ios - 访问 UInavigationcontroller 嵌入式 View Controller ？

Question

我有一个 iPhone 应用程序(带有 Storyboard)，我在其中使用 View Controller 作为初始 View Controller 。然后我添加了一个 View Controller 场景并向其中嵌入了一个导航 Controller 。我希望该导航 Controller 能够成为窗口的 Root View Controller 。当我尝试以编程方式访问该 View Controller 并将另一个 View Controller 推送到它时，导航 Controller 不存在，我还收到嵌入到该 View Controller 的导航 Controller 上无法访问场景的警告。我是试图像这样实现它

` 
    UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Main"
                                                             bundle: nil];

    UINavigationController *controller =(UINavigationController *)[mainStoryboard instantiateViewControllerWithIdentifier:@"Newcontroller"];
    NSLog(@"%@",[controller topViewController]);

    [appdelegate.window setRootViewController:controller];
`  

谁能帮我如何以编程方式访问这个导航 Controller ？

Answer 1

你需要这样做

第一步

Create the custom class of NavigationController , for example NavigationViewController (SubClass of UINavigationController).

第二步

Assign the class name for that NavigationController in Identity Inspector.

第三步

Set the Storyboard ID for that class in Identity Inspector Xcode.

第四步

Finally access the class via Code, for example

UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Main"
                                                         bundle: nil];

NavigationViewController *controller =(NavigationViewController *)[mainStoryboard instantiateViewControllerWithIdentifier:@"navigate"];
NSLog(@"%@",[controller topViewController]);

[appdelegate.window setRootViewController:controller];

例如