How do I detect if keyboard is currently shown, if I transitioned from another view controller that was already showing the keyboard?

Question

I have a view controller that makes a UITextField firstResponder on ViewWillAppear. Normally I could just rely on a UIKeyboardWillShow notification to detect if the keyboard has shown, but this won't trigger if I came into the current view controller while the keyboard was already showing.

Anyone have any ideas?

Answer 1

I noticed while debugging view hierarchy that when keyboard is presented there's UIRemoteKeyboardWindow in hierarchy.

First we can add extension to UIApplication to check window hierarchy for UIRemoteKeyboardWindow:

extension UIApplication {
    var isKeyboardPresented: Bool {
        if let keyboardWindowClass = NSClassFromString("UIRemoteKeyboardWindow"), self.windows.contains(where: { $0.isKind(of: keyboardWindowClass) }) {
            return true
        } else {
            return false
        }
    }
}

Then in viewDidLoad, or where needed we can check:

if UIApplication.shared.isKeyboardPresented {
   print("Keyboard is presented")
}

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Although this method is not fully tested and UIRemoteKeyboardWindow is in private headers that's why NSClassFromString is needed for check. Use it with concern!