ios - 界面标签!没有正确更新

Question

我的 self.message.text = (newContentArray[0] as!String) 不允许我打印到我的标签。我的标签连接正确，但没有加载我的数据。

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var city: UITextField!
    @IBOutlet weak var message: UILabel!

    @IBAction func buttonPressed(sender: AnyObject) {

        self.view.endEditing(true)

        var urlString = "http://www.weather-forecast.com/locations/" + city.text.stringByReplacingOccurrencesOfString(" ", withString: "") + "/forecasts/latest"

        var url = NSURL(string: urlString)

        let task = NSURLSession.sharedSession().dataTaskWithURL(url!){(data, response, error) in

            var urlContent = NSString(data: data, encoding: NSUTF8StringEncoding) 
            var contentArray  = urlContent!.componentsSeparatedByString("<span class=\"phrase\">")
            var newContentArray = contentArray[1].componentsSeparatedByString("</span>")

            self.message.text = (newContentArray[0] as! String)

        }
        task.resume()
    }

Answer 1

您应该在主线程上更新您的用户界面。在响应 block 中添加:

dispatch_async(dispatch_get_main_queue(),{ 
    var urlContent = NSString(data: data, encoding: NSUTF8StringEncoding)       
    var contentArray = urlContent!.componentsSeparatedByString("<span class=\"phrase\">") 
    var newContentArray = contentArray[1].componentsSeparatedByString("</span>") 
    self.message.text = (newContentArray[0] as! String) 
})