Components

This repository will contain some useful iOS code utils and extensions.

Requirements:

• iOS 9.0+
• Xcode 9.0+
• Swift 4.0+

UI Layer

1. Work with UITableView & UICollectionView - one possible approach, inspired by CocoaHeads:

You can move configuration logic for UITableViewCell or UICollectionViewCell from -cellForRowAtIndexPath: to separate types.

First, you need to create cell class and appropriate type that conforms to CellViewModel type:

public typealias AnyViewCell = UIView

public protocol CellViewModel: AnyCellViewModel {
    associatedtype Cell: AnyViewCell
    func setup(cell: Cell)
}

UserTableViewCell.swift

// MARK: - View Model

struct UserCellModel: CellViewModel {
    var user: User
    
    func setup(cell: UserTableViewCell) {
        cell.nameLabel.text = user.name
    }
}

// MARK: - Cell

final class UserTableViewCell: UITableViewCell {
    @IBOutlet weak var nameLabel: UILabel!
}

After that you need to register created model type:

tableView.register(nibModel: UserCellModel.self)

Then store your models in array (or your custom datasource type):

private var users: [AnyCellViewModel] = []

AnyCellViewModel is a base protocol of CellViewModel. It's needed only in order to fix compiler limitation as you can use protocols with associatedtype only as generic constraints and can't write something like this:

private var users: [CellViewModel] = [] // won't compile

UITableViewDataSource implementation is very easy, even if you have multiple cell types, because all logic are contained in our view models:

class ViewController: UIViewController {
    
    @IBOutlet weak var tableView: UITableView!
    
    private var users: [AnyCellViewModel] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        users = User.testDataSource.map { UserCellModel(user: $0) }
        tableView.register(nibModel: UserCellModel.self)
    }
}

extension ViewController: UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return users.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        return tableView.dequeueReusableCell(withModel: tableModel(at: indexPath), for: indexPath)
    }
    
    private func tableModel(at indexPath: IndexPath) -> AnyCellViewModel {
        return users[indexPath.row]
    }
}

See implementation details in Sources folder.

2. Keyboard Handling

Conform your view controller to KeyboardInteracting protocol:

public typealias KeyboardInputView = UIView & UITextInput

public protocol KeyboardInteracting: class {
    var scrollView: UIScrollView! { get }
    var keyboardInputViews: [KeyboardInputView] { get }
    
    func handleKeyboardShow(userInfo: [AnyHashable: Any])
    func handleKeyboardHide()
}

extension KeyboardInteracting where Self: UIViewController {

    func handleKeyboardShow(userInfo: [AnyHashable: Any]) {
        /// ...
    }

    func handleKeyboardHide() {
        // ...
    }
}

KeyboardInteracting.swift

Register and unregister for keyboard notifications:

extension UIViewController {
    public func registerForKeyboardNotifications() {
        let center = NotificationCenter.default
        center.addObserver(self, selector: #selector(keyboardDidShow(notification:)), name: .UIKeyboardDidShow, object: nil)
        center.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: .UIKeyboardWillHide, object: nil)
    }
    
    public func unregisterForKeyboardNotifications() {
        let center = NotificationCenter.default
        center.removeObserver(self, name: .UIKeyboardDidShow, object: nil)
        center.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
    }
    
    @objc private func keyboardDidShow(notification: Notification) {
        guard let userInfo = notification.userInfo else { return }
        (self as? KeyboardInteracting)?.handleKeyboardShow(userInfo: userInfo)
    }
    
    @objc private func keyboardWillHide(notification: Notification) {
        (self as? KeyboardInteracting)?.handleKeyboardHide()
    }
}

And handle UIViewController life cycle:

class ViewController: UIViewController, KeyboardInteracting {
    var scrollView: UIScrollView!
    
    var keyboardInputViews: [KeyboardInputView] {
        // return an array of your input views
        return [] 
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        registerForKeyboardNotifications()
    }
    
    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)
        unregisterForKeyboardNotifications()
    }
    
    // ...
}

Extensions

1. Bundle

extension Bundle {
    public var bundleIdentifier: String {
        return object(forInfoDictionaryKey: kCFBundleIdentifierKey as String) as! String
    }
    
    /// Project bundle name
    public var bundleName: String {
        return object(forInfoDictionaryKey: kCFBundleNameKey as String) as! String
    }
    
    /// App name which displaying in Springboard
    public var displayName: String {
        let displayName = object(forInfoDictionaryKey: "CFBundleDisplayName") as? String
        return displayName ?? self.bundleName
    }
    
    public var buildVersion: String? {
        return object(forInfoDictionaryKey: kCFBundleVersionKey as String) as? String
    }
}

License

Repository is created under the MIT license. See LICENSE for details.