将字符串转换为 NSURL 在 swift 中是 return nil

Question

我正在尝试将 String 转换为 NSURL，我的代码如下：

var url = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=\(self.latitude),\(self.longitude)&destinations=\(self.stringForDistance)&language=en-US"
    println("This is String: \(url)")
    var remoteUrl : NSURL? = NSURL(string: url)
    println("This is URL: \(remoteUrl)")

并且控制台打印如下内容：

This is String: https://maps.googleapis.com/maps/api/distancematrix/json?origins=-34.4232722,150.8865837&destinations=-34.4250728,150.89314939999997|-34.4356434,150.8858692|-34.4250728,150.89314939999997|-34.4356434,150.8858692|-34.4250728,150.89314939999997|-34.4356434,150.8858692|-34.423234,150.88658899999996|-34.423234,150.88658899999996|-34.428251,150.899673|-34.4257439,150.89870229999997|-34.423234,150.88658899999996|-34.4257439,150.89870229999997|-34.425376,150.89388299999996&language=en-US

This is URL: nil

remoteUrl是nil，我不知道这里有什么问题。

之后，我尝试像这样对 String 进行排序：

var url : String = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=-34.4232722,150.8865837&destinations=-34.4250728,150.89314939999997&language=en-US"
    println("This is String: \(url)")
    var remoteUrl : NSURL? = NSURL(string: url)
    println("This is URL: \(remoteUrl)")

并且控制台打印：

This is String: https://maps.googleapis.com/maps/api/distancematrix/json?origins=-34.4232722,150.8865837&destinations=-34.4250728,150.89314939999997&language=en-US
This is URL: Optional(https://maps.googleapis.com/maps/api/distancematrix/json?origins=-34.4232722,150.8865837&destinations=-34.4250728,150.89314939999997&language=en-US)

这工作正常。

所以谁能告诉我第一个案例有什么问题吗？

Answer 1

按照 Martin R 的建议，我看到了 THIS post 并且我将 objective-c 代码转换为 swift 并且我得到了这个代码：

var url : NSString = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=\(self.latitud‌e),\(self.longitude)&destinations=\(self.stringForDistance)&language=en-US" 
var urlStr : NSString = url.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)! 
var searchURL : NSURL = NSURL(string: urlStr)! 
println(searchURL)

这一切正常。

对于 swift 3.0:

let url : NSString = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=\(self.latitud‌e),\(self.longitude)&destinations=\(self.stringForDistance)&language=en-US"
let urlStr : NSString = url.addingPercentEscapes(using: String.Encoding.utf8.rawValue)! as NSString
let searchURL : NSURL = NSURL(string: urlStr as String)!
print(searchURL)

Answer 2

我认为试试这个对我来说非常有用

  var url : String = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=-34.4232722,150.8865837&destinations=-34.4250728,150.89314939999997&language=en-US"
        println("This is String: \(url)")
        var urlStr : NSString = url.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!
        var remoteUrl : NSURL? = NSURL(string: url)
        println("This is URL: \(remoteUrl!)")

Answer 3

如果 NSURL 为 null 并尝试通过 Web 视图加载 http URL，您可能会收到以下错误：

fatal error: unexpectedly found nil while unwrapping an Optional value

为了安全起见，我们应该使用：

 var urlStr = strLink!.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)

if var url = NSURL(string: urlStr!){
    println(self.strLink!)

    self.webView!.loadRequest(NSURLRequest(URL: url))

}

Answer 4

正如 blwinters 所说，在 Swift 3.0 中使用

URL(string: urlPath.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!)

Answer 5

SWIFT 3.0

修复转换为 NSURL 的错误字符串的安全方法是使用 "guard let"

展开 urlPath 字符串变量

guard let url = NSURL(string: urlPath.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!)
            else
            {
                print("Couldn't parse myURL = \(urlPath)")
                return
            }

在我上面的示例中名为 "urlPath" 的变量将是您已经在代码中的其他地方声明的 url 字符串。

我遇到了这个答案，因为在我的字符串被制成 NSURL 时，我随机收到 XCode 中断的 nil 错误。没有逻辑为什么它是随机的，即使我打印 url 它们看起来很好。一旦我添加了 .addingPercentEncoding，它就会恢复正常，没有任何问题。

tl;dr 对于阅读本文的任何人，请尝试我上面的代码并将 "urlPath" 换成您自己的本地字符串 url.

Answer 6

这对我有用

let url : NSString = MyUrls.baseUrl + self.url_file_open as NSString
let urlStr : NSString = url.addingPercentEscapes(using: String.Encoding.utf8.rawValue)! as NSString
if let url = URL(string: urlStr as String) {
    let request = URLRequest(url: url)
    self.businessPlanView.loadRequest(request)
}

将字符串转换为 NSURL 在 swift 中是 return nil

Convert String to NSURL is return nil in swift

string

nsurl

ios

swift