Reusable views and cell registration and dequeuing (for table views and collection views)

README.md

Reusable views and cell registration and dequeuing (for table views and collection views)

NibLoadableView.swift

protocol NibLoadableView: class {
    static var nibName: String { get }
}

extension NibLoadableView where Self: UIView {
    static var nibName: String {
        return String(describing: self)
    }
}

ReusableView.swift

protocol ReusableView: class {
    static var reusableIdentifier: String { get }
}

extension ReusableView where Self: UIView {
    static var reusableIdentifier: String {
        return String(describing: self)
    }
}

UICollectionView.swift

extension UICollectionView {
    enum SupplementaryViewKind {
        case header
        case footer

        var rawValue: String {
            switch self {
            case .header:
                return UICollectionElementKindSectionHeader
            case .footer:
                return UICollectionElementKindSectionFooter
            }
        }
    }
}

extension UICollectionView {
    func register<T: UICollectionViewCell>(cell: T.Type) where T: ReusableView {
        register(T.self, forCellWithReuseIdentifier: T.reusableIdentifier)
    }

    func register<T: UICollectionViewCell>(cell: T.Type) where T: ReusableView, T: NibLoadableView {
        let nib = UINib(nibName: T.nibName, bundle: Bundle(for: T.self))
        register(nib, forCellWithReuseIdentifier: T.reusableIdentifier)
    }

    func register<T: UICollectionReusableView>(view: T.Type, asSupplementaryViewKind kind: SupplementaryViewKind) where T: ReusableView {
        register(T.self, forSupplementaryViewOfKind: kind.rawValue, withReuseIdentifier: T.reusableIdentifier)
    }

    func register<T: UICollectionReusableView>(view: T.Type, asSupplementaryViewKind kind: SupplementaryViewKind) where T: ReusableView, T: NibLoadableView {
        let nib = UINib(nibName: T.nibName, bundle: Bundle(for: T.self))
        register(nib, forSupplementaryViewOfKind: kind.rawValue, withReuseIdentifier: T.reusableIdentifier)
    }
}

extension UICollectionView {
    func dequeueReusableCell<T: UICollectionViewCell>(forIndexPath indexPath: IndexPath) -> T where T: ReusableView {
        guard let cell = dequeueReusableCell(withReuseIdentifier: T.reusableIdentifier, for: indexPath) as? T else {
            fatalError("Could not dequeue cell with identifier: \(T.reusableIdentifier)")
        }
        return cell
    }

    func dequeueReusableSupplementaryView<T: UICollectionReusableView>(ofKind kind: SupplementaryViewKind, forIndexPath indexPath: IndexPath) -> T where T: ReusableView {
        guard let view = dequeueReusableSupplementaryView(ofKind: kind.rawValue, withReuseIdentifier: T.reusableIdentifier, for: indexPath) as? T else {
            fatalError("Could not dequeue view with identifier: \(T.reusableIdentifier)")
        }
        return view
    }
}

UICollectionViewLayout.swift

extension UICollectionViewLayout {
    func register<T: UICollectionReusableView>(decorationView: T.Type) where T: ReusableView {
        register(T.self, forDecorationViewOfKind: T.reusableIdentifier)
    }

    func register<T: UICollectionReusableView>(decorationView: T.Type) where T: ReusableView, T: NibLoadableView {
        let nib = UINib(nibName: T.nibName, bundle: Bundle(for: T.self))
        register(nib, forDecorationViewOfKind: T.reusableIdentifier)
    }
}

UITableView.swift

extension UITableView {
    func register<T: UITableViewCell>(cell: T.Type) where T: ReusableView {
        register(T.self, forCellReuseIdentifier: T.reusableIdentifier)
    }

    func register<T: UITableViewCell>(cell: T.Type) where T: ReusableView, T: NibLoadableView {
        let nib = UINib(nibName: T.nibName, bundle: Bundle(for: T.self))
        register(nib, forCellReuseIdentifier: T.reusableIdentifier)
    }

    func register<T: UITableViewHeaderFooterView>(headerFooterView: T.Type) where T: ReusableView {
        register(T.self, forHeaderFooterViewReuseIdentifier: T.reusableIdentifier)
    }

    func register<T: UITableViewHeaderFooterView>(headerFooterView: T.Type) where T: ReusableView, T: NibLoadableView {
        let nib = UINib(nibName: T.nibName, bundle: Bundle(for: T.self))
        register(nib, forHeaderFooterViewReuseIdentifier: T.reusableIdentifier)
    }
}

extension UITableView {
    func dequeueReusableCell<T: UITableViewCell>(forIndexPath indexPath: IndexPath) -> T where T: ReusableView {
        guard let cell = dequeueReusableCell(withIdentifier: T.reusableIdentifier, for: indexPath) as? T else {
            fatalError("Could not dequeue cell with identifier: \(T.reusableIdentifier)")
        }
        return cell
    }

    func dequeueReusableHeaderFooterView<T: UITableViewHeaderFooterView>() -> T where T: ReusableView {
        guard let view = dequeueReusableHeaderFooterView(withIdentifier: T.reusableIdentifier) as? T else {
            fatalError("Could not dequeue header/footer view with identifier: \(T.reusableIdentifier)")
        }
        return view
    }
}