UICollectionView knowledge supply and delegates programmatically

UICollectionViewCell programmatically

If you happen to’d like so as to add views to your cell, you must use the init(body:) technique, and arrange your view hierarchy there. As a substitute of awakeFromNib you must fashion your views within the init technique as properly. You may reset every part inside the standard prepareForReuse technique. As you’ll be able to see by utilizing anchors generally it’s price to ditch IB fully. 🎉

class Cell: UICollectionViewCell {

    static var identifier: String = "Cell"

    weak var textLabel: UILabel!

    override init(body: CGRect) {
        tremendous.init(body: body)

        let textLabel = UILabel(body: .zero)
        textLabel.translatesAutoresizingMaskIntoConstraints = false
        contentView.addSubview(textLabel)
        NSLayoutConstraint.activate([
            contentView.centerXAnchor.constraint(equalTo: textLabel.centerXAnchor),
            contentView.centerYAnchor.constraint(equalTo: textLabel.centerYAnchor),
        ])
        self.textLabel = textLabel
        reset()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been applied")
    }

    override func prepareForReuse() {
        tremendous.prepareForReuse()
        
        reset()
    }

    func reset() {
        textLabel.textAlignment = .heart
    }
}

UICollectionView programmatically

Creating assortment view controllers utilizing solely Swift code requires only some further strains. You may implement loadView and create your UICollectionView object there. Retailer a weak reference of it contained in the controller, and the remainder is identical.

class ViewController: UIViewController {

    weak var collectionView: UICollectionView!

    var knowledge: [Int] = Array(0..<10)

    override func loadView() {
        tremendous.loadView()

        let collectionView = UICollectionView(
            body: .zero, 
            collectionViewLayout: UICollectionViewFlowLayout()
        )
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(collectionView)
        NSLayoutConstraint.activate([
            view.topAnchor.constraint(equalTo: collectionView.topAnchor),
            view.bottomAnchor.constraint(equalTo: collectionView.bottomAnchor),
            view.leadingAnchor.constraint(equalTo: collectionView.leadingAnchor),
            view.trailingAnchor.constraint(equalTo: collectionView.trailingAnchor),
        ])
        collectionView = collectionView
    }

    override func viewDidLoad() {
        tremendous.viewDidLoad()

        collectionView.dataSource = self
        collectionView.delegate = self
        collectionView.register(Cell.self, forCellWithReuseIdentifier: Cell.identifier)
        collectionView.alwaysBounceVertical = true
        collectionView.backgroundColor = .white
    }
}

extension ViewController: UICollectionViewDataSource {

    func collectionView(
        _ collectionView: UICollectionView,
        numberOfItemsInSection part: Int
    ) -> Int {
        knowledge.depend
    }

    func collectionView(
        _ collectionView: UICollectionView,
        cellForItemAt indexPath: IndexPath
    ) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(
            withReuseIdentifier: Cell.identifier, 
            for: indexPath
        ) as! Cell

        let knowledge = knowledge[indexPath.item]
        cell.textLabel.textual content = String(knowledge)
        return cell
    }
}

extension ViewController: UICollectionViewDelegate {

    func collectionView(
        _ collectionView: UICollectionView, 
        didSelectItemAt indexPath: IndexPath
    ) {

    }
}

extension ViewController: UICollectionViewDelegateFlowLayout {

    func collectionView(
        _ collectionView: UICollectionView,
        format collectionViewLayout: UICollectionViewLayout,
        sizeForItemAt indexPath: IndexPath
    ) -> CGSize {
        .init(width: collectionView.bounds.width, peak: 44)
    }

    func collectionView(
        _ collectionView: UICollectionView,
        format collectionViewLayout: UICollectionViewLayout,
        insetForSectionAt part: Int
    ) -> UIEdgeInsets {
        .init(high: 0, left: 0, backside: 0, proper: 0) //.zero
    }

    func collectionView(
        _ collectionView: UICollectionView,
        format collectionViewLayout: UICollectionViewLayout,
        minimumInteritemSpacingForSectionAt part: Int
    ) -> CGFloat {
        0
    }

    func collectionView(
        _ collectionView: UICollectionView,
        format collectionViewLayout: UICollectionViewLayout,
        minimumLineSpacingForSectionAt part: Int
    ) -> CGFloat {
        0
    }
}

That was simple. Anchors are actually highly effective, Interface Builder is extraordinarily useful, however generally it’s simply quicker to create your views from code. The selection is yours, however please don’t be afraid of coding person interfaces! 😅