TargetActionSectionFooterTitleView.swift

import UIKit

/**
 A drop-in replacement for the `UITableView`’s default section footer title, adding support for inline links. This class
 will call the same, single target/action pair for *all* inline links, regardless of what their `NSLinkAttributeName`
 values are. If you need to support multiple different inline links, this class is not for you.
 
 Instead of implementing `tableView(tableView:titleForFooterInSection:)` and returning a string, implement
 `tableView(tableView:, viewForFooterInSection section: Int)` and return an instance of this class.
 
 You’ll also want to implement `tableView(tableView: UITableView, heightForFooterInSection section: Int)` and return
 something along the lines of `footerView.sizeThatFits(CGSize(width: tableView.bounds.width, height: .max)).height`.
 */
public final class TargetActionSectionFooterTitleView: UIView {
    private enum Constants {
        /*
         Match the default used by `UITableView` when `tableView(tableView:titleForFooterInSection:)` is implemented
         (determined via trial and error).
         */
        
        static let fontSize: CGFloat = 13
        static let lineSpacing: CGFloat = 2.2
        static let textColor: UIColor = UIColor(colorLiteralRed: 109/255, green: 109/255, blue: 114/255, alpha: 1)
        
        static let containerTopBottomMargin: CGFloat = 8.5
        static let containerLeftRightMargin: CGFloat = 10
    }
    
    // MARK: - Subviews
    
    private let textView = UITextView()
    
    // MARK: - Inputs
    
    private let targetAction: WeakTargetAction
    
    // MARK: - Initialization
    
    public init(attributedText: NSAttributedString, targetAction: WeakTargetAction) {
        self.targetAction = targetAction
        
        super.init(frame: .zero)
        
        textView.textContainerInset = UIEdgeInsets(
            top: Constants.containerTopBottomMargin,
            left: Constants.containerLeftRightMargin,
            bottom: Constants.containerTopBottomMargin,
            right: Constants.containerLeftRightMargin
        )
        textView.translatesAutoresizingMaskIntoConstraints = false
        textView.delegate = self
        textView.editable = false
        textView.scrollEnabled = false
        textView.attributedText = {
            // Match `UITableView`’s default footer title text style
            
            let mutableCopy = attributedText.mutableCopy() as! NSMutableAttributedString
            mutableCopy.addAttributes(
                [
                    NSParagraphStyleAttributeName: {
                        let paragraphStyle = NSMutableParagraphStyle()
                        paragraphStyle.lineSpacing = Constants.lineSpacing
                        return paragraphStyle
                    }(),
                    NSFontAttributeName: UIFont.systemFontOfSize(Constants.fontSize),
                    NSForegroundColorAttributeName: Constants.textColor,
                ],
                range: NSRange(location: 0, length: attributedText.length)
            )
            
            return mutableCopy
        }()
        
        addSubview(textView)
        
        NSLayoutConstraint.activateConstraints([
            textView.topAnchor.constraintEqualToAnchor(topAnchor),
            textView.leadingAnchor.constraintEqualToAnchor(leadingAnchor),
            textView.trailingAnchor.constraintEqualToAnchor(trailingAnchor),
            textView.bottomAnchor.constraintEqualToAnchor(bottomAnchor),
        ])
    }
    
    public required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - UIView
    
    public override func sizeThatFits(size: CGSize) -> CGSize {
        return textView.sizeThatFits(size)
    }
}

WeakTargetAction.swift

import Foundation

/**
 A wrapper around a target/action pair, holding the target weakly since the target (e.g. a view controller) often holds
 a strong reference to the object that ends up owning the `WeakTargetAction` instance (e.g. a view).
 */
public final class WeakTargetAction {
    weak var target: AnyObject?
    let action: Selector
    
    public init(target: AnyObject, action: Selector) {
        self.target = target
        self.action = action
    }
}