objective-c - Swift 1.2 为什么我不能继承任何 NSCell 的子类？

Question

为什么我不能继承 NSCell 的任何子类？ 我想子类化 MyButtonCell，即 CustomButtonCell: NSButtonCell。含义

class MyCustomButtonCell: MyButtonCell { }

总是给我以下错误:

<unknown>:0: error: declaration has a different @objc name from the declaration it overrides ('initTextCell:' vs. 'initWithTextCell:')
Custom_Controls.MyButtonCell:9:24: note: overridden declaration is here
  @objc @objc override init(textCell aString: String)
                       ^
<unknown>:0: error: declaration has a different @objc name from the declaration it overrides ('initImageCell:' vs. 'initWithImageCell:')
Custom_Controls.MyButtonCell:10:24: note: overridden declaration is here
  @objc @objc override init(imageCell image: NSImage?)
                       ^

重现我的问题的简单步骤:

1. 打开终端

2. 类型:swift(如果您有最新的 Xcode 6.3.1)

3. 当你得到时，

   Welcome to Swift version 1.2. Type :help for assistance.

输入以下内容:

1> import AppKit
2> class Foo : NSCell {}
3> class Bar : Foo {} 

您将收到以下错误:

declaration has a different @objc name from the declaration it overrides ('initTextCell:' vs. 'initWithTextCell:')__lldb_expr_9.Foo:3:24: note: overridden declaration is here @objc @objc override init(textCell aString: String) ^ declaration has a different @objc name from the declaration it overrides ('initImageCell:' vs. 'initWithImageCell:')__lldb_expr_9.Foo:4:24: note: overridden declaration is here @objc @objc override init(imageCell image: NSImage?) ^

为什么？有办法解决这个问题吗？

仅供引用:Swift 1.1 没有这个问题!

Answer 1

看来添加一个符合 NSCoding 的 init 方法可以消除错误:

import AppKit
class Foo : NSCell {
    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}
class Bar : Foo {}