导航控制器未加载（push，存在）另一个viewController

Question

[我无法在单击按钮时加载viewController，因为知道已定义的Vc拥有我要显示的VC的值。

//AppDelegate
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.

    let mainViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(identifier: "ViewController") as! ViewController
    let navVC = UINavigationController.init(rootViewController: mainViewController)
    self.window?.rootViewController = navVC
    self.window?.makeKeyAndVisible()
    return true
}

 //ViewController Class
 class ViewController: UIViewController, UIScrollViewDelegate {

@IBOutlet weak var collectionView: UICollectionView!
@IBOutlet weak var button: UIButton!
@IBOutlet weak var pageController: UIPageControl!

private let reuseIdentifier = /*"CollectionViewCell"*/ "Cell"
let collectionViewImages : [UIImage] = [#imageLiteral(resourceName: "cooov"), #imageLiteral(resourceName: "shutterstock535739452"), #imageLiteral(resourceName: "portraitYoungManLyingBedCheckingHisFeverThermometer232147948490")]
let collectionViewTexts : [String] = [
    "Stay at home ! your health is our Priority",
    "Access Latest Coronavirus articles !",
    "Check up on your health on a daily basis !"
]

override func viewDidLoad() {
    super.viewDidLoad()
    renderButton()
    renderCell()
    pageController.numberOfPages = collectionViewImages.count
    pageController.currentPage = 0
}

@IBAction func buttonClicked(_ sender: UIButton) {
    let signupVC = UIStoryboard.init(name:"SignUp", bundle: nil).instantiateViewController(withIdentifier: "SignUp")
    as! SignUp
self.navigationController?.pushViewController(signupVC, animated: true)
}
 }


//SignUp class The VC that should appear on ButtonClick 
class SignUp : BaseViewController {
override func viewDidLoad() {
    super.viewDidLoad()
 }
}

 //the class that is inherited by ViewController
 class BaseViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    self.navigationController?.navigationBar.isHidden = true
 }
 }
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这里是所提供图片的链接，请检查。https://drive.google.com/drive/folders/1CxysH911PIa3-S9Dx6EUV7DE8vlnEd4l?usp=sharing

Answer 1

这里是可以像这样更改功能并让我知道结果的功能

首先运行一个

@IBAction func buttonClicked(_ sender: UIButton) {
        let signupVC = UIStoryboard.init(name:"SignUp", bundle: nil).instantiateViewController(withIdentifier: "SignUp")

        let navVC = UINavigationController.init(rootViewController: signupVC)
      //  self.present(navVC, animated: true, completion: nil)

        if let nav =  self.navigationController {
            nav.pushViewController(navVC, animated: true)
        } else {
            print("navigation controller not found")
        }
    }

然后尝试展示...，让我知道发生了什么

@IBAction func buttonClicked(_ sender: UIButton) {
        let signupVC = UIStoryboard.init(name:"SignUp", bundle: nil).instantiateViewController(withIdentifier: "SignUp")

        let navVC = UINavigationController.init(rootViewController: signupVC)
        self.present(navVC, animated: true, completion: nil)


    }

Answer 2

您不需要新的UINavigation控制器即可推送。

@IBAction func buttonClicked(_ sender: UIButton) {
    let signupVC = UIStoryboard.init(name:"SignUp", bundle: nil).instantiateViewController(withIdentifier: "SignUp")
        as! SignUp
    self.navigationController?.pushViewController(signupVC, animated: true)
}

此外，如果您使用的是iOS 13.0+和Xcode 11+，SceneDelegate将代替AppDelegate被调用。因此，也尝试将粘贴复制到SceneDelegate。