Swift 2.2打破了可选/解包可选 [英] Swift 2.2 breaks optionals/unwrapping optionals

问题描述

Swift 2.2几乎破坏了我所有的代码.甚至这个分配给标签的简单字符串也不再起作用:

Swift 2.2 has broken almost all my code. Even this simple string assigning to label doesn't work anymore:

cell.categoryName.text = peopleArray![indexPath.row]["Name"] as? String

错误显示为"从字符串"向下转换?！"到'String'仅解开可选内容，您是要使用'!!'吗?"

我现在要做什么更改.

编辑:

更多问题:

if (dict["data"]!["DataDetails"] as! NSArray).count == 0 {
}

由于这个原因，我遇到了分段错误，错误显示如下:警告:从字符串?！"强制转换无关类型"NSArray"总是失败

Due to this I am getting a segmentation fault and the error shows this: warning: cast from 'String?!' to unrelated type 'NSArray' always fails

更新:

我在我的课程中使用了NSDictionaries，NSArrays，这似乎引起了问题.将所有文字从Obj-C更改为swift，可使代码正常工作. 因此，我还将建议其他开发人员更喜欢快速文字.

I was using NSDictionaries, NSArrays in my classes that seems to cause the problem. Changing all the literals from Obj-C to swift made the code work properly. So, I will also recommend other developers to prefer swift literals.

推荐答案

使用swift类型和Objective-c NS ...类型似乎有些细微差异

it seems there are some slight differences when using the swift types and the objective-c NS... types

例如

let dic:NSDictionary? = ["a":"a"]

let str:NSString? = dic!["a"] as? NSString

let dic2:Dictionary? = ["b":"b"]

let str2:String? = dic2!["b"] //dont need to do any casting, already optional

print(str)
print(str2)

打印

Optional(a)
Optional("b")

因此，根据数组/字典的定义方式，您可能需要不同的转换/展开

so depending on how your array / dictionary is defined, you might need different casting/unwrapping

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