Check to specific VC in AppDelegate - ios

Question

I'm trying to check specific VC if app is running in foreground. My root view controller class is SWRevealViewController. After that I have a TabBarController and under it there is NavigationController and ViewController under it.
My heirachy is,
SWRevealViewController --> TabBar Controller --> Navigation Controller --> MessageVC --> ChatVC
I want to check in app delegate if app is on ChatVC or not if running on foreground.I have tried this code,
let tabBar:UITabBarController = self.window?.rootViewController as! UITabBarController
let navInTab:UINavigationController = tabBar.viewControllers?[1] as! UINavigationController
let storyboard = UIStoryboard(name: "Dashboard", bundle: nil)
let destinationViewController = storyboard.instantiateViewController(withIdentifier: "ChatDetailViewController") as? ChatDetailViewController
if destinationViewController?.restorationIdentifier == "ChatDetailViewController"
{
print("Yes")
}
else
{
print("No")
}
But app crashes with this error,
Could not cast value of type 'SWRevealViewController' (0x100dc4b20) to 'UITabBarController' (0x211b289f0).
How i can check if app is on ChatVC or not?
Screenshot of storyboard :

Answer 1

I have an extension for it
extension UIApplication {
class func topViewController(base: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
if let nav = base as? UINavigationController {
return topViewController(base: nav.visibleViewController)
}
if let tab = base as? UITabBarController {
let moreNavigationController = tab.moreNavigationController
if let top = moreNavigationController.topViewController, top.view.window != nil {
return topViewController(base: top)
} else if let selected = tab.selectedViewController {
return topViewController(base: selected)
}
}
if let presented = base?.presentedViewController {
return topViewController(base: presented)
}
return base
}
}
USAGE:
if UIApplication.topViewController is YourViewController {
// do smth
}

Answer 2

I never used SWRevealViewController but you can try this.
As you said in your first line "SWRevealViewController is the RooVC" and you are converting the SWRevealViewController to UITabBarController (check below line of your code). This is your crash reason.
let tabBar:UITabBarController = self.window?.rootViewController as! UITabBarController
Now you need to change, UITabBarController to SWRevealViewController
let rootVC = self.window?.rootViewController as! SWRevealViewController
Now get all ViewControllers
if let navController = rootVC.navigationController { // for safety check
for controller in navController.viewControllers {
if controller is ChatVC {
print("Chat VC is available")
break
}
}
}
For safe coding and keeping swift optional binding in mind, you can do code like below,
Updated answer
var haveChatVC = false
if let rootVC = self.window?.rootViewController as? SWRevealViewController,
let tabbar = rootVC.frontViewController as? UITabBarController {
if let requiredNC = tabbar.viewControllers?[1] as? UINavigationController {
for vc in requiredNC.viewControllers {
if vc is ChatVC {
// ...
haveChatVC = true
break
}
}
}
else {
print("Navigation controller not found.")
}
}
else {
print("Unable to get root controller or navigation controller")
}
if haveChatVC {
// do task here when chat vc available
}
else {
// do task here when chat vc not available
}
Note: This is only pseudo code.