ios 如何将 swift Dictionary 转换为 NSDictionary
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How do I convert swift Dictionary to NSDictionary
提问by BergP
I'm trying to convert a [String : String](a Swift Dictionary) to NSDictionary, for later use on a JSON library that produces a string
我正在尝试将[String : String](a Swift Dictionary)转换为NSDictionary，以便以后在生成字符串的 JSON 库上使用
var parcelDict = ["trackingNumber" : parcel.number,
"dstCountry" : parcel.countryCode];
if (parcel.postalService != nil)
{
parcelDict["postalService"] = parcel.postalService;
}
var errorPtr: NSErrorPointer
let dict: NSDictionary = parcelDict
var data = NSJSONSerialization.dataWithJSONObject(dict, options:0, error: errorPtr) as NSData
return NSString(data: data, encoding: NSUTF8StringEncoding)
but let dict: NSDictionary = parcelDictdoes not work
但let dict: NSDictionary = parcelDict不起作用
let dict: NSDictionary = parcelDict as NSDictionary
var data = NSJSONSerialization.dataWithJSONObject(parcelDict as NSMutableDictionary, options:0, error: errorPtr) as NSData
All of these examples do not work. They produce the following errors:
所有这些示例都不起作用。它们产生以下错误：
What's the correct way of doing it?
正确的做法是什么？
Update:
更新：
Code that works
有效的代码
var parcelDict = ["trackingNumber" : parcel.number!,
"dstCountry" : parcel.countryCode!];
if (parcel.postalService != nil) {
parcelDict["postalService"] = parcel.postalService;
}
var jsonError : NSError?
let dict = parcelDict as NSDictionary
var data = NSJSONSerialization.dataWithJSONObject(dict, options:nil, error: &jsonError)
return NSString(data: data!, encoding: NSUTF8StringEncoding)!
回答by Arbitur
You have to cast it like this:
你必须像这样投射它：
let dict = parcelDict as NSDictionary
Otherwise the Swift Dictionary and NSDictionary are treated almost the same way when using it in methods for ex:
否则，在方法中使用 Swift Dictionary 和 NSDictionary 时，它们的处理方式几乎相同：
func test(dict: NSDictionary) {}
let dict = ["Test":1]
test(dict)
Will work completely fine.
将完全正常工作。
After your update
更新后
If you change your Dictionary value type to non optional String then your error will go away.
如果您将 Dictionary 值类型更改为非可选字符串，那么您的错误就会消失。
[String:String?] change to -> [String:String]
回答by Gopal Devra
You can use this easy method
你可以使用这个简单的方法
let dictSwift = ["key1": "value1", "key1": value2]
let dictNSMutable = NSMutableDictionary(dictionary: dictSwift)
Enjoy coding!
享受编码！
回答by ABakerSmith
Don't don't need to convert it to an NSDictionary. Just use:
不需要将其转换为NSDictionary. 只需使用：
var data = NSJSONSerialization.dataWithJSONObject(parcelDict, options:0, error: errorPtr) as NSData
It's mentioned in this post: Making a JSON object in Swift
在这篇文章中提到：在 Swift 中制作一个 JSON 对象
Edit
编辑
From your screenshots I believe your problem lies in the value type in your parcelDictDictionary. I can recreate the error with the following code:
从你的截图我相信你的问题在于你的parcelDict字典中的值类型。我可以使用以下代码重新创建错误：
let dict = [String: String?]()
let nsDict = dict as NSDictionary // [String: String?] is not convertible to NSDictionary
However, using a Stringinstead of a String?as the value type removes the error.
但是，使用 aString而不是 aString?作为值类型可以消除错误。
Therefore, when populating parcelDictperhaps you should only add to it values which are not nil.
因此，在填充时，parcelDict您可能应该只向它添加不是nil.
