Question

如果我声明了一个带有ViewDidLoad()的变量。有没有办法在ViewDidLoad( )之外访问该变量？

我已经从API检索并存储了JSON数据。我可以在ViewDidLoad( )中访问变量'hourlyInfo'，但不能访问它之外的变量'hourlyInfo'。我应该使用全局变量吗？或者我是否在开始时错误地解决了这个问题？

eoverride func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    //getting the data from URL:
    let mainAddress = NSURL(string: "https:.......") 


    //Now, getting the data syncronously by creating a session object::
    let sharedSession = NSURLSession.sharedSession()
    let downloadTask: NSURLSessionDownloadTask =
    sharedSession.downloadTaskWithURL(mainAddress!, completionHandler: {
        (location:NSURL!, response:NSURLResponse!, error: NSError!) -> Void in

        if error == nil {
            //Now, creating a dataObject for the task:
            let dataObject = NSData(contentsOfURL: location)


            //getting a formated dictionary of the data from URL:
            var weatherDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(dataObject!, options: nil, error: nil) as NSDictionary //added '!' to NSdata for now





   var hourlyInfo = hourlyData(weatherDictionary: weatherDictionary) 

   println(hourlyInfo.hourPop1)//testing                         


        }



    })

    downloadTask.resume()

Answer 1

由于您在viewDidLoad内创建了hourlyInfo，因此只能在viewDidLoad内使用，更具体地说，downloadTaskWithURL块。您可以在类的顶部创建一个属性来保存hourlyInfo，但只有在块完成时才会设置hourlyInfo。此外，由于您将使用属性并在块内引用self.hourlyInfo，您应该创建一个弱自变量，如下所述：How to Correctly handle Weak Self in Swift Blocks with Arguments。

如何在ViewDidLoad（）之外使用变量 - Swift

1 个答案: