Swift枚举类型

1.基本枚举类型定义：

enum BookOrientationType: Int {
    case portrait
    case landscape
}

• 这是比较常用的枚举类型定义，适用于大部分场景。但是枚举类型中的值除了一部分公共的参数外，可能还含有独有的元素、属性。而我们希望能够通过一个公共的方法实现不同枚举类型class的创建，这时候可以定义带参数的枚举类型。

2.带参数的枚举类型定义：

//定义
public enum HUDContentType {
    case success
    case error
    case progress
    case image(UIImage?)
    case rotatingImage(UIImage?)

    case labeledSuccess(title: String?, subtitle: String?)
    case labeledError(title: String?, subtitle: String?)
    case labeledProgress(title: String?, subtitle: String?)
    case labeledImage(image: UIImage?, title: String?, subtitle: String?)
    case labeledRotatingImage(image: UIImage?, title: String?, subtitle: String?)

    case label(String?)
    case systemActivity
}

//使用
switch content {
        case .success:
            return PKHUDSuccessView()
        case .error:
            return PKHUDErrorView()
        case .progress:
            return PKHUDProgressView()
        case let .image(image):
            return PKHUDSquareBaseView(image: image)
        case let .rotatingImage(image):
            return PKHUDRotatingImageView(image: image)

        case let .labeledSuccess(title, subtitle):
            return PKHUDSuccessView(title: title, subtitle: subtitle)
        case let .labeledError(title, subtitle):
            return PKHUDErrorView(title: title, subtitle: subtitle)
        case let .labeledProgress(title, subtitle):
            return PKHUDProgressView(title: title, subtitle: subtitle)
        case let .labeledImage(image, title, subtitle):
            return PKHUDSquareBaseView(image: image, title: title, subtitle: subtitle)
        case let .labeledRotatingImage(image, title, subtitle):
            return PKHUDRotatingImageView(image: image, title: title, subtitle: subtitle)

        case let .label(text):
            return PKHUDTextView(text: text)
        case .systemActivity:
            return PKHUDSystemActivityIndicatorView()
        }