Ios Swift-appDelegate中的pushViewController，rootViewController.navigationController为零

在遵循一些指南时遇到问题，特别是

我正在设置url方案，从另一个应用程序启动该应用程序效果很好，但传入主机或url似乎并没有起到应有的作用。我在所有视图布局中使用故事板和界面生成器

本指南在appDelegate中显示此openURL：

-(BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation{
    if([[url host] isEqualToString:@"page"]){
        if([[url path] isEqualToString:@"/page1"]){
            [self.mainController pushViewController:[[Page1ViewController alloc] init] animated:YES];
        }
    return YES;
    }
}

if let rootViewController = self.window!.rootViewController as? UINavigationController {
   let storyboard = UIStoryboard(name: "Main", bundle: nil)

   if let viewcontroller = storyboard.instantiateViewController(withIdentifier: "DiscussionBoardSID") as? DiscussionBoardViewController {
      viewcontroller.postID = "13" ///pass data to your viewcontroller
      rootViewController.pushViewController(viewcontroller, animated: true)
   }
}

这是我的简化版本，用swift从一些其他来源获得，即 我现在跳过url主机的条件，以删除问题中潜在的其他变量

func application(application: UIApplication, openURL url: NSURL, sourceApplication: String, annotation: AnyObject?) -> Bool {
    var rootViewController = self.window!.rootViewController
    let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
    var profileViewController = mainStoryboard.instantiateViewControllerWithIdentifier("profile") as ProfileViewController

    rootViewController.navigationController.popToViewController(profileViewController, animated: true)

    return true

}

swift版本会导致崩溃：

致命错误：在展开可选值时意外发现nil

---

rootViewController似乎还没有navigationController？

在我的例子中，rootViewController实际上是UINavigationController类型，因此在声明上强制转换它允许我直接在其上调用pushToViewController

func application(application: UIApplication, openURL url: NSURL, sourceApplication: String, annotation: AnyObject?) -> Bool {
    let rootViewController = self.window!.rootViewController as! UINavigationController
    let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
    let profileViewController = mainStoryboard.instantiateViewController(withIdentifier: "InstructionVC") as! InstructionVC
    rootViewController.pushViewController(profileViewController, animated: true)
    return true

}

SWIFT 4:使用条件绑定和链接的安全推送方式

在一行代码中：

Swift 3:

self.navigationController!.pushViewController(self.storyboar‌​d!.instantiateViewCo‌​ntroller(withIdentif‌​ier: "view2") as UIViewController, animated: true)

---

APPDELEGATE到页面：

        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let loginPageView = mainStoryboard.instantiateViewControllerWithIdentifier("leadBidderPagerID") as! LeadBidderPage
        var rootViewController = self.window!.rootViewController as! UINavigationController
        rootViewController.pushViewController(loginPageView, animated: true)

        let loginPageView = self.storyboard?.instantiateViewControllerWithIdentifier("scoutPageID") as! ScoutPage
        self.navigationController?.pushViewController(loginPageView, animated: true)

逐页：

        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let loginPageView = mainStoryboard.instantiateViewControllerWithIdentifier("leadBidderPagerID") as! LeadBidderPage
        var rootViewController = self.window!.rootViewController as! UINavigationController
        rootViewController.pushViewController(loginPageView, animated: true)

        let loginPageView = self.storyboard?.instantiateViewControllerWithIdentifier("scoutPageID") as! ScoutPage
        self.navigationController?.pushViewController(loginPageView, animated: true)

更新为swift 3/4。 投票最多的“一行代码”不起作用，因为“self”中没有导航控制器

---

Swift 3&4从AppDelegate推送viewcontroller的最佳实践：

-(BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation{
    if([[url host] isEqualToString:@"page"]){
        if([[url path] isEqualToString:@"/page1"]){
            [self.mainController pushViewController:[[Page1ViewController alloc] init] animated:YES];
        }
    return YES;
    }
}

if let rootViewController = self.window!.rootViewController as? UINavigationController {
   let storyboard = UIStoryboard(name: "Main", bundle: nil)

   if let viewcontroller = storyboard.instantiateViewController(withIdentifier: "DiscussionBoardSID") as? DiscussionBoardViewController {
      viewcontroller.postID = "13" ///pass data to your viewcontroller
      rootViewController.pushViewController(viewcontroller, animated: true)
   }
}

---

如果要使用NavigationBar显示和关闭或关闭（动画：true，完成：nil） 使用选项设置addObserver indidFinishLaunchingWithOptions

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {



NotificationCenter.default.addObserver(self, selector: #selector(devolucionNoPresencial), name: NSNotification.Name(rawValue: "DevolucionNoPresencial"), object: nil)
        return true
}

那么你的方法呢

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
//do your code for .active, .inactive .background, etc

 if let userInfo = response.notification.request.content.userInfo as? [String : AnyObject] {
            if UIApplication.shared.applicationState == .active {
//activate the notificationCenter so you can call your @objc method
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "DevolucionNoPresencial"), object: nil)
}

添加@objc方法

@objc private func devolucionNoPresencial() {


       //change DevolucionVC for VC you want to present

        if let controller = DevolucionVC() as? DevolucionVC {
            if let window = self.window, let rootViewController = window.rootViewController {
                var currentController = rootViewController
                while let presentedController = currentController.presentedViewController {
                    currentController = presentedController
                }
                currentController.present(controller, animated: true, completion: nil)
            }
        }

    }

}

---

Swift 2.0

self.navigationController！。pushViewController（self.storyboard？.instanceeviewcontrollerwhiteIdentifier（“view2”）为！UIViewController，动画：true）

Swift 3.0 self.navigationController！。pushViewController（self.storyboard！。实例化eViewController（标识符为：“view2”）作为UIViewController，动画：true）self.navigationController为零。如何推送？@Umitk PushViewController是导航API的一部分。因此，如果没有“UINavigationController”，您可以继续按任何键。更新了处理推送的最安全方法的答案我知道这已经进行了一年，但我想知道，如果推送到实例化的新视图控制器，这是否算作一个可以准备的步骤？谢谢。在遵循一些指南，只是从故事板抓取导航控制器，它只是不起作用，这就是诀窍！这是我在几个小时内看到的唯一有用的帖子。谢谢我一直在找一页一页地找。我在你们家找不到窗户solutin@RishabhDugar您是否在AppDelegate类中？不，我在控制器文件中解决方案是从AppDelegate获取导航控制器，而不是查看控制器。在您的情况下，上面的“一行代码”解决方案可能适合您