First Responder Logger for iOS to debug which view and their parent view controller has focus for iOS keyboard issues.

FirstResponderLogger.swift

class FirstResponderLogger {
    
    private static var isRunning : Bool = false
    
    static func log(){
        if (!FirstResponderLogger.isRunning) {
            FirstResponderLogger.isRunning = true
            Task {
                while true {
                    try? await Task.sleep(nanoseconds: 1_000_000_000)
                    await MainActor.run {
                        if let firstResponder = UIResponder.current {
                            let address = String(format: "%p", Int(bitPattern: ObjectIdentifier(firstResponder)))
                            
                            // Walk responder chain to find nearest VC
                            var next: UIResponder? = firstResponder.next
                            var parentVC: UIViewController?
                            while let responder = next {
                                if let vc = responder as? UIViewController {
                                    parentVC = vc
                                    break
                                }
                                next = responder.next
                            }
                            
                            let vcName = parentVC.map { "\(type(of: $0))" } ?? "none"
                            Orchard.v("First Responder: \(vcName) - \(type(of: firstResponder))[\(address)]")
                        }
                    }
                }
            }
        }
    }
}


extension UIView {
    var firstResponder: UIView? {
        guard !isFirstResponder else { return self }
        return subviews.lazy.compactMap { $0.firstResponder }.first
    }
}

extension UIResponder {
    private static weak var _firstResponder: UIResponder?

    static var current: UIResponder? {
        UIResponder._firstResponder = nil
        UIApplication.shared.sendAction(
            #selector(storeFirstResponder),
            to: nil, from: nil, for: nil
        )
        return UIResponder._firstResponder
    }

    @objc private func storeFirstResponder() {
        UIResponder._firstResponder = self
    }
}

FirstResponderLogger.log()