Question

我是iOS和编程菜鸟，所以我为任何不好的措辞或错误道歉。

我正在为我的应用程序的API解析引号，每次单击UIButton时，它都会在textLabel上显示它。为了防止字符串脱离textLabel或调整为不可读的字体，如果字符串字符数太高，我试图通过调用我的NSObject中的函数来请求新的引号。我设置了一个NSObject进行重新获取，但每当我尝试将字符串重新分配给NSObject的textLabel.text或尝试将字符串发送回ViewController时，qouteLabel.text将返回nil

这是我的viewcontroller，我在这里提出了报价的初始请求

    import UIKit
import Alamofire

class RSQuotesViewController: RSViewController {


    var ronImageView: UIImageView!
    var quoteLabel = UILabel!()


    override func loadView() {
        let frame = UIScreen.mainScreen().bounds
        let view = UIView(frame: frame)
        view.backgroundColor = UIColor.grayColor()



        ronImageView = UIImageView(frame: CGRectMake(frame.width/2-160, frame.height-600, 320, 600))
        let ron = "ron.png"
        let ronImage = UIImage(named: ron)
        ronImageView.image = ronImage
        view.addSubview(ronImageView);

        let labelWidth = ronImageView.frame.width/2
        let quoteLabelX = labelWidth-40

        quoteLabel = UILabel(frame: CGRect(x: quoteLabelX, y: ronImageView.frame.height/4+15, width: labelWidth, height: 160))
        quoteLabel.textAlignment = .Center
        quoteLabel.text = "Click to Start"
        quoteLabel.shadowColor = UIColor.grayColor()
        quoteLabel.adjustsFontSizeToFitWidth = true
        quoteLabel.lineBreakMode = .ByWordWrapping // or NSLineBreakMode.ByWordWrapping
        quoteLabel.numberOfLines = 0
        view.addSubview(quoteLabel)


        self.view = view
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        let frame = UIScreen.mainScreen().bounds

        let getQuote = UIButton(frame: CGRect(x: 0, y: 0, width: frame.size.width+50, height: frame.size.height))
        getQuote.backgroundColor = UIColor.clearColor()
        getQuote.setTitle("", forState: UIControlState.Normal)
        getQuote.addTarget(self, action: #selector(RSQuotesViewController.getQuote(_:)), forControlEvents: UIControlEvents.TouchUpInside)

        self.view.addSubview(getQuote)

    }



    //  Gets quote when button is pressed
    func getQuote(sender: UIButton){
        let url = "http://ron-swanson-quotes.herokuapp.com/v2/quotes"
        Alamofire.request(.GET, url, parameters: nil).responseJSON { response in
            if let JSON = response.result.value as? Array<String>{
                let quoteDict = RSQoute()

                // if quote is too large get another one
                if (JSON[0].characters.count > 120){

                    print("greater than 120")
                    quoteDict.fetchQuote()

                } else {

                    self.quoteLabel.text = JSON[0]


                }





        }


    }

}

这是我的模型，我试图重新分配quoteLabel.text并获得nil

import UIKit
import Alamofire

class RSQoute: NSObject {

    var newQuote = String()


    //   fetchs new quote if quote is too large

    func fetchQuote(){

        let url = "http://ron-swanson-quotes.herokuapp.com/v2/quotes"
        Alamofire.request(.GET, url, parameters: nil).responseJSON { response in
            if let JSON = response.result.value as? Array<String>{
            self.newQuote = JSON[0]
                if (self.newQuote.characters.count > 120) {

                    print("Try Again: ---->\(self.newQuote)")
                    return self.fetchQuote()
                } else {
                    let quoteVC = RSQuotesViewController()
                    print("Retry was less than 120: ---->\(self.newQuote)")
                    print("quoteLabelText: ---->\(RSQuotesViewController().quoteLabel.text)")// comes back nil
                    RSQuotesViewController().quoteLabel.text = self.newQuote

                }




        }
    }
    }



}

如果我遗漏了某些内容或者尝试从API获取新报价的更简单/更好的方法，请告诉我们。）

Answer 1

在函数fetchQuote()中，将quoteVC设置为带有let quoteVC = RSQuotesViewController()的RSQuotesViewController（）的新实例。相反，您应该为quoteLabel.text的应用程序实例设置RSQuotesViewController()。您还提出了两个API请求。进入fetchQuote()的{{1}}功能，进入RSQuotesViewController的{{1}}功能

我认为你所寻找的将涉及闭包。试试fetchQuote()类

中的RSQuotes函数

fetchQuote()

然后，我会有一个RSQuotes函数func fetchQuote(completion: (result:String)){ let url = "http://ron-swanson-quotes.herokuapp.com/v2/quotes" Alamofire.request(.GET, url, parameters: nil).responseJSON { response in if let JSON = response.result.value as? Array<String>{ self.newQuote = JSON[0] if (self.newQuote.characters.count > 120) { print("Try Again: ---->\(self.newQuote)") completion(result: self.newQuote) } else { print("Retry was less than 120: ---->\(self.newQuote)") print("quoteLabelText: ---->\(RSQuotesViewController().quoteLabel.text)")// comes back nil completion(result: self.newQuote) } }，你可以做这样的事情

setQuote

我会看看一些与快速关闭有关的帖子，也可以查看。 http://goshdarnclosuresyntax.com/

另外，我不确定您是否打算在RSQuotesViewController课程中操纵quoteString。如果不是，func setQuote() { let quoteObj = RSQuote() quoteObj.fetchQuote() { result in quoteLabel.text = result } }可能更适合成为RSQuote。这样您就可以在不fetchQuote()初始化对象的情况下调用它。这就像static func

UIViewController中的textLabel.text在从NSObject

1 个答案: