What is in SwiftUI for UITextFieldDelegate and keyBoardType?

Question

Created Sep ’20

Replies 2

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Participants 2

Hi

I have a simple UIKit app that lets the user enter temperatures in floating point and converts them to a different unit. So steer the user in the right direction, first I made the UITextField.keyboardType property = decimalPad.

Then I set the UITextField.delegate to a UITextFieldDelegate with the method textfield(:shouldChangeCharactersIn:replacementString)

I want to convert the app to SwiftUI but I haven't found any equivalents for those .

Are there replacements for those?

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Answer 1

BabyJ OP

Sep ’20

You can use the following code as a starter.

Code Block Swiftstruct ContentView: View {
	@State private var text = ""
	var body: some View {
		TextField("Enter temperature", text: $text)
			.keyboardType(.decimalPad)
			.onChange(of: text) { newText in
				text = newText.filter { "0123456789.".contains($0) }
			}
	}
}

You may have to add some code to filter out any extra decimal points.

This example formats the number but not while the user is typing.

Code Block Swiftstruct ContentView: View {
	@State private var number: Float?
	var text: Binding<String> {
		Binding<String>(
			get: {
				number == nil ? "" : String(format: "%g", Float(number!))
			},
			set: {
				if $0.isEmpty {
					number = nil
				} else {
					if let value = NumberFormatter().number(from: $0) {
						number = value.floatValue
					}
				}
			}
		)
	}
	var body: some View {
		TextField("Enter temperature", text: text)
			.keyboardType(.decimalPad)
	}
}

1

Answer 2

logistes OP

Sep ’20

Thanks

Code Block .keyboardType(.decimalPad)

is exactly what I wanted.

But there doesn't seem to be a way to intercept keystrokes the way I am using

Code Block textField(_:shouldChangeCharactersIn:replacementString:)

I think that provides a better user experience.

0