Swiftui CustomTextField

CustomTextField.swift

// customized text field based on @Anshuman Singh https://stackoverflow.com/questions/58311022/autofocus-textfield-programmatically-in-swiftui

import SwiftUI

struct CustomTextField: UIViewRepresentable {
    class Coordinator: NSObject, UITextFieldDelegate {
        @Binding var textInput: String
        @Binding var nextResponder: Bool?
        @Binding var isResponder: Bool?
        var maxLength: Int?
        var onSubmit: (() -> Void)?

        init(
            text: Binding<String>,
            nextResponder: Binding<Bool?>,
            isResponder: Binding<Bool?>,
            maxLength: Int?,
            onSubmit: (() -> Void)?
        ) {
            _textInput = text
            _isResponder = isResponder
            _nextResponder = nextResponder
            self.maxLength = maxLength
            self.onSubmit = onSubmit
        }

        func textField(
            _ textField: UITextField,
            shouldChangeCharactersIn range: NSRange,
            replacementString string: String
        ) -> Bool {
            guard let maxLength = maxLength else {
                return true
            }

            guard let textFieldText = textField.text,
                let rangeOfTextToReplace = Range(range, in: textFieldText) else {
                return false
            }
            let substringToReplace = textFieldText[rangeOfTextToReplace]
            let count = textFieldText.count - substringToReplace.count + string.count
            return count <= maxLength
        }

        func textFieldDidChangeSelection(_ textField: UITextField) {
            if textField.markedTextRange == nil {
                textInput = textField.text ?? ""
            }
        }

        func textFieldDidBeginEditing(_: UITextField) {
            DispatchQueue.main.async {
                self.isResponder = true
            }
        }

        func textFieldShouldReturn(_: UITextField) -> Bool {
            if let onSubmit = onSubmit {
                onSubmit()
            }

            DispatchQueue.main.async {
                self.isResponder = false
                if self.nextResponder != nil {
                    self.nextResponder = true
                }
            }

            return true
        }
    }

    @Binding var text: String
    @Binding var nextResponder: Bool?
    @Binding var isResponder: Bool?

    var isSecured: Bool = false
    var keyboard: UIKeyboardType
    var returnKeyType: UIReturnKeyType?

    var maxLength: Int?
    var textColor: UIColor = .white
    var placeholder: String?
    var placeholderColor: UIColor = .white
    var onSubmit: (() -> Void)?

    func makeUIView(context: UIViewRepresentableContext<CustomTextField>) -> UITextField {
        let textField = UITextField(frame: .zero)
        textField.isSecureTextEntry = isSecured
        textField.autocapitalizationType = .none
        textField.autocorrectionType = .no
        textField.keyboardType = keyboard
        textField.returnKeyType = returnKeyType ?? UIReturnKeyType.default
        textField.textColor = textColor
        textField.delegate = context.coordinator

        if placeholder != nil {
            textField.attributedPlaceholder = NSAttributedString(
                string: placeholder!,
                attributes: [NSAttributedString.Key.foregroundColor: placeholderColor]
            )
        }

        return textField
    }

    func makeCoordinator() -> CustomTextField.Coordinator {
        Coordinator(
            text: $text,
            nextResponder: $nextResponder,
            isResponder: $isResponder,
            maxLength: maxLength,
            onSubmit: onSubmit
        )
    }

    func updateUIView(_ uiView: UITextField, context _: UIViewRepresentableContext<CustomTextField>) {
        uiView.text = text
        if isResponder ?? false {
            uiView.becomeFirstResponder()
        }
    }
}