swift小知识点之局部作用域do{}

　　OC里直接可以用{ }申明局部作用域，在swift里可以用 do { }

• OC中
  

  - (void)layoutSubviews {
      [super layoutSubviews]
      ///局部作用域
      {
          CGFloat X = 100.f;
          CGFloat Y = 150.f;
          CGFloat W = 200.f;
          CGFloat H = 100.f; 
         [self.removeBtn setFrame:CGRectMake(X, Y, W, H)];
      }
  }

• Swift中
  

  override func layoutSubviews() {
  　　super.layoutSubviews()
  //头像
     do {
        let X:CGFloat = 20.0
        let W:CGFloat = 40.0
        let H:CGFloat = 40.0
        let Y:CGFloat = (self.frame.height - H)
        iconImageView!.frame = CGRect(x: X, y: Y, width: W, height: H)
     }
  //标题
     do {
        let X:CGFloat = iconImageView!.frame.maxX + 10.0
        let Y:CGFloat = iconImageView!.frame.minY
        let W:CGFloat = 150.0
        let H:CGFloat = iconImageView!.frame.height
        titleLbl!.frame = CGRect(x: X, y: Y, width: W, height: H)
     }
  //日期
     do {
         let W:CGFloat = 100.0
         let H:CGFloat = iconImageView!.frame.height
         let X:CGFloat = self.frame.width - W - 20.0
         let Y:CGFloat = iconImageView!.frame.minY
         dateLbl!.frame = CGRect(x: X, y: Y, width: W, height: H)
     }
  }