Swift 2.0中的JSON解析错误

Kamikasse 发表于 Dev

卡米卡斯

我正在学习在Swift 2.0中进行编码，并且在将其编译到模拟器时陷入了困境。该self.setLabels（！数据）行显示的信息主题1：EXC_BAD_INSTRUCTION。谁能帮我这个？我正在尝试一种试错法，但还没有运气...

 lass ViewController: UIViewController {

@IBOutlet weak var cityNameTextField: UITextField!
@IBOutlet weak var cityNameLabel: UILabel!
@IBOutlet weak var cityTempLabel: UILabel!

@IBAction func getWeatherDataClick(sender: AnyObject)  {
    getWeatherData("http://api.openweathermap.org/data/2.5/weather?q=" + cityNameTextField.text! + "")
}

override func viewDidLoad() {
    super.viewDidLoad()
    getWeatherData("http://api.openweathermap.org/data/2.5/weather?q=London,uk&appid=2de143494c0b295cca9337e1e96b00e0")
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func getWeatherData(urlString: String) {
let url = NSURL(string: urlString)
let task = NSURLSession.sharedSession().dataTaskWithURL(url!) { (data, response, error) in
    dispatch_async(dispatch_get_main_queue(), {
        self.setLabels(data!)

    })

    }
    task.resume()
}

func setLabels(weatherData: NSData) {
    let jsonResult = AnyObject? ()
    do {
        if let jsonResult = try NSJSONSerialization.JSONObjectWithData(weatherData, options: []) as? NSDictionary {
        print(jsonResult)
        }
    } catch {
            print(error)
        }
    if let name = jsonResult!["name"] as? String {
    cityNameLabel.text = name
    }
if let main = jsonResult!["main"] as? NSDictionary {
    if let temp = main["temp"] as? Double {
        cityTempLabel.text = String(format: "%.1f", temp)
        }
    }
};

}

火炬

首先猜测是：data == nil。您的函数：setLabels:不准备接收nil参数。尝试将此函数的声明更改为：

func setLabels(weatherData: NSData?)

甚至更好地在您的代码块中data == nil调用之前处理可能性：setLabelsNSURLSession

if let weatherData = data as? NSData {
    //your data is not nil
    //you can securely call setLabels
    self.setLabels(weatherData)
} else {
   //ooops sth goes wrong your data is nil, try to figure out why
}

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