pretend screenshot in flutter

pretend_screenshot.swift

import UIKit
import Flutter

@main
@objc class AppDelegate: FlutterAppDelegate {
    
    var eventSink: FlutterEventSink?
    var field = UITextField()
    
    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        
        GeneratedPluginRegistrant.register(with: self)
        let result = super.application(application, didFinishLaunchingWithOptions: launchOptions)
        
        let controller = window.rootViewController as! FlutterViewController
        let eventChannel = FlutterEventChannel(name: "screen_capture_event", binaryMessenger: controller.binaryMessenger)
        eventChannel.setStreamHandler(self)

        NotificationCenter.default.addObserver(
            self,
            selector: #selector(handleScreenCaptureChange),
            name: UIScreen.capturedDidChangeNotification,
            object: nil
        )
        
        addSecuredView()

        return result
        //return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
    
    override func applicationWillResignActive(_ application: UIApplication) {
        field.isSecureTextEntry = false
    }
    override func applicationDidBecomeActive(_ application: UIApplication) {
        field.isSecureTextEntry = true
    }
    
    private func addSecuredView() {
        if (!window.subviews.contains(field)) {
            window.addSubview(field)
            field.centerYAnchor.constraint(equalTo: window.centerYAnchor).isActive = true
            field.centerXAnchor.constraint(equalTo: window.centerXAnchor).isActive = true
            window.layer.superlayer?.addSublayer(field.layer)
            if #available(iOS 17.0, *) {
                field.layer.sublayers?.last?.addSublayer(window.layer)
            } else {
                field.layer.sublayers?.first?.addSublayer(window.layer)
            }
        }
    }
    
    @objc func handleScreenCaptureChange() {
        let isCaptured = UIScreen.main.isCaptured
        eventSink?(isCaptured)
    }
    
    @objc func userDidTakeScreenshot() {
        print("📸 Screenshot detected!")
        eventSink?(true)
    }
}

extension UIWindow {
    func makeSecure() {
        let secureField = UITextField()
        secureField.isSecureTextEntry = true
        secureField.isHidden = true
        self.addSubview(secureField)
        secureField.translatesAutoresizingMaskIntoConstraints = false
        secureField.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
        secureField.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true

        // Important: Add its layer to your window
        self.layer.superlayer?.addSublayer(secureField.layer)
    }
}

extension AppDelegate: FlutterStreamHandler {
    func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
        self.eventSink = events
        events(UIScreen.main.isCaptured)
        return nil
    }

    func onCancel(withArguments arguments: Any?) -> FlutterError? {
        self.eventSink = nil
        return nil
    }
    
    func sendDataToFlutter(data: Any) {
        eventSink?(data)
    }
}

class ScreenCaptureHandler: NSObject, FlutterStreamHandler {
    var isCaptured: Bool

    init(isCaptured: Bool) {
        self.isCaptured = isCaptured
    }

    func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
        events(isCaptured)
        return nil
    }

    func onCancel(withArguments arguments: Any?) -> FlutterError? {
        return nil
    }
}

//class CustomViewController: UIViewController {
//    private var sdkViewController: UIViewController?
//
//    override func viewDidLoad() {
//        super.viewDidLoad()
//        view.backgroundColor = .white
//        
//        if let sdkVC = sdkViewController {
//            addChild(sdkVC)
//            view.addSubview(sdkVC.view)
//            sdkVC.view.frame = view.bounds
//            sdkVC.didMove(toParent: self)
//        }
//        
//        let backButton = UIBarButtonItem(image: UIImage(systemName: "chevron.backward"), style: .plain, target: self, action: #selector(dismissViewController))
//        backButton.tintColor = UIColor(hex: "#a30041")
//        self.navigationItem.leftBarButtonItem = backButton
//        self.navigationItem.title = "Чат"
//    }
//
//    @objc func dismissViewController() {
//        self.dismiss(animated: true, completion: nil)
//    }
//
//    func setSDKViewController(_ viewController: UIViewController) {
//        self.sdkViewController = viewController
//    }
//}
//
//extension UIColor {
//    convenience init?(hex: String) {
//        var hexCleaned = hex.trimmingCharacters(in: .whitespacesAndNewlines).replacingOccurrences(of: "#", with: "")
//        var rgb: UInt64 = 0
//        Scanner(string: hexCleaned).scanHexInt64(&rgb)
//        self.init(
//            red: CGFloat((rgb & 0xFF0000) >> 16) / 255.0,
//            green: CGFloat((rgb & 0x00FF00) >> 8) / 255.0,
//            blue: CGFloat(rgb & 0x0000FF) / 255.0,
//            alpha: 1.0
//        )
//    }
//}