对于子类NSCoding和NSObject的自定义类，未调用Equatable类型的==函数 [英] Overridden == function for Equatable type not called for custom class that subclasses NSCoding and NSObject

问题描述

下面的FooBar类必须覆盖Equatable类型的==函数.

The FooBar class below has to override the == function of the Equatable type.

但是，在FooBar对象的数组上调用contains不会导致调用自定义==函数内部的断点.可能有另一个==函数覆盖此自定义函数吗?

However, calling contains on an array of FooBar objects does not cause a breakpoint inside the custom == function to get invoked. Is it possible another == function is overriding this custom one?

注意:因为FooBar必须是NSCoding和NSObject的子类，所以FooBar不会将Equatable列为协议，因为它会导致此错误:

Note: Because FooBar must subclass from NSCoding and NSObject, FooBar does not list Equatable as a protocol because it causes this error:

'FooBar'与协议'Equatable'的冗余一致性

Redundant conformance of 'FooBar' to protocol 'Equatable'

func ==(lhs: FooBar, rhs: FooBar) -> Bool {
    return lhs.id == rhs.id
}

class FooBar: NSObject, NSCoding {
     // Class def
}

// Both serverFooBars and gFooBars are [FooBar]
let newFooBars = serverFooBars.filter { !gFooBars.contains($0) }

推荐答案

由于您的类继承自NSObject，因此您无需使用swift协议Equatable，而必须覆盖NSObject方法isEquals:

Because your class inherits from NSObject you do not need to use the swift protocol Equatable instead you must override the NSObject method isEquals:

Swift 3.x

class FooBar: NSObject, NSCoding {
  override func isEqual(_ object: Any?) -> Bool {
    return id == (object as? FooBar)?.id
  }
}

(感谢堪察加半岛)

Swift 2.x

class FooBar: NSObject, NSCoding {
  override func isEqual(object: AnyObject?) -> Bool {
    return id == (object as? FooBar)?.id
  }
}

这篇关于对于子类NSCoding和NSObject的自定义类，未调用Equatable类型的==函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！