How to change UICollectionViewCell size programmatically in Swift?

Question

I have a UICollectionView with a segmented control to switch between data. But how do I change the UICollectionViewCell size properties programmatically ? then I can custom each style appropriately for each data type.

For example change the width to 520 points and height to 100. I am new to iOS development and am experienced with CSS :/

I know how to do it in Xcode (obviously) but do not know the correct methods to change it in swift. Any ideas or feedback is much appreciated (Y)

Answer 1

Make sure you conform to UICollectionViewDelegateFlowLayout for your class (for swift4)

eg. class MyClass: UICollectionViewDelegateFlowLayout 

Prior to Swift 3

//Use for size func collectionView(collectionView: UICollectionView,         layout collectionViewLayout: UICollectionViewLayout,         sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {      } //Use for interspacing     func collectionView(collectionView: UICollectionView,         layout collectionViewLayout: UICollectionViewLayout,         minimumInteritemSpacingForSectionAtIndex section: Int) -> CGFloat {             return 1.0     }      func collectionView(collectionView: UICollectionView, layout         collectionViewLayout: UICollectionViewLayout,         minimumLineSpacingForSectionAtIndex section: Int) -> CGFloat {             return 1.0     } 

// For swift 3

func collectionView(_ collectionView: UICollectionView,                     layout collectionViewLayout: UICollectionViewLayout,                     sizeForItemAt indexPath: IndexPath) -> CGSize {  }  func collectionView(_ collectionView: UICollectionView,                     layout collectionViewLayout: UICollectionViewLayout,                     minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {     return 1.0 }  func collectionView(_ collectionView: UICollectionView, layout     collectionViewLayout: UICollectionViewLayout,                     minimumLineSpacingForSectionAt section: Int) -> CGFloat {     return 1.0 } 

// For swift 4

extension MyClass: UICollectionViewDelegateFlowLayout {          func collectionView(_ collectionView: UICollectionView,                             layout collectionViewLayout: UICollectionViewLayout,                             sizeForItemAt indexPath: IndexPath) -> CGSize {          }          func collectionView(_ collectionView: UICollectionView,                             layout collectionViewLayout: UICollectionViewLayout,                             minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {             return 1.0         }          func collectionView(_ collectionView: UICollectionView, layout             collectionViewLayout: UICollectionViewLayout,                             minimumLineSpacingForSectionAt section: Int) -> CGFloat {             return 1.0         }     } 

use the same code as shown above for swift 3 but just make sure your class conforms to protocol UICollectionViewDelegateFlowLayout