How to set textfield character limit SwiftUI? - ios

Question

I'm using SwiftUi version 2 for my application development. I'm facing issue with textfield available in SwiftUI. I don't want to use UITextField anymore. I want to limit the number of Characters in TextField. I searched a lot and i find some answer related to this but those answer doesn't work for SwiftUI version 2.
class textBindingManager: ObservableObject{
let characterLimit: Int
#Published var phoneNumber = "" {
didSet {
if phoneNumber.count > characterLimit && oldValue.count <= characterLimit {
phoneNumber = oldValue
}
}
}
init(limit: Int = 10) {
characterLimit = limit
}
}
struct ContentView: View {
#ObservedObject var textBindingManager = TextBindingManager(limit: 5)
var body: some View {
TextField("Placeholder", text: $textBindingManager.phoneNumber)
}
}

Answer 1

No need to use didSet on your published property. You can add a modifier to TextField and limit the string value to its prefix limited to the character limit:
import SwiftUI
struct ContentView: View {
#ObservedObject var textBindingManager = TextBindingManager(limit: 5)
var body: some View {
TextField("Placeholder", text: $textBindingManager.phoneNumber)
.padding()
.onChange(of: textBindingManager.phoneNumber, perform: editingChanged)
}
func editingChanged(_ value: String) {
textBindingManager.phoneNumber = String(value.prefix(textBindingManager.characterLimit))
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
class TextBindingManager: ObservableObject {
let characterLimit: Int
#Published var phoneNumber = ""
init(limit: Int = 10){
characterLimit = limit
}
}

Answer 2

The following should be the simpliest. It limits the number of characters to 10.
struct ContentView: View {
#State var searchKey: String = ""
var body: some View {
TextField("Enter text", text: $searchKey)
.onChange(of: searchKey) { newValue in
if newValue.count > 10 {
self.searchKey = String(newValue.prefix(10))
}
}
}
}

Answer 3

This solution wraps everything up in a new Component. You could adapt this to perform other parsing / pattern checking quite easily.
struct ContentView : View {
#State private var myTextValue: String = ""
var body: some View {
LimitedTextField(value: $myTextValue, charLimit: 2)
}
}
struct LimitedTextField : View {
#State private var enteredString: String = ""
#Binding var underlyingString: String
let charLimit : Int
init(value: Binding<String>, charLimit: Int) {
_underlyingString = value
self.charLimit = charLimit
}
var body: some View {
HStack {
TextField("", text: $enteredString, onCommit: updateUnderlyingValue)
.onAppear(perform: { updateEnteredString(newUnderlyingString: underlyingString) })
.onChange(of: enteredString, perform: updateUndelyingString)
.onChange(of: underlyingString, perform: updateEnteredString)
}
}
func updateEnteredString(newUnderlyingString: String) {
enteredString = String(newUnderlyingString.prefix(charLimit))
}
func updateUndelyingString(newEnteredString: String) {
if newEnteredString.count > charLimit {
self.enteredString = String(newEnteredString.prefix(charLimit))
underlyingString = self.enteredString
}
}
func updateUnderlyingValue() {
underlyingString = enteredString
}
}