Question

我正在尝试调用根控制器，但我不知道调用它的代码。我使用条件，它将检查以前的视图控制器是什么，并且代码块将根据它是什么运行。这是我的代码：

SecondViewController

override func viewDidLoad ( ) {
     super.viewDidLoad ( )

     let previousController = storyboard!.instantiateViewControllerWithIdentifier ("firstViewController") as? FirstViewController

     //HELP IN LINE BELOW
     //if root view controller == previousController {
              //run some code
     //}
}

Answer 1

let stack = self.navigationController.viewControllers
if (stack.count > 1) {
    let previousController = stack[stack.count-2]
}

或者如果您没有导航控制器

let previousController = self.presentingViewController

另外，为了清楚起见，根视图控制器将是堆栈中的第一个视图控制器，即：

self.navigationController.viewControllers.firstObject

或

var previousController : UIViewController = self
var rootController : UIViewController?
do {
    var rootViewController = previousController
    var previousController = rootViewController.presentingViewController
} while (previousController != nil)

调用Swift中的前一个视图控制器

1 个答案: