ios - 如何为 pageControl.currentPage 创建枚举？

Question

我想使用返回整数的 pageControl.currentPage 来跟踪我的页面。我的 switch 语句是这样设置的:

let currentPage = pageControl.currentPage
switch currentPage {
case 0:

// execute code for first page 

case 1:

// execute code for second page 

case 2:

// execute code for third page 

default: break
}

而不是大小写“0”、“1”和“2”，我想更语义化，例如

case FirstPage:
case SecondPage:
case ThirdPage:

我该怎么做呢？

Answer 1

最好的选择是用 Int 值支持枚举。

你可以像这样声明你的枚举:

enum PageEnum: Int {
  case firstPage = 0  // Implicitly 0 if you don't set value for first enum.
  case secondPage = 1 // Each enum after will automatically increase by 1
  case thirdPage = 2  // so explicitly listing raw value is not necessary.
}

然后您可以使用一个开关来确定页面值，如下所示:

switch PageEnum(rawValue: currentPage)! {
  case .firstPage:
    print("You're on the first page")
  case .secondPage:
    print("You're on the second page")
  case .thirdPage:
    print("You're on the third page")
  default:
    assert(false, "You shouldn't ever land here")
}