UIImageView view in UICollectionView cell is not resizing to cell width-CodePudding

I'm creating simple UICollectionView with 3 column per row cells.

My cell is simple - just UIImageView stretched to 4 sides:

class FollowerCell: UICollectionViewCell {
    
    static let reuseID = "FollowerCell"
    
    var avatarImageView:UIImageView!
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        configure()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func configure() {
        avatarImageView = UIImageView()
        addSubview(avatarImageView)
        
        contentView.layer.borderColor = UIColor.red.cgColor
        contentView.layer.cornerRadius = 5
        contentView.layer.borderWidth = 5
        
        avatarImageView.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
            avatarImageView.topAnchor.constraint(equalTo: contentView.topAnchor),
            avatarImageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            avatarImageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            avatarImageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor)
        ])
        
        avatarImageView.image = UIImage(named: "avatar-placeholder")
    }
    
}

In ViewController I define width on cells by implementing UICollectionViewDelegateFlowLayout's method sizeForItemAt:

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        
        let width                       = self.view.bounds.width
        let itemWidth                   = width / 3
        
        return CGSize(width: itemWidth, height: itemWidth)
}

And i have strange result - my UIImageView size ignores cell size (which is red rectangle):

enter image description here

Github:

What i'm missing when creating UICollectionView programmatically ?

Im following tutorial from 2021 where it works just fine, seems something was changed in XCode 11.

CodePudding user response：

Main change

contentView.addSubview(avatarImageView)

Full class

import UIKit

class FollowerCell: UICollectionViewCell {
    static let reuseID = "FollowerCell"
    var avatarImageView:UIImageView!
    override init(frame: CGRect) {
        super.init(frame: frame)
        configure()
    }
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    private func configure() {
        avatarImageView = UIImageView()
        contentView.addSubview(avatarImageView)
        contentView.layer.borderColor = UIColor.red.cgColor
        contentView.layer.cornerRadius = 5
        contentView.layer.borderWidth = 5
        avatarImageView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            avatarImageView.topAnchor.constraint(equalTo: contentView.topAnchor),
            avatarImageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            avatarImageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            avatarImageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor)
        ])
        avatarImageView.image = UIImage(named: "avatar-placeholder")
    }
}