SwiftUI detect delete button pressed

Question

I'm using SwiftUI, but I'm coding my own custom text mask, but I need to delete when a user press the "delete" key. I'm using the onChange method, but it is not detecting when special keys are pressed. Currently I'm using:

TextField(self.placeholder, text: self.$text)
.onChange(of: self.text, perform: { value in
    print(value)
})

Is there a way to detect if the delete button is pressed? Or should I use the UITextField instead of TextField ?

You should need to use UITextField. Next should be helpful : stackoverflow.com/a/65840157/14733292 — Raja Kishan
– Raja Kishan, Commented Feb 5, 2021 at 5:08
Answered with a full implementation example here (stackoverflow.com/questions/76684922/…) — Joule87
– Joule87, Commented Nov 19, 2023 at 16:26

ARR · Accepted Answer · 2021-02-05 11:57:11Z

4

Well you could use a hacky way for this.

First we will hold a count of the current characters the text string has.
Whenever the user presses backspace we check in the onChange handler if the previous character count is higher than the new character count
if that is the case we delete the whole string, or whatever you want to do when the delete button is pressed.

import SwiftUI
struct SquareView: View {
    
    var placeholder = "test"
    @State var text = "test"
    @State var textLen = 4
    
    var body: some View {
        VStack {
            TextField(self.placeholder, text: self.$text)
            .onChange(of: self.text, perform: { value in
                if value.count < textLen {
                    self.text = "" // << removed the whole text but here you can insert anything you want to do when the delete button is pressed
                }
                textLen = value.count
            })
        }
    }
}

Keep in mind that this is a hacky way and brings risks. For example if users paste something which is shorter than the current text.

answered Feb 5, 2021 at 11:57

ARR

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1 Comment

Đorđe Nilović Over a year ago

.onChange is not triggered when the user presses backspace.

Rich · Accepted Answer · 2022-06-03 13:10:05Z

2

MVVM + Combine way:

class RecoveryPasswordViewModel: ObservableObject {
  @Published var email: String = ""
  @Published var isValidTextFieldStatus = true
  var cancellables = Set<AnyCancellable>()

  init() {
    setTextFieldToValidWhenUserDelete()
  }

  func setTextFieldToValidWhenUserDelete() {
    $email
        .scan("", { [weak self] previousInput, currentInput in
            if previousInput.count > currentInput.count {
                self?.isValidTextFieldStatus = true
            }
            return currentInput
        })
        .sink { _ in }
        .store(in: &cancellables)
 }
}

answered Jun 3, 2022 at 13:10

Rich

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