URL is always nil in Swift 3

问题:

I have a struct that I am using to call out to the iTunes API. But when ever I run it myURL variable is never getting set, it's always nil. Not sure what I am doing wrong:

let myDefaultSession = URLSession(configuration: .default) var myURL: URL? var myDataTask: URLSessionTask?  struct APIManager {      func getJSON(strURL: String)  {         myURL = URL(string: strURL)         var dictReturn: Dictionary<String, Any> = [:]          //cancel data task if it is running         myDataTask?.cancel()         print(myURL!) //<----Always nil     } } 

Here's the string:

"https://itunes.apple.com/search?media=music&entity=song&term=The Chain" 

回答1:

nil because the URL contains a space. You need to encode the string first and then convert it to an URL.

func getJSON(strURL: String)  {     if let encoded = strURL.addingPercentEncoding(withAllowedCharacters: .urlFragmentAllowed),         let myURL = URL(string: encoded) {        print(myURL)     }      var dictReturn:Dictionary<String, Any> = [:]      //cancel data task if it is running     myDataTask?.cancel() } 

URL will be:

https://itunes.apple.com/search?media=music&entity=song&term=The%20Chain 

文章来源: URL is always nil in Swift 3