ios - swift - 我如何检查特定的 viewController 是否是前一个 viewController

Question

我正在尝试检测我以前的 viewController 是否是一个特定的，如果是，当我按回它时它将加载 tabBar Controller 。我正在使用 revealViewController 更改 View Controller 这是我的代码:在这里我保存了之前的 View Controller :

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

这是我的后退操作，我需要检查 previous 是否是第一个 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)
}

但是当我按回键时，它没有检测到它来自这些 View Controller 之一。

当我打印“self”时，它给了我这个结果

<MyPackege.firstViewController: 0x7f9e80f2b5a0>

但它不加载 TabBarController

Answer 1

不要使用 == 运算符，而是尝试使用 isKind(of: ) 方法来检查 View Controller 的类型

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)
}