title: Notification Message/Alert Message and UICollectionView :
body: <p>I have a Navigation Bar, a Search Bar, and below, a Collection View.</p>
  
  <p><strong>My first question :</strong> 
  I'd like to have a custom notification bar (alert message ?) that would appear right below my Search Bar, over my Collection View, only the first time I launch my app, with the possibility for the user to close it, like so :</p>
  
  <p><img src="https://i.stack.imgur.com/8tCYG.png" alt="Notification Message/Bar appears over the Collection View"></p>
  
  <p>I tried to use UIAlertControllers but obviously it's not gonna make it.</p>
  
  <p><strong>My second question :</strong></p>
  
  <p>Also, how could I manage to get the same Notification Bar/Message, but, this time, instead of placing it over my Collection View, I am trying to find a way to push down my Collection View Cells as my Notification Bar appears (animation?) to create an effect like that :</p>
  
  <p><img src="https://i.stack.imgur.com/ezhH6.png" alt="Collection View pushed down by the Notification Message/Bar"></p>
  
  <p>Thank you very much for your help !</p>
  
  <p>Have a nice day,</p>
  
  <p>J.</p>