找回parentViewController

Question

我有一台PhoneViewController : UIViewController

let phonePage = storyboard.instantiateViewControllerWithIdentifier("phoneViewController") as! PhoneViewController

我从两个不同的控制器来展示它。

// UIViewController1
self.navigationController?.pushViewController(phonePage, animated: true)

// UIViewController2
self.presentViewController(phonePage.embedInNavController(), animated: true, completion: nil)

我希望有一个必须检测哪个控制器是它的父控制器。我怎么能做到这一点呢？

Answer 1

简短的答案是：

if let navController = self.navigationController {
    return navController.viewControllers[navController.viewControllers.count - 1]
    // take care if count <= 1
else {
    return self.parent
}

但这是你真正想要的吗？根据他的父母是谁，你试图实现什么行为？我不知道这个问题的答案，但是你应该让你的代码具有可读性。让我举一个例子来解释：

let phonePage = storyboard.instantiateViewControllerWithIdentifier("phoneViewController") as! PhoneViewController

// Option 1
self.navigationController?.pushViewController(phonePage, animated: true)
phonePage.mode = PhonePageMode.list


// Option 2
self.presentViewController(phonePage.embedInNavController(), animated: true, completion: nil)
phonePage.mode = PhonePageMode.grid

// In your PhoneViewController class
switch self.mode {
    case .list: // present as a list
    case .grid: // present as a grid
}

的可读性比：

let phonePage = storyboard.instantiateViewControllerWithIdentifier("phoneViewController") as! PhoneViewController

// Option 1
self.navigationController?.pushViewController(phonePage, animated: true)

// Option 2
self.presentViewController(phonePage.embedInNavController(), animated: true, completion: nil)

// In your PhoneViewController class
guard let parent = self.parentViewController else { return }
if parent is ThisClassWhichWantsAList {
    // present as list
} else if parent is ThisOtherClassWhichWantsAGrid {
    // present as grid
}

如果你想使用它的父元素作为一个条件来做不同的事情，你更愿意使用一个额外的属性。你未来的自我将会心存感激。

Answer 2

你可以试试这段代码：

if let wd = self.window {
       var vc = wd.rootViewController
       if(vc is UINavigationController){
            vc = (vc as UINavigationController).visibleViewController
        }

        if(vc is YourViewController){
            //your code
        }
    }

Answer 3

如果你的视图控制器是从navigationViewController推送的，那么parentViewController中的父类是可用的，如果呈现了，那么presentationController中的父类是可用的。

您可以通过以下方式签到：

if let parentVC = self.navigationController.parentViewController{
   //parentVC.className

}

if let presentedVC = self.navigationController?.presentationController{
   //presentedVC.className      
}