ios - 不能对类型为 'Any' SWIFT 的非可选值使用可选链接

Question

我对 Swift 非常陌生，我在构建一个天气应用程序时遇到了问题，该应用程序利用了来自名为 openweathermap.org 的网站的 API。当用户输入一个城市并单击“提交”时，他们应该能够看到一个显示天气描述的标签。

JSON 格式的结果是:

(
        {
        description = haze;
        icon = 50d;
        id = 721;
        main = Haze;
    },
        {
        description = mist;
        icon = 50d;
        id = 701;
        main = Mist;
    }
)

在尝试调试时，我使用了代码:print(jsonResult["weather"]!) 这让我可以看到上面的 JSON 详细信息。但是，当我尝试获取天气描述时，我似乎无法让它工作。

我的目标:我试图让天气描述显示在我的应用程序上。我目前收到错误:无法对“任何”类型的非可选值使用可选链接。非常感谢您的帮助!

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var cityTextField: UITextField!

    @IBOutlet weak var resultLabel: UILabel!


    @IBAction func submit(_ sender: AnyObject) {
        // getting a url
        if let url = URL(string: "http://api.openweathermap.org/data/2.5/weather?q=" + (cityTextField.text?.replacingOccurrences(of: " ", with: "%20"))! + ",uk&appid=08b5523cb95dde0e2f68845a635f14db") {

        // creating a task from the url to get the content of that url
        let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
            if error != nil {
                print("error")
            } else {
                print("no error")
                if let urlContent = data {
                    do {
                        let jsonResult = try JSONSerialization.jsonObject(with: urlContent, options: JSONSerialization.ReadingOptions.mutableContainers) as! [String:Any]
                        //print(jsonResult["weather"]!)
                        if let description = jsonResult["weather"]??[0]["description"] as? String {
                            DispatchQueue.main.sync(execute:{
                                self.resultLabel.text = description
                            })
                        }
                    } catch {
                        print("JSON processing failed")
                    }
                }
            }
        }
        task.resume()
        } else {
            resultLabel.text = "Couldn't find weather for that city. Please try a different city."
        }
    }
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    }

Answer 1

试试这个

let jsonResult = try JSONSerialization.jsonObject(with: urlContent, options: JSONSerialization.ReadingOptions.mutableContainers) as! [String:Any]


    let weather = jsonResult["weather"] as! [[String : Any]]
    if let description = weather[0]["description"] as? String {

        print(description)
    }