Swift 3 可选的麻烦.无法使用传入的字符串解开 url [英] Swift 3 Optional trouble. Can't unwrap url with passed in string

问题描述

我正在传入一个字符串变量以在 web 视图中打开一个 url，当我根据该字符串创建 url 时，它没有展开.我不确定我做错了什么.代码如下:

I am passing in a string variable to open a url in a webview and when I create the url based on the string its not unwrapping. I'm not sure what I'm doing wrong. Here is the code:

class WebViewController: UIViewController, WKUIDelegate {

var urlString:String?
var vehicle:Vehicle?
var theUrlString = "http://www.ksl.com/auto/search/" //This variable is set in the prepareForSegue in a previous view controller. It is set correctly

var webView: WKWebView!


override func loadView() {
    let webConfiguration = WKWebViewConfiguration()
    webView = WKWebView(frame: .zero, configuration: webConfiguration)
    webView.uiDelegate = self
    view = webView
    if let urlStri = urlString {
        print("url is " + urlStri)
        theUrlString = urlStri
    }else {

    }

}

override func viewDidLoad() {
    super.viewDidLoad()

    print("theUrlString is " + theUrlString) // this correctly prints: theUrlString is http://www.ksl.com/auto/search/index?keyword=&make%5B%5D=Chevrolet&model%5B%5D=Silverado 1500&yearFrom=2006&yearTo=2008&mileageFrom=&mileageTo=&priceFrom=&priceTo=&zip=&miles=25&newUsed%5B%5D=All&sellerType%5B%5D=&postedTime%5B%5D=&titleType%5B%5D=&body%5B%5D=&transmission%5B%5D=&cylinders%5B%5D=&liters%5B%5D=&fuel%5B%5D=&drive%5B%5D=&numberDoors%5B%5D=&exteriorCondition%5B%5D=&interiorCondition%5B%5D=&cx_navSource=hp_search
    if let url = URL(string: theUrlString){

        let myRequest = URLRequest(url: url) //In debugging, it never makes it inside the if statement here

        webView.load(myRequest)
    }


}

推荐答案

您的 theUrlString 未正确编码.因此，当您使用 URL(string:) 时，它返回 nil(表明传入的 URL 字符串格式错误).

Your theUrlString is not properly encoded. As a result, when you use URL(string:), it is returning nil (an indication that the URL string passed in was malformed).

我建议使用 URLComponents 来创建您的 URL.

I would recommend using URLComponents to create your URL.

类似于:

var urlComponents = URLComponents(string: "http://www.ksl.com/auto/search/index")

var arguments: [String: String] = [
    "keyword": "",
    "make": "Chevrolet",
    "model": "Silverado 1500"
]

var queryItems = [URLQueryItem]()

for (key, value) in arguments {
    queryItems.append(URLQueryItem(name: key, value: value))
}

urlComponents?.queryItems = queryItems

if let url = urlComponents?.url {
    print(url) // http://www.ksl.com/auto/search/index?keyword=&model=Silverado%201500&make=Chevrolet
}

URLComponents API 参考:https://developer.apple.com/reference/foundation/urlcomponents

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