Detect font changes on rotation

Question

I have the following viewcontroller

class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {

@IBOutlet weak var collectionView: UICollectionView!

var dogs = ["Dog1", "Dog2","Dog3"]

override func viewDidLoad() {
    super.viewDidLoad()
    collectionView.delegate = self
    collectionView.dataSource = self
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return dogs.count
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CustomCell", for: indexPath) as! CustomCell
     cell.testLabel.text = dogs[indexPath.row]
     return cell
}
}

and the following CustomCell

class CustomCell: UICollectionViewCell {

@IBOutlet weak var testLabel: UILabel!

override func awakeFromNib() {
    super.awakeFromNib()
    if (UIDevice.current.orientation == UIDeviceOrientation.portrait)
    {
       testLabel.font = UIFont(name: "HelveticaNeue-Bold", size: 10)
    }
    else
    {
        testLabel.font = UIFont(name: "HelveticaNeue-Italic", size: 25)
    }
   }
}

I am observing font changes initially when the viewcontroller is accessed but not when I am rotating the device.For example, if the device is in portrait and I access the viewcontroller , I am getting the correct font but if I change it to landscape , it is still showing portrait font.

Similarly, if I go to another viewcontroller and access the present viewcontroller in landscape , it is showing correct font and when I change the orientation to portratit , it is still remembering the landscape font. How do I rectify this?

Answer 1

To solve your problem, you should set testLabel font in cellForItemAt and simply when rotation changes, you just need call reloadData for your collectionView

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CustomCell", for: indexPath) as! CustomCell
    cell.testLabel.text = dogs[indexPath.row]
    if (UIDevice.current.orientation == UIDeviceOrientation.portrait)
    {
       cell.testLabel.font = UIFont(name: "HelveticaNeue-Bold", size: 10)
    }
    else
    {
        cell.testLabel.font = UIFont(name: "HelveticaNeue-Italic", size: 25)
    }
     return cell
}

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    YOUR_COLLECTION_VIEW.reloadData()
}