1. edgesForExtendedLayout 設(shè)置為 None

• OC

  self.edgesForExtendedLayout = UIRectEdgeNone;
  

• Swift

  // Swift 沒有 None 選項(xiàng)，通過初始化設(shè)置
  self.edgesForExtendedLayout = UIRectEdge.init(rawValue: 0)
  或
  edgesForExtendedLayout = UIRectEdge.init(rawValue: 0)    // 編碼規(guī)范(風(fēng)格)區(qū)別
  

由于導(dǎo)航欄是半透明的，設(shè)置為 None 時(shí)會(huì)顯示黑色，需要設(shè)置self.navigationController.navigationBar.translucent = NO; 或navigationController?.navigationBar.isTranslucent = false

2. 自定義 UIView 底層支持圖層（CALayer），這里以設(shè)置為 AVPlayerLayer 為例

• OC

  // 重寫類方法
  + (Class)layerClass {
      return [AVPlayerLayer class]
  }
  // 在需要的地方設(shè)置圖層的相關(guān)的屬性，avPlayer = AVPlayer()
  [(AVPlayerLayer *)[self layer] setPlayer:avPlayer];
  

• Swift

  override class var layerClass: AnyClass  {
     get {
         return AVPlayerLayer.self
     }
  }
  // 設(shè)置屬性
  guard let avPlayerLayer = self.layer as? AVPlayerLayer else {
      return
  }
  avPlayerLayer.player = avPlayer
  

3. 通過類名字符串初始化對(duì)象，以 HomeViewController 為例

• OC

  NSString *className = @"HomeViewController";
  HomeViewController *homeViewController = [[NSClassFromString(className) alloc] init];
  

• Swift

  let classString = "HomeViewController"
  let className = Bundle.main.infoDictionary!["CFBundleName"] as! String + "." + classString // 這里項(xiàng)目名不能帶有下劃線 “_” 或 “*” 等特殊字符
  let viewControllerClass = NSClassFromString(className) as! UIViewController.Type
  let homeViewController  = viewControllerClass.init()
  

4. 單例模式實(shí)現(xiàn)

• OC

  static Singleton* _instance = nil;  
  + (instancetype) shareInstance {  
      static dispatch_once_t onceToken ;  
      dispatch_once(&onceToken, ^{  
      _instance = [[self alloc] init] ;  
      }) ;   
     return _instance ;  
  } 
  

• Swift

  final class Singleton {
     private init() { }
     static let shared = Singleton()
  }
  

5. 獲取字典中的鍵、值

• OC

  NSDictionary *dictionary = [@"key": @"value"];
  NSArray *keys = dictionary.allKeys;
  

• Swift

  let dictionary = ["key": "value"]
  let keys = Array(dictionary.keys)  // 這里 dictionary.keys 不再是數(shù)組，需要再轉(zhuǎn)換
  

未完待續(xù)，歡迎補(bǔ)充