Untitled

import Foundation
import UIKit
import Flutter
class ScreenRecordHandler: NSObject {
    private var appDelegate = (UIApplication.shared.delegate as? AppDelegate)
    weak private var screen : UIView? = nil
    static var shared = ScreenRecordHandler()
    func configure() {
        print("\(#function)")
        let controller : FlutterViewController = appDelegate?.window?.rootViewController as! FlutterViewController
        let channel = FlutterMethodChannel(name: "app.flutter.dev/ScreenRecord",
                                           binaryMessenger: controller.binaryMessenger)
        channel.setMethodCallHandler({
            (call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
            // This method is invoked on the UI thread.
            // Handle battery messages.
            if call.method == "preventScreenRecord" {
                self.preventScreenRecord()
            } else if call.method == "preventScreenRecordDispose" {
                self.preventScreenRecordDispose()
            } else {
                result(FlutterMethodNotImplemented)
            }
        })
    }
    var field: UITextField!
    func preventScreenRecord() {
        print("preventScreenRecord")
        if let keyWindow = UIApplication.shared.keyWindow {
            hideContentOnScreenCapture(isSecure: true, window: keyWindow)
        }
    }
    func preventScreenRecordDispose() {
        print("preventScreenRecordDispose")
        if let keyWindow = UIApplication.shared.keyWindow {
            hideContentOnScreenCapture(isSecure: false, window: keyWindow)
        }
    }
    func hideContentOnScreenCapture(isSecure: Bool, window: UIWindow) {
        DispatchQueue.main.async {
            if isSecure {
                self.field = UITextField()
                self.field.isSecureTextEntry = true
                window.addSubview(self.field)
                self.field.centerYAnchor.constraint(equalTo: window.centerYAnchor).isActive = true
                self.field.centerXAnchor.constraint(equalTo: window.centerXAnchor).isActive = true
                window.layer.superlayer?.addSublayer(self.field.layer)
                self.field.layer.sublayers?.first?.addSublayer(window.layer)
            }
            else {
                if self.field != nil {
                    self.field.isSecureTextEntry = false
                }
            }
        }
    }    
}