How to realize stretching smoothly?
<p>I have a application in my mobile phone that is UC browser.there is a function that when i click the address bar,it will stretching smoothly.when i click the cancel,it will also.</p>

<p>i want to do this function,I use the scale to realize,but is not so good,not fluently.</p>

<p>could anybody tell me how to realize it?ths</p>

<p><img src="http://i.stack.imgur.com/Qzfzq.jpg" alt="enter image description here"></p>

<p>when i click the URL,it will stretching smoothly</p>

<p><img src="http://i.stack.imgur.com/xXZPR.jpg" alt="enter image description here"></p>
