Swift 3

Question

我有一个结构用于调用iTunes API。但是当我运行它时myURL变量永远不会被设置，它始终是nil。不确定我做错了什么：

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
    }
}

这里是字符串：

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

Answer 1

您获取nil，因为该网址包含空格。您需要先对字符串进行编码，然后将其转换为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()
}

网址为：

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