swift - 我如何检查特定的 viewController 是否是以前的 viewController

Question

我正在尝试检测我以前的 viewController 是否是一个特定的，如果是当我按下它时它将加载 tabBar 控制器。 我正在使用revealViewController 更改视图控制器 这是我的代码： 这里我保存了之前的视图控制器：

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

这是我的后退动作，我需要检查上一个是否是第一个 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)
}

但是当我按下它时，它没有检测到它来自这些视图控制器之一。

当我打印“self”时，它给了我这个结果

<MyPackege.firstViewController: 0x7f9e80f2b5a0>

但它不会加载 TabBarController

Answer 1

不要使用==操作符尝试使用isKind(of: )方法来检查viewcontroller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)
}