使用从超类继承的值创建字典

Question

>我有多个类继承自单个类，是否可以为它们创建字典映射？所以我可以在给定字符串键的情况下引用正确的类。

let map = [String: EngineView] = [
  "google": GoogleView,
  "duckduckgo": DuckDuckGoView
]

GoogleView和DuckDuckGoView都是EngineView子类，但XCode抱怨：

"无法将'GoogleView.Type'类型的值转换为预期的字典值类型'EngineView'">

Answer 1

假设GoogleView和DuckDuckGoView继承自EngineView，你可以做这样的事情：

let map = [String: EngineView.Type] = [
  "google": GoogleView.self,
  "duckduckgo": DuckDuckGoView.self
]

用法

if let aClass = map["google"] {
    let instance = aClass.init()
}