.stack.imgur.com/ZwPrg.jpg" alt="enter image description here"></p>
  
  <p>What are these two way different results? What need to do for the firs method to make status bar blur?</p>
  
  <p>Thanks!</p>