swift - 如何檢查如果一個特定的viewController是以前的viewController

Question

我想檢測如果我以前的viewController是一個特定的，如果它是當我按回它將加載tabBar控制器。 我改變與revealViewController 視圖控制器這裏是我的代碼： 在這裏，我保存以前的視圖控制器：

let newVC = 
self.storyboard?.instantiateViewController(withIdentifier: 
storyboardIdentifiers.newViewControllerID) as! newViewController   
newVC.previousVC = self 
self.revealViewController().setFront(newVC, animated: true) 

這是我回來的行動，我需要檢查，如果以前是第一的viewController

func backAction() { 
let first = self.storyboard?.instantiateViewController(withIdentifier: storyboardIdentifiers.firstViewControllerID) as! firstViewController 
let second = self.storyboard?.instantiateViewController(withIdentifier: storyboardIdentifiers.secondViewControllerID) as! secondViewController 

if previousVC == first || previousVC == second { 
      previousVC = self.storyboard?.instantiateViewController(withIdentifier: storyboardIdentifiers.revealViewControllerID) as! SWRevealViewController 
self.revealViewController().setFront(previousVC, animated: true) 
} 
else { 
self.revealViewController().setFront(previousVC, animated: true) 
} 

但是當我按回它並沒有檢測到它來自這些視圖控制器之一。

當我打印的「自我」它給了我這樣的結果

<MyPackege.firstViewController: 0x7f9e80f2b5a0> 

但它不會加載TabBarController

Answer 1

而不是使用==運營商嘗試使用isKind(of:)方法來檢查的視圖 - 控制

類型

func backAction() { 
let first = self.storyboard?.instantiateViewController(withIdentifier: storyboardIdentifiers.firstViewControllerID) as! firstViewController 
let second = self.storyboard?.instantiateViewController(withIdentifier: storyboardIdentifiers.secondViewControllerID) as! secondViewController 

if previousVC.isKind(of:firstViewController) || previousVC.isKind(of:secondViewController) { 
      previousVC = self.storyboard?.instantiateViewController(withIdentifier: storyboardIdentifiers.revealViewControllerID) as! SWRevealViewController 
self.revealViewController().setFront(previousVC, animated: true) 
} 
else { 
self.revealViewController().setFront(previousVC, animated: true) 
}