title: Implementing a grid of buttons on iOS
body: <p>What would be the best way to implement a button layout similar to the following pictures?</p>
  
  <p>I was reading up on creating a custom UIView or UIControl, but then I started to think that maybe a custom UICollectionViewLayout would be better. I need to have the flexibility to make some of the buttons take up the space of two or more buttons (such as a larger button for the "equals" sign).</p>
  
  <p>I was thinking that NSMatrix would work great, but it's not implemented in iOS.</p>
  
  <p><strong>Can I get some advice on what would be the best way to approach this?</strong></p>
  
  <p>Thanks in advance!</p>
  
  <p><img src="https://i.stack.imgur.com/6dOui.jpg" alt="Calc Pro from Panoramic Software">
  <img src="https://i.stack.imgur.com/2MpzV.png" alt="Calculator HD Pro 1.7 from Cider Software"> <img src="https://i.stack.imgur.com/THocj.png" alt="Calculator HD Pro 1.7 from Cider Software"></p>