ios - 执行 segue 以查看选项卡和导航 Controller 后面的 Controller

Question

我在访问位于 TAB 和 NAV Controller 后面的 View Controller 时遇到问题。

我可以访问第一个 VC(见下面的代码)但我无法访问第四个 VC。

         SenderVC----->TabBarVC-⎜----NavVC----FirstVC
                                ⎜----NavVC----SecondVC
                                ⎜----NavVC----ThirdVC
                                ⎜----NavVC----FourthVC

我做错了什么？

如果有人能为我指出正确的方向，那就太好了。谢谢。

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    if (segue.identifier == "segueVC0") {
        let tabVC = segue.destination as! UITabBarController
        let navVC = tabVC.viewControllers![0] as! UINavigationController
        let destVC = navVC.viewControllers[0] as! FirstVC  // ==> this transition is working

    } else if (segue.identifier == "segueVC4") {
        let tabVC = segue.destination as! UITabBarController
        let navVC = tabVC.viewControllers![4] as! UINavigationController
        let destVC = navVC.viewControllers[0] as! FourthVC  // ==> this transition is NOT working !!!

    } else {
        print ("wrong segue ID")
    }
}

Answer 1

你好，我得到了第四个 VC 的实例

类 View Controller :UIViewController {

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

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func buttonTapped(sender: AnyObject) {
    print("ViewController - buttonTapped()")
    performSegue(withIdentifier: "seg4", sender: self)
}


override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "seg1" {
        let tabVC = segue.destination as! UITabBarController
        let navVC = tabVC.viewControllers![0] as! UINavigationController
        let destVC = navVC.viewControllers[0] as! Seq1  // ==> this transition is working

        print(destVC)

    }
    else if segue.identifier == "seg4"{
        let tabVC = segue.destination as! UITabBarController
        let navVC = tabVC.viewControllers![3] as! UINavigationController
        let destVC = navVC.viewControllers[0] as! Seq4  // ==> this transition is working
        destVC.hello()
        print(destVC)
    }

}

Seq1 类:UIViewController {

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

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

Seq2 类:UIViewController {

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

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}Seq3 类:UIViewController {

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


}



override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}Seq4 类:UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    print("Hello")
    // Do any additional setup after loading the view, typically from a nib.
}

func hello() {
    print("Hello")
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

注意:标签栏 Controller 将始终显示 FirstVC。因为它是默认选择。如果需要，更改 selectedIndex = 3