版本记录

前言

iOS中有关视图控件用户能看到的都在UIKit框架里面，用户交互也是通过UIKit进行的。感兴趣的参考上面几篇文章。
1. UIKit框架（一） —— UIKit动力学和移动效果（一）
2. UIKit框架（二） —— UIKit动力学和移动效果（二）
3. UIKit框架（三） —— UICollectionViewCell的扩张效果的实现（一）
4. UIKit框架（四） —— UICollectionViewCell的扩张效果的实现（二）
5. UIKit框架（五） —— 自定义控件：可重复使用的滑块（一）
6. UIKit框架（六） —— 自定义控件：可重复使用的滑块（二）
7. UIKit框架（七） —— 动态尺寸UITableViewCell的实现（一）
8. UIKit框架（八） —— 动态尺寸UITableViewCell的实现（二）
9. UIKit框架（九） —— UICollectionView的数据异步预加载（一）
10. UIKit框架（十） —— UICollectionView的数据异步预加载（二）
11. UIKit框架（十一） —— UICollectionView的重用、选择和重排序（一）
12. UIKit框架（十二） —— UICollectionView的重用、选择和重排序（二）
13. UIKit框架（十三） —— 如何创建自己的侧滑式面板导航（一）
14. UIKit框架（十四） —— 如何创建自己的侧滑式面板导航（二）
15. UIKit框架（十五） —— 基于自定义UICollectionViewLayout布局的简单示例（一）
16. UIKit框架（十六） —— 基于自定义UICollectionViewLayout布局的简单示例（二）
17. UIKit框架（十七） —— 基于自定义UICollectionViewLayout布局的简单示例（三）
18. UIKit框架（十八） —— 基于CALayer属性的一种3D边栏动画的实现（一）
19. UIKit框架（十九） —— 基于CALayer属性的一种3D边栏动画的实现（二）
20. UIKit框架（二十） —— 基于UILabel跑马灯类似效果的实现（一）
21. UIKit框架（二十一） —— UIStackView的使用（一）
22. UIKit框架（二十二） —— 基于UIPresentationController的自定义viewController的转场和展示（一）
23. UIKit框架（二十三） —— 基于UIPresentationController的自定义viewController的转场和展示（二）
24. UIKit框架（二十四） —— 基于UICollectionViews和Drag-Drop在两个APP间的使用示例 （一）
25. UIKit框架（二十五） —— 基于UICollectionViews和Drag-Drop在两个APP间的使用示例 （二）
26. UIKit框架（二十六） —— UICollectionView的自定义布局 （一）
27. UIKit框架（二十七） —— UICollectionView的自定义布局 （二）
28. UIKit框架（二十八） —— 一个UISplitViewController的简单实用示例 （一）
29. UIKit框架（二十九） —— 一个UISplitViewController的简单实用示例 （二）
30. UIKit框架（三十） —— 基于UICollectionViewCompositionalLayout API的UICollectionViews布局的简单示例（一）
31. UIKit框架（三十一） —— 基于UICollectionViewCompositionalLayout API的UICollectionViews布局的简单示例（二）
32. UIKit框架（三十二） —— 替换Peek and Pop交互的基于iOS13的Context Menus（一）
33. UIKit框架（三十三） —— 替换Peek and Pop交互的基于iOS13的Context Menus（二）
34. UIKit框架（三十四） —— Accessibility的使用（一）

源码

1. Swift

首先看下工程组织结构

下面看下sb中的内容

接着就是源码了

1. InstructionViewModel.swift

import Foundation

enum RecipeInstructionType {
  case ingredient, cookingInstructions
}

struct InstructionViewModel {
  let recipe: Recipe?
  var type: RecipeInstructionType
  var ingredientsState: [Bool] = []
  var directionsState: [Bool] = []
  
  init(recipe: Recipe, type: RecipeInstructionType) {
    self.recipe = recipe
    self.type = type
    
    if let ingredients = recipe.ingredients {
      ingredientsState = [Bool](repeating: false, count:ingredients.count)
    }
    
    if let directions = recipe.directions {
      directionsState = [Bool](repeating: false, count:directions.count)
    }
  }
  
  mutating func numberOfItems() -> Int {
    switch type {
    case .ingredient:
      if let ingredients = recipe?.ingredients {
        return ingredients.count
      }
    case .cookingInstructions:
      if let directions = recipe?.directions {
        return directions.count
      }
    }
    return 0
  }
  
  func numberOfSections() -> Int {
    return 1
  }
  
  func itemFor(_ index: Int) -> String? {
    switch type {
    case .ingredient:
      if let ingredients = recipe?.ingredients {
        return ingredients[index]
      }
    case .cookingInstructions:
      if let directions = recipe?.directions {
        return directions[index]
      }
    }
    return nil
  }
  
  func getStateFor(_ index: Int) -> Bool {
    switch type {
    case .ingredient:
      return ingredientsState[index]
    case .cookingInstructions:
      return directionsState[index]
    }
  }
  
  mutating func selectItemFor(_ index: Int) {
    switch type {
    case .ingredient:
      ingredientsState[index].toggle()
    case .cookingInstructions:
      directionsState[index].toggle()
    }
  }
}

2. Recipe.swift

import UIKit

// Data from: http://damndelicious.net/recipe-index/

enum RecipeDifficulty {
  case unknown
  case rating(Int)
}

extension RecipeDifficulty {
  init?(value: Int) {
    if value > 0 && value <= 5 {
      self = .rating(value)
    } else {
      self = .unknown
    }
  }
}

struct Recipe {
  let name: String
  let difficulty: RecipeDifficulty
  let photo: UIImage?
  let photoDescription: String
  let prepTime: Int
  let cookTime: Int
  let yield: Int
  let ingredients: [String]?
  let directions: [String]?
}

extension Recipe {
  init?(dict: [String: AnyObject]) {
    guard
      let name = dict["name"] as? String,
      let rawDifficulty = dict["difficulty"] as? Int,
      let difficulty = RecipeDifficulty(value: rawDifficulty),
      let prepTime = dict["prepTime"] as? Int,
      let cookTime = dict["cookTime"] as? Int,
      let yield = dict["yield"] as? Int,
      let ingredients = dict["ingredients"] as? [String],
      let directions = dict["directions"] as? [String],
      let photoDescription = dict["photoDescription"] as? String
      else {
        return nil
    }
    
    self.name = name
    self.difficulty = difficulty
    self.prepTime = prepTime
    self.cookTime = cookTime
    self.yield = yield
    self.ingredients = ingredients
    self.directions = directions
    self.photoDescription = photoDescription
    
    if let imageName = dict["imageName"] as? String, !imageName.isEmpty {
      photo = UIImage(named: imageName)
    } else {
      photo = nil
    }
  }
}

// MARK: - Load Sample Data

extension Recipe {
  static func loadDefaultRecipe() -> [Recipe]? {
    return self.loadRecipeFrom("RecipeList")
  }
  
  static func loadRecipeFrom(_ plistName: String) -> [Recipe]? {
    guard
      let path = Bundle.main.path(forResource: plistName, ofType: "plist"),
      let array = NSArray(contentsOfFile: path) as? [[String: AnyObject]]
      else {
        return nil
    }
    
    return array.compactMap { Recipe(dict: $0) }
  }
}

3. RecipeInstructionsViewController.swift

import UIKit

class RecipeInstructionsViewController: UITableViewController {
  private var headerView: UIView!
  private var instructionViewModel: InstructionViewModel!
  var recipe: Recipe!
  var didLikeFood = true
  @IBOutlet var likeButton: UIButton!
  @IBOutlet var backButton: UIButton!
  @IBOutlet var dishImageView: UIImageView!
  @IBOutlet var dishLabel: UILabel!
  
