Question

例如，我有一个BaseObject类：

class BaseObject: NSObject {
    let id:UInt64
}

此对象的经理类：

public class Manager: NSObject {
    public var objs:[BaseObject] = []

    public func addObj(obj:BaseObject) {
        ...
    }
}

我想创建一个库，并允许开发人员设置自己的类，该类应继承自Base Object

例如：

class MyOwnBaseObject: BaseObject {
   var ownProperty:Int = 0
}

var manager = Manager();
manager.objClass = MyOwnBaseObject

和manager.objs现在应该返回：[MyOwnBaseObject]和manager.addObj()应该与MyOwnBaseObject

一起使用

这可能吗？

Answer 1

如果希望返回类型属于您指定的子类，则可以使用泛型：

public class BaseObject: NSObject {
    let id:UInt64 = 0
}

public class MyOwnBaseObject: BaseObject {
    var ownProperty:Int = 0
}

public class Manager<T>: NSObject {
    public var objs:[T] = []

    public func addObj(obj:T) {
        objs.append(obj)
    }
}

var manager = Manager<BaseObject>()
let ob1 = BaseObject()
manager.addObj(obj: ob1)
let ob2 = BaseObject()
manager.addObj(obj: ob2)

var otherManager = Manager<MyOwnBaseObject>()
let ownOb1 = MyOwnBaseObject()
otherManager.addObj(obj: ownOb1)
let ownOb2 = MyOwnBaseObject()
otherManager.addObj(obj: ownOb2)


print(manager.objs)    // objs is of type [BaseObject]
print(otherManager.objs)   // objs is of type [MyOwnBaseObject]

如果没有泛型，您的代码仍然有效，但您需要将objs返回的任何对象强制转换为自定义类（例如MyOwnBaseObject）以访问任何特定于子类的属性。

为对象Swift定义自定义类

1 个答案: