Question

当我的应用程序第一次启动时，我正在展示4个UIViewController的教程。每个UIViewController都有一个带有segue的Button，呈现下一个ViewController。最后一个ViewController有一个按钮＆＃34;让我们开始＆＃34;这应该完全取消教程。

问题： 它解除了除第一个之外的所有ViewControllers。我不明白为什么？！

我的期望：

在最后一个ViewController4上我调用了第一个ViewController的dismissIntroduction（）函数，所以我除了所有ViewControllers（包含ViewController1）之外都应该消失。当我在第一个ViewController上放一个按钮并调用函数＆＃34; dismissIntroduction（）＆＃34;它消失了。

ViewController 1（WelcomeViewController）：

protocol WelcomeViewDelegate {
    func dismissIntroduction()
}

class WelcomeViewController: UIViewController, WelcomeViewDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    func dismissIntroduction() {
        self.dismissViewControllerAnimated(true, completion: nil)
    }


    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        let destination = segue.destinationViewController as! ViewController2
        destination.delegate = self
    }

}

ViewController 2：

class ViewController2: UIViewController {

    var delegate:WelcomeViewDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }        

    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        let destination = segue.destinationViewController as! ViewController3
        destination.delegate = self.delegate
    }

}

ViewController 3：

class ViewController3: UIViewController {

    var delegate:WelcomeViewDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }        

    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        let destination = segue.destinationViewController as! ViewController4
        destination.delegate = self.delegate
    }

}

ViewController4（最后一个）：

class ViewController4: UIViewController {

    var delegate:WelcomeViewDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func pressLetsStart(sender: AnyObject) {
        self.delegate!.dismissIntroduction()
    }

}

编辑： 当我把dismissViewControllerAnimated函数放两次时，我得到了它的工作！？

func dismissIntroduction() {
    self.dismissViewControllerAnimated(true, completion: nil)
    self.dismissViewControllerAnimated(true, completion: nil)
}

但为什么呢？我不明白背后的逻辑......

Answer 1

您正在寻找解决问题的错误方法，您需要做的是寻找Unwind Segues。完成本教程：https://spin.atomicobject.com/2014/10/25/ios-unwind-segues/

Answer 2

我现在用最后一个ViewController中的以下函数解决了这个问题：

@IBAction func pressLetsStart(sender: AnyObject) {
    self.dismissModalStack()
}

private func dismissModalStack() {
    var vc = self.presentingViewController! as UIViewController
    while (vc.presentingViewController != nil) {
        vc = vc.presentingViewController!;
    }
    vc.dismissViewControllerAnimated(true, completion: nil)
}

在带有委托的多个UIViewControllers的队列上使用dismissViewController

2 个答案: