delegate.m didFinishLaunchingWithOptions

        GeneratedPluginRegistrant.register(with: self)
          let registrar = self.registrar(forPlugin: "FlutterIosPay")!
          let factory = MyPlatformViewFactory(messenger: registrar.messenger())
          registrar.register(factory, withId: "FlutterIosPay/custom_platform_view")
          Flutter2OCBridge.register(with: registrar);

MyPlatformViewFactory

import UIKit
import Flutter
class MyPlatformViewFactory: NSObject, FlutterPlatformViewFactory {
     var messenger: FlutterBinaryMessenger
    init(messenger:FlutterBinaryMessenger) {
       self.messenger = messenger
       super.init()
     }
    func create(withFrame frame: CGRect, viewIdentifier viewId: Int64, arguments args: Any?) -> FlutterPlatformView {
        return MyPlatformView(frame: frame, viewIdentifier: viewId, arguments: args, binaryMessenger: self.messenger)
     }
     
     func createArgsCodec() -> FlutterMessageCodec & NSObjectProtocol {
       return FlutterStandardMessageCodec.sharedInstance()
     }
    
  }

MyPlatformView

import Flutter
import UIKit

class MyPlatformView: NSObject, FlutterPlatformView {
    var _view: UIView
    
    init(frame: CGRect, viewIdentifier: Int64, arguments: Any?, binaryMessenger: FlutterBinaryMessenger) {
        print("---------------->webview frame:\(frame) <-------------");
        _view = UIView(frame: frame)
        if arguments is NSDictionary {
            let dict = arguments as! NSDictionary
            if(dict["page"] as! String == "portalWebView"){
                let tView = PortalWebView(frame: frame)
                tView.transferDataDic = arguments as! [AnyHashable : Any];
                _view = tView;
            }
            
            
        }else{
           
        }
        
    }

    func view() -> UIView {
              
        return _view
    }
}