Question

我正在尝试从updateProgress对象调用函数LoadingDataHelper，但我的代理没有被调用。我认为问题在于LoadingDataHelper与LoadingDataViewController没有关联（我的意思是，当您拥有UIView和viewController时。

LoadingDataHelper

protocol LoadingNewDataDelegate: class {
    func updateProgress(progress : Float)
}

class LoadingDataHelper: NSObject {
    var delegate: LoadingNewDataDelegate?
    static let shared = LoadingDataHelper() // shared instance

    func loginUser() {
    //more code
        updateProgressInViewController()
    //more code
    }

    func updateProgressInViewController() {
        delegate?.updateProgress(0.3)
    }

}

LoadingDataViewController

class LoadingDataViewController: UIViewController, LoadingNewDataDelegate {

let loadingDataHelper: LoadingDataHelper = LoadingDataHelper()

    override func viewDidLoad() {
        super.viewDidLoad()
        loadingDataHelper.delegate = self
    }

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)

        if (NSUserDefaults.standardUserDefaults().boolForKey("approvedTermsOfUse")) {
            self.updateProgress(0.1)
            LoadingDataHelper.shared.loginUser()
        } else {
            self.askForTerms()
        }
    }

    func updateProgress(progress : Float) {
        self.progressBar.setProgress(progress, animated: true)
        self.progressBar.setNeedsDisplay()
    }
}

有没有办法解决这个问题？

Answer 1

上面的代码有一些错误：在LoadingDataViewController中，您要为 LoadingDataHelper 类创建静态属性，并将委托设置为该类。但是你用直接电话叫“loginUser”。

您需要更改如下：

class LoadingDataViewController: UIViewController, LoadingNewDataDelegate {    
**//Change to shared initialisation of object//**
let loadingDataHelper: LoadingDataHelper = LoadingDataHelper.shared

    override func viewDidLoad() {
        super.viewDidLoad()
        loadingDataHelper.delegate = self
    }

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)

        if (NSUserDefaults.standardUserDefaults().boolForKey("approvedTermsOfUse")) {
            self.updateProgress(0.1)
           **//Call using static object instead of new instance or direct call//**
            loadingDataHelper.loginUser()
        } else {
            self.askForTerms()
        }
    }

    func updateProgress(progress : Float) {
        self.progressBar.setProgress(progress, animated: true)
        self.progressBar.setNeedsDisplay()
    }
}

这将使您的控制器获得委托回电。

Swift - 未调用其他视图控制器中的函数（协议/委托）

1 个答案: