以编程方式更改集合视图单元格中标签的字体

Question

I have a CollectionViewController as follows

class CollectionViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource{

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

@IBOutlet weak var collectionView: UICollectionView!

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

class CustomCell: UICollectionViewCell {

    @IBOutlet weak var testLabel: UILabel!
}

I like to change the font size as 18 above, but I am getting the font that I set in the storyboard manually. So is there a way that I can change font programatically in the controller or do I need to change it in CustomCell

PS Just found out this happens, when I set manually fonts on device sizes available and if I remove those manual device sizes it works. Is there anyway I can override this and have both at same time?

Answer 1

this was my problem. and its solution very simple All we have to do is first specify font with correct font string name then add string ie cell.testLabel.font = UIFont(name: "HelveticaNeue", size: 18) cell.testLabel.text = dogs[indexPath.row]

Answer 2

Directly change in "cellForItemAt" method as

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

   let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CustomCell", for: indexPath) as! CustomCell
    cell.testLabel.text = ["Dog1", "Dog2", "Dog3"]

    cell.testLabel.font = UIFont(name: "HelveticaNeue", size: 18)

    return cell
}

Answer 3

use this code it will help you

label.font = label.font.fontWithSize(20) //20 is font size

Swift 3:

label.font = label.font.withSize(20)

or try

UIFont.systemFont(ofSize: 18)

Answer 4

use awakeFromNib method, from apple documentation ,

The nib-loading infrastructure sends an awakeFromNib message to each object recreated from a nib archive, but only after all the objects in the archive have been loaded and initialized. When an object receives an awakeFromNib message, it is guaranteed to have all its outlet and action connections already established.

you can change the label font in this method.

class CustomCell: UICollectionViewCell {
    @IBOutlet weak var testLabel: UILabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        testLabel.font = UIFont(name: "HelveticaNeue", size: 18)
    }
}

Answer 5

You need to change cellForItemAt to be this:

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

      let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CustomCell", for: indexPath) as! CustomCell

      cell.testLabel.text = "Dog 1"
      cell.testLabel.font = UIFont(name: "HelveticaNeue", size: 18)

      return cell
}

Then please check the following:

1. Your reuse identifier is setup correctly in the storyboard.
2. Your collectionView delegate is set.
3. Your collectionView datasource is set.
4. The outlet for the label is connected.
5. You reload the collectionView data
6. Check the font name is correct, you can use FontBook on the mac to check spelling.

Answer 6

First of all I don't understand why have you written func viewDidLayoutSubviews() inside cellForItemAt delegate method. Just remove it from there.

Secondly, you don't need to call collectionView.reloadData() in viewDidLoad() since it will automatically load the collectionView first time with the data you provided.

Before proceeding to changing the font, check if your required font (HelveticaNeue) is available in the system. If not first install the font and add it to your project.

Now coming to changing the font of the label . It can be done in 2 ways:

1. Use awakeFromNib() in your CustomCell , ie

class CustomCell: UICollectionViewCell
{
    @IBOutlet weak var testLabel: UILabel!

    override func awakeFromNib()
    {
        super.awakeFromNib()
        self.testLabel.font = UIFont(name: "HelveticaNeue", size: 18)
    }
}

This will set the cell's font only once when the cell is loaded from the nib . It is recommended if there are no further changes in the label's font after configuring it once.

2. Configure the font in cellForItemAt , ie

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
{
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CustomCell", for: indexPath) as! CustomCell
    cell.testLabel.text = dogs[indexPath.row]
    cell.testLabel.font = UIFont(name: "HelveticaNeue", size: 18)
    return cell
}

This will set the cell's font each time cellForItemAt delegate method is called , ie every-time the cell is reloaded. Use this if you want to make any conditional changes in the cells when reloading.