[SwiftUI] Wrapping a UITextField into SwiftUI to use different keyboards, e.g: UIKeyboardType.twitter, UIKeyboardType.numbersAndPunctuation

TextFieldTyped.swift

//  Created by Thiago Holanda on 22.06.19.
// twitter.com/tholanda

import SwiftUI

struct ContainerView: View {
    @State var decimal = ""
    @State var twitter = ""
    @State var url     = ""
    @State var search  = ""
    
    var body: some View {
        VStack(spacing: 2) {
            HStack {
                Text("Decimal Pad:")
                    .font(.body)
                    .foregroundColor(.gray)
                
                TextFieldTyped(keyboardType: .decimalPad, text: self.$decimal)
                    .background(Color.gray)
                    .frame(width: 200)

                Text("Text: \(self.decimal)")
                    .font(.body)
                    .foregroundColor(.gray)
                    .frame(width: 200)
            }
            
            HStack {
                Text("Twitter Pad:")
                    .font(.body)
                    .color(.gray)
                
                TextFieldTyped(keyboardType: .twitter, text: self.$twitter)
                    .background(Color.gray)
                    .frame(width: 200)

                Text("Text: \(self.twitter)")
                    .font(.body)
                    .foregroundColor(.gray)
                    .frame(width: 200)
            }
            
            HStack {
                Text("URL Pad:")
                    .font(.body)
                    .foregroundColor(.gray)
                
                TextFieldTyped(keyboardType: .URL, text: self.$url)
                    .background(Color.gray)
                    .frame(width: 200)

                Text("Text: \(self.url)")
                    .font(.body)
                    .foregroundColor(.gray)
                    .frame(width: 200)
            }
            
            HStack {
                Text("WebSearch Pad:")
                    .font(.body)
                    .foregroundColor(.gray)
                
                TextFieldTyped(keyboardType: .webSearch, text: self.$search)
                    .background(Color.gray)
                    .frame(width: 200)

                Text("Text: \(self.search)")
                    .font(.body)
                    .foregroundColor(.gray)
                    .frame(width: 200)
            }
        }
        .frame(height: 40)
    }
}

struct TextFieldTyped: UIViewRepresentable {
    let keyboardType: UIKeyboardType
    @Binding var text: String
    
    func makeUIView(context: Context) -> UITextField {
        let textField = UITextField(frame: .zero)
        textField.keyboardType = self.keyboardType
        textField.delegate = context.coordinator
        
        _ = NotificationCenter.default.publisher(for: UITextField.textDidChangeNotification, object: textField)
            .compactMap {
                guard let field = $0.object as? UITextField else {
                    return nil
                }
                return field.text
            }
            .sink {
                self.text = $0
            }
        
        return textField
    }
    
    func updateUIView(_ uiView: UITextField, context: Context) {
        
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    
    class Coordinator: NSObject, UITextFieldDelegate {
        var parent: TextFieldTyped
        
        init(_ textField: TextFieldTyped) {
            self.parent = textField
        }
        
//        func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
//            if let value = textField.text {
//                parent.text = value
//                parent.onChange?(value)
//            }
//
//            return true
//        }
    }
}


#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        Group {
            ContainerView().previewLayout(.fixed(width: 700, height: 200))
            ContainerView().environment(\.colorScheme, .dark).previewLayout(.fixed(width: 600, height: 400))
        }
        
    }
}
#endif

Is there a reason not to use the default modifiers?

TextField(...)
    .keyboardType(.decimalPad)
    .textContentType(.creditCardNumber)

Is there a reason not to use the default modifiers?

TextField(...)
    .keyboardType(.decimalPad)
    .textContentType(.creditCardNumber)

Not today. I created this gist on June 22, 2019, at the moment, SwiftUI was beta and didn't have the keyboardType property yet.