Titled View

TitledView.swift

private final class TopTitledView<T: UIView>: UIView {
    
    private var titleLabel: UILabel!
    private let contentView: T
    private let title: String
    
    init(contentView: T, title: String) {
        self.contentView = contentView
        self.title = title
        super.init(frame: .zero)
        setup()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func setup() {
        setupTitleLabel()
        configureTitleLabelConstraints()
        setupContentView()
    }
    
    func setupTitleLabel() {
        titleLabel = UILabel()
        addSubview(titleLabel)
        
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        
        titleLabel.text = title
        titleLabel.textAlignment = .center
        titleLabel.font = UIFont.preferredFont(forTextStyle: .title1)
        
        titleLabel.textColor = UIColor.black
        titleLabel.numberOfLines = 0
    }
    
    func configureTitleLabelConstraints() {
        titleLabel.leading(equalTo: leadingAnchor, constant: 8.0)
        titleLabel.trailing(equalTo: trailingAnchor, constant: -8.0)
        titleLabel.top(equalTo: topAnchor, constant: 8.0)
        titleLabel.enableContentHugging()
        titleLabel.enableContentCompression()
    }
    
    func setupContentView() {
        addSubview(contentView)
        contentView.translatesAutoresizingMaskIntoConstraints = false
        let topConstraint = contentView.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 8.0)
            topConstraint.isActive = true
        topConstraint.priority = UILayoutPriority(999)
        contentView.centerXAnchor.constraint(equalTo: centerXAnchor, constant: 0.0).isActive = true
        contentView.bottom(equalTo: bottomAnchor, constant: -8.0)
    }
}

private final class BottomTitledView<T: UIView>: UIView {
    
    private var titleLabel: UILabel!
    private let contentView: T
    private let title: String
    
    init(contentView: T, title: String) {
        self.contentView = contentView
        self.title = title
        super.init(frame: .zero)
        setup()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func setup() {
        setupTitleLabel()
        setupContentView()
        configureTitleLabelConstraints()
    }
    
    func setupTitleLabel() {
        titleLabel = UILabel()
        addSubview(titleLabel)
        
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        
        titleLabel.text = title
        titleLabel.textAlignment = .center
        titleLabel.font = UIFont.preferredFont(forTextStyle: .title1)
        
        titleLabel.textColor = UIColor.black
        titleLabel.numberOfLines = 0
    }
    
    func configureTitleLabelConstraints() {
        titleLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 8.0).isActive = true
        titleLabel.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -8.0).isActive = true
        let topConstraint = titleLabel.topAnchor.constraint(equalTo: contentView.bottomAnchor, constant: 8.0)
        topConstraint.isActive = true
        topConstraint.priority = UILayoutPriority(999)
        titleLabel.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -8.0).isActive = true
        titleLabel.enableContentHugging()
        titleLabel.enableContentCompression()
    }
    
    func setupContentView() {
        addSubview(contentView)
        contentView.translatesAutoresizingMaskIntoConstraints = false
        contentView.topAnchor.constraint(equalTo: topAnchor, constant: 8.0).isActive = true
        contentView.centerXAnchor.constraint(equalTo: centerXAnchor, constant: 0.0).isActive = true
    }
}

class TitledView<T: UIView>: UIView {
    
    private var titleLabel: UILabel!
    
    enum Position {
        case top
        case bottom
    }
    
    let contentView: T
    let title: String
    let position: Position
    
    init(view: T, title: String, position: Position) {
        self.contentView = view
        self.title = title
        self.position = position
        super.init(frame: .zero)
        setup()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override var intrinsicContentSize: CGSize {
        var contentFrame: CGRect = .zero
        for subview in subviews {
            contentFrame = contentFrame.union(subview.frame)
        }
        return CGSize(width: contentFrame.width + 16.0, height: contentFrame.height + 16.0)
    }
}

private extension TitledView {
    
    func setup() {
        let view: UIView
        switch position {
        case .top:
            view = TopTitledView(contentView: contentView, title: title)
        case .bottom:
            view = BottomTitledView(contentView: contentView, title: title)
        }
        addSubview(view)
        view.translatesAutoresizingMaskIntoConstraints = false
        
        view.edges(equalTo: self, inset: .zero)
    }
}