title: searchBarTextDidBeginEditing delegate method called again on back button click
body: <p>I am developing iPhone app in which i  got stuck at one point.</p>
  
  <p>I have one viewController with navigation bar hidden and search bar is in the centre of the page.</p>
  
  <p>when user clicks on searchBar <code>searchBarTextDidBeginEditing</code> method gets fired. </p>
  
  <p>after this on text change of searchBar <code>textDidChange</code> method i am loading live data in tableview and on click of tableview i am navigating to other page with navigation bar non hidden.</p>
  
  <p>Now when i press back button again i comes to search page here <code>searchBarTextDidBeginEditing</code> method again gets fired.</p>
  
  <p>Why this method gets called again on back press ?</p>
  
  <p><strong>Please help and thanks in advance.</strong></p>