> Detect and Block Screenshots in SwiftUI

import SwiftUI
import UIKit

struct ScreenshotDetector: ViewModifier {
    let onScreenshot: () -> Void

    func body(content: Content) -> some View {
        content.onReceive(NotificationCenter.default.publisher(
            for: UIApplication.userDidTakeScreenshotNotification
        )) { _ in
            onScreenshot()
        }
    }
}

extension View {
    func onScreenshot(perform action: @escaping () -> Void) -> some View {
        modifier(ScreenshotDetector(onScreenshot: action))
    }
}

struct AccountView: View {
    @State private var showWarning = false

    var body: some View {
        Text("Account Number: 1234-5678-9012")
            .onScreenshot { showWarning = true }
            .alert("Screenshot Detected", isPresented: $showWarning) {
                Button("OK", role: .cancel) { }
            } message: {
                Text("Please keep this information private.")
            }
    }
}

import SwiftUI
import UIKit

struct SecureContent<Content: View>: UIViewRepresentable {
    @ViewBuilder var content: Content

    func makeCoordinator() -> Coordinator { Coordinator() }

    func makeUIView(context: Context) -> UITextField {
        let field = UITextField()
        field.isSecureTextEntry = true
        field.isUserInteractionEnabled = false

        // iOS applies secure rendering to this internal view. It's undocumented,
        // so if it ever goes away, show nothing rather than exposing the content.
        guard let canvas = field.subviews.first else { return field }

        let host = UIHostingController(rootView: content)
        host.view.backgroundColor = .clear
        host.view.translatesAutoresizingMaskIntoConstraints = false
        canvas.addSubview(host.view)

        NSLayoutConstraint.activate([
            host.view.leadingAnchor.constraint(equalTo: field.leadingAnchor),
            host.view.trailingAnchor.constraint(equalTo: field.trailingAnchor),
            host.view.topAnchor.constraint(equalTo: field.topAnchor),
            host.view.bottomAnchor.constraint(equalTo: field.bottomAnchor),
        ])

        context.coordinator.host = host
        return field
    }

    func updateUIView(_ field: UITextField, context: Context) {
        context.coordinator.host?.rootView = content
    }

    final class Coordinator {
        var host: UIHostingController<Content>?
    }
}

struct BalanceView: View {
    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Account Summary").font(.title)

            SecureContent {
                Text("$10,234.56").font(.largeTitle.bold())
            }
            .frame(height: 50)
        }
        .padding()
    }
}