UICollectionView information supply and delegates programmatically

UICollectionViewCell programmatically

In the event you’d like so as to add views to your cell, you need to use the init(body:) methodology, and arrange your view hierarchy there. As a substitute of awakeFromNib you need to fashion your views within the init methodology as nicely. You’ll be able to reset all the pieces inside the same old prepareForReuse methodology. As you may see by utilizing anchors generally it’s value 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 carried out")
    }

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

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

UICollectionView programmatically

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

class ViewController: UIViewController {

    weak var collectionView: UICollectionView!

    var information: [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 {
        information.depend
    }

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

        let information = information[indexPath.item]
        cell.textLabel.textual content = String(information)
        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, top: 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 straightforward. Anchors are actually highly effective, Interface Builder is extraordinarily useful, however generally it’s simply sooner to create your views from code. The selection is yours, however please don’t be afraid of coding consumer interfaces! 😅