  override var prefersStatusBarHidden: Bool {
    return true
  }
  
  override func viewDidLoad() {
    super.viewDidLoad()
    
    assert(recipe != nil)
    
    backButton.accessibilityLabel = "back"
    backButton.accessibilityTraits = UIAccessibilityTraits.button
    
    isLikedFood(true)
    instructionViewModel = InstructionViewModel(recipe: recipe, type: .ingredient)
    setupRecipe()
    setupTableView()
  }
  
  // MARK: - Action Outlets
  
  @IBAction func likeButtonPressed(_ sender: AnyObject) {
    isLikedFood(!didLikeFood)
  }
  
  func isLikedFood(_ liked: Bool) {
    if liked {
      likeButton.setTitle("😍", for: .normal)
      likeButton.accessibilityLabel = "Like"
      likeButton.accessibilityTraits = UIAccessibilityTraits.button
      didLikeFood = true
    } else {
      likeButton.setTitle("😖", for: .normal)
      likeButton.accessibilityLabel = "Dislike"
      likeButton.accessibilityTraits = UIAccessibilityTraits.button
      didLikeFood = false
    }
  }
  
  @IBAction func toggleSegment(_ sender: UISegmentedControl) {
    if sender.selectedSegmentIndex == 0 { // Ingredients
      instructionViewModel.type = .ingredient
    } else { //Instruction
      instructionViewModel.type = .cookingInstructions
    }
    tableView.reloadData()
  }
  
  @IBAction func tapBackButton(_ sender: AnyObject) {
    navigationController?.popViewController(animated: true)
  }
  
  // MARK: - TableView Data Source
  
  override func numberOfSections(in tableView: UITableView) -> Int {
    return instructionViewModel.numberOfSections()
  }
  
  override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return instructionViewModel.numberOfItems()
  }
  
  override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: InstructionCell.self), for: indexPath) as! InstructionCell
    
    if let description = instructionViewModel.itemFor(indexPath.item) {
      cell.configure(description)
    }
    
    let strike = instructionViewModel.getStateFor(indexPath.item)
    cell.shouldStrikeThroughText(strike)
    
    return cell
  }
  
  // MARK: - TableView Delegate
  
  override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    tableView.deselectRow(at: indexPath, animated: true)
    instructionViewModel.selectItemFor(indexPath.item)
    let cell = tableView.cellForRow(at: indexPath) as! InstructionCell
    let strike = instructionViewModel.getStateFor(indexPath.item)
    cell.shouldStrikeThroughText(strike)
  }
}

// MARK: - Setup

extension RecipeInstructionsViewController {
  func setupRecipe() {
    dishImageView.image = recipe.photo
    dishLabel.text = recipe.name
  }
  
  func setupTableView() {
    tableView.estimatedRowHeight = 79
    tableView.rowHeight = UITableView.automaticDimension
  }
}

4. RecipeListViewController.swift

import UIKit

class RecipeListViewController: UITableViewController {
  var recipes: [Recipe] = []
  var selectedRecipe: Recipe?
  
  override func viewDidLoad() {
    super.viewDidLoad()
    
    if let seedRecipe = Recipe.loadDefaultRecipe() {
      recipes += seedRecipe
      recipes = recipes.sorted(by: { $0.name < $1.name })
    }
    
    tableView.estimatedRowHeight = 100
    tableView.rowHeight = UITableView.automaticDimension
  }
  
  override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    navigationController?.setNavigationBarHidden(true, animated: true)
  }
  
  override func viewWillAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    navigationController?.setNavigationBarHidden(false, animated: true)
  }
  
  override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "showRecipe" {
      if let vc = segue.destination as? RecipeInstructionsViewController {
        vc.recipe = selectedRecipe
      }
    }
  }
  
  // MARK: - TableView Data Source
  
  override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return recipes.count
  }
  
  override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: RecipeCell.self), for: indexPath) as! RecipeCell
    let recipe = recipes[indexPath.item]
    cell.configureCell(with: recipe)
    return cell
  }
  
  // MARK: - TableView Delegate
  
  override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    tableView.deselectRow(at: indexPath, animated: true)
    selectedRecipe = recipes[indexPath.item]
    performSegue(withIdentifier: "showRecipe", sender: self)
  }
}

5. InstructionCell.swift

import UIKit

class InstructionCell: UITableViewCell {
  @IBOutlet var checkmarkButton: UIButton!
  @IBOutlet var descriptionLabel: UILabel!
  
  func configure(_ description: String) {
    descriptionLabel.attributedText = nil
    descriptionLabel.text = description
  }
  
  @IBAction func checkmarkTapped(_ sender: AnyObject) {
    shouldStrikeThroughText(!checkmarkButton.isSelected)
  }
  
  func shouldStrikeThroughText(_ strikeThrough: Bool) {
    guard let text = descriptionLabel.text else {
      return
    }
    
    let attributeString =  NSMutableAttributedString(string: text)
    
    // 1
    checkmarkButton.isAccessibilityElement = false
    
    if strikeThrough {
      // 2
      descriptionLabel.accessibilityLabel = "Completed: \(text)"
      attributeString.addAttribute(NSAttributedString.Key.strikethroughStyle, value: 2, range: NSRange(text.startIndex..., in: text))
    } else {
      // 3
      descriptionLabel.accessibilityLabel = "Uncompleted: \(text)"
    }
    
    let buttonImage = strikeThrough ? UIImage(named: "icon-check") : UIImage(named: "icon-empty")
    checkmarkButton.setImage(buttonImage, for: .normal)
    descriptionLabel.attributedText = attributeString
  }
}

6. RecipeCell.swift

import UIKit

class RecipeCell: UITableViewCell {
  @IBOutlet var roundedBackgroundView: UIView!
  @IBOutlet var foodImageView: UIImageView!
  @IBOutlet var dishNameLabel: UILabel!
  @IBOutlet var difficultyLabel: UILabel!
  var difficultyValue: RecipeDifficulty = .unknown
  
  override func awakeFromNib() {
    super.awakeFromNib()
    styleAppearance()
  }
  
  func configureCell(with recipe:Recipe) {
    dishNameLabel.text = recipe.name
    foodImageView.image = recipe.photo
    difficultyValue = recipe.difficulty
    difficultyLabel.text = difficultyString
    applyAccessibility(recipe)
  }
  
  var difficultyString: String {
    switch difficultyValue {
    case .unknown:
      return ""
    case .rating(let value):
      var string = ""
      for _ in 0..<value {
        string.append("🍲")
      }
      return string
    }
  }
  
  func styleAppearance() {
    roundedBackgroundView.layer.cornerRadius = 3.0
    roundedBackgroundView.layer.masksToBounds = false
    roundedBackgroundView.layer.shadowOffset = CGSize(width: 0, height: 0)
    roundedBackgroundView.layer.shadowColor = #colorLiteral(red: 0.05439098924, green: 0.1344551742, blue: 0.1884709597, alpha: 1).cgColor
    roundedBackgroundView.layer.shadowRadius = 1.0
    roundedBackgroundView.layer.shadowOpacity = 0.3
    
    foodImageView.layer.cornerRadius = 3.0
  }
  
  override func setSelected(_ selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)
  }
}

// MARK: Accessibility

extension RecipeCell {
  func applyAccessibility(_ recipe: Recipe) {
    // 1
    foodImageView.accessibilityTraits = UIAccessibilityTraits.image
    // 2
    foodImageView.accessibilityLabel = recipe.photoDescription
    
    // 1
    difficultyLabel.isAccessibilityElement = true
    // 2
    difficultyLabel.accessibilityTraits = UIAccessibilityTraits.none
    // 3
    difficultyLabel.accessibilityLabel = "Difficulty Level"
    // 4
    switch recipe.difficulty {
    case .unknown:
      difficultyLabel.accessibilityValue = "Unknown"
    case .rating(let value):
      difficultyLabel.accessibilityValue = "\(value)"
    }
    
    difficultyLabel.font = UIFont.preferredFont(forTextStyle: .body)
    difficultyLabel.adjustsFontForContentSizeCategory = true
  }
}

后记

本篇主要讲述了Accessibility的使用，感兴趣的给个赞或者关注~~~