There are a number of interesting responses here and great ideas.
Encountering a situation where I needed to enforce input using a SwiftUI TextField the same way I had done with the textField(_:shouldChangeCharactersIn:replacementString:) delegate method, I found simple filtering works nicely.
@State var textInput: String = ""
...
TextField("numerical entries only", text: $textInput)
.onChange(of: textInput) { newValue in
let numberCharacterSet = "0123456789"
textInput = newValue.filter { numberCharacterSet.contains($0) }
}
syvertsj
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Post
Replies
Boosts
Views
Activity
Checking for delete entry.
With the UIKit shouldChangeCharactersIn... delegate method the backspace is the equivalent of an empty string.
In the SwiftUI TextField .onChange() block it is necessary to use a capture list for the @State property being updated and do a comparison between that and the new value in the closure.
@State var textInput: String = ""
var body: some View {
TextField("numerical entries only", text: $textInput)
.onChange(of: textInput) { [textInput] newValue in
if newValue.count < textInput.count { print("- backspace detected") }
}
...