swift-如何檢查特定的viewController是否為先前的viewController

Question

我正在嘗試檢測我以前的viewController是否是特定的，如果是當我按回時它將加載tabBar控制器。 我正在使用revealViewController更改視圖控制器，這是我的代碼：在這里，我保存了以前的視圖控制器：

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

這是我的后動作，我需要檢查以前是否是第一個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)
}

但是當我按回它時，它不會檢測到它來自這些視圖控制器之一。

當我打印“自我”時，它給我這個結果

<MyPackege.firstViewController: 0x7f9e80f2b5a0>

但它不會加載TabBarController

Answer 1

而不是使用==運算符，請嘗試使用isKind(of: )方法來檢查viewcontroller的類型。

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)
}