title: how to make a progress view like the one in KAYAK app
body: <p>I wonder how to make a progress view that looks like the one in KAYAK app (it's a travel app to search for flights and hotels), screenshot:</p>
  
  <p><img src="https://i.stack.imgur.com/58To4.png" alt="enter image description here"></p>
  
  <p>i dig into the resources of KAYAK app on a jailbroken iPhone and found the following 3 images that construct this progress view:</p>
  
  <p>progressbar-background@2x.png</p>
  
  <p><img src="https://i.stack.imgur.com/UoS0A.png" alt="enter image description here"></p>
  
  <p>progressbar-gradient@2x.png</p>
  
  <p><img src="https://i.stack.imgur.com/KgcoJ.png" alt="enter image description here"></p>
  
  <p>progressbar-overlay@2x.png</p>
  
  <p><img src="https://i.stack.imgur.com/KIwDO.png" alt="enter image description here"></p>
  
  <p>giving that the progress view has a moving overlay images that moves repeatedly along with the gradient image.</p>
  
  <p>any ideas or sample code would be highly appreciated.</p>