How to observe updates in binded values SwiftUI

Question

I'm not sure if I created my custom TextField properly, because I am unable to observe the value changes to an @Binded text. Running the following code, you may observe that print(text) is not executed when you manually enter text into the text field.



import SwiftUI

@main
struct TestOutWeirdTextFieldApp: App {

    @State var text: String = "" {
        didSet {
            print(text)
        }
    }

    var body: some Scene {
        WindowGroup {
            StandardTextField(placeholderText: "Enter text", defaultText: $text)
        }
    }
}


struct StandardTextField: View {

    @State var placeholderText: String {
        didSet {
            print(#line)
            print(placeholderText)
        }
    }
    @Binding var defaultText: String {
        didSet {
            print(#line)
            print(defaultText)
        }
    }
    @State var systemImage: String?
    @State var underlineColor: Color = .accentColor
    @State var edges: Edge.Set = .all
    @State var length: CGFloat? = nil
    @State var secure: Bool = false

    var body: some View {
        HStack {
            if secure {
                SecureField(placeholderText, text: $defaultText)
                    .foregroundColor(underlineColor)
            } else {
                TextField(placeholderText, text: $defaultText)
                    .foregroundColor(underlineColor)
            }
            if let systemImage = systemImage {
                Image(systemName: systemImage)
                    .foregroundColor(.white)
            }
        }
        .overlay(
            Rectangle()
                .frame(height: 2)
                .padding(.top, 35)
        )
        .foregroundColor(underlineColor)
        .padding(edges, length)
    }
}

struct StandardTextView_Previews: PreviewProvider {


    static var previews: some View {
        StandardTextField(placeholderText: "Placement text", defaultText: .constant("")).previewLayout(.sizeThatFits)
    }
}

Asperi · Accepted Answer · 2021-05-03 05:51:14Z

3

Instead of didSet you need to use .onChange(of: modifier, like

    HStack {
       // ... your code here
    }
    .onChange(of: defaultText) { print($0) }      // << this !!
    .overlay(

answered May 3, 2021 at 5:51

Asperi

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