为什么数组是Swift中的AnyObject？

I'm having trouble understanding the limitations of AnyObject.

我无法理解AnyObject的局限性。

You can see from the header that Array is a struct. Nevertheless, this code works:

您可以从标题中看到Array是一个结构体。不过,这段代码有效:

var whatobject : AnyObject
whatobject = [1,2]

And it's not just literal arrays:

它不仅仅是文字数组:

var whatobject : AnyObject
let arr = [1,2,3]
whatobject = arr

However, I can't assign a struct that I make to whatobject:

但是,我无法为whatobject分配一个结构:

struct S {}
var whatobject : AnyObject
whatobject = S() // error

So an array isn't really a struct after all?

那么数组毕竟不是一个真正的结构?

1 个解决方案

#1

that's the fun part when bridging comes in...

当桥接进来时,这是有趣的部分......

by default, Swift bridge

默认情况下,Swift桥

Int (and friends) to NSNumber

Int(和朋友)到NSNumber

String to NSString

字符串到NSString

Dictionary to NSDictionary

字典到NSDictionary

so compiler will change them to object if need to

所以如果需要,编译器会将它们更改为对象

and you can do

你可以做到

var num : AnyObject = 1 // I think num is now NSNumber
var arr : AnyObject = [1,2,3] // I think arr is now NSArray of @[@1,@2,@3]

and you can't assign sturct/enum to AnyObject because they are not object type (you can use Any to hold them)

并且您不能将sturct / enum分配给AnyObject,因为它们不是对象类型(您可以使用Any来保存它们)

#1