迅速1.2覆盖NSManagedObject扩展中的prepareForDeletion

问题描述

在Swift 1.2中覆盖函数 prepareForDeletion 失败

Overriding the function prepareForDeletion fails in swift 1.2

// Playground - noun: a place where people can play

import UIKit
import CoreData

extension NSManagedObject {
    @objc func prepareForDeletion() {
        println("deleting object")
    }
}

@objc func prepareForDeletion() {
           ^

@objc func prepareForDeletion()

有人有主意吗?

谢谢罗恩

推荐答案

您不能覆盖同一类扩展中的类中的方法，这样做始终是未定义的行为.

You cannot override a method in a class in an extension of the same class, doing so was always undefined behaviour.

对于在Swift中覆盖Objective-C方法，在此未引起注意Xcode 6.2，现在可以在Xcode 6.3 beta中正确诊断.

For overriding Objective-C methods in Swift this went unnoticed inXcode 6.2 and is now properly diagnosed in Xcode 6.3 beta.

请注意，Objective-C中的相应做法–同一类的Objective-C扩展中的重写方法–也不允许，请参阅避免类别方法名称冲突" :

Note that the corresponding practice in Objective-C – overriding methods in an Objective-C extension of the same class – is also not allowed, see "Avoid Category Method Name Clashes":

您可以做的是在您的自定义方法中覆盖该方法 NSManagedObject 子类.

What you can do is to to override the method in your customNSManagedObject subclasses.

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