创建具有从超类继承的值的字典

Question

我有多个从单个类继承的类，是否可以为它们创建字典映射？因此，在给定字符串键的情况下，我可以引用正确的类。

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

GoogleView和DuckDuckGoView都是EngineView的子类，但是XCode抱怨：

“无法将类型“ GoogleView.Type”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，您可以执行以下操作：

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

用法

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