Cannot pass arguments to Flutter Platform View Swift `UiKitView`

Question

I'm using Platform View to integrate native views in my Flutter app. I successfully integrated Android view but I'm facing issue in iOS view. I followed EXACTLY the instruction in Flutter docs: Hosting native iOS views in your Flutter app with Platform Views, but my arguments somehow cannot pass to Swift native.

Dart code:

UiKitView(
  viewType: '<platform-view-type>',
  layoutDirection: ui_import.TextDirection.ltr,
  creationParams: {"num": 1, "text": "example"}, // my argument
  creationParamsCodec: StandardMessageCodec(),
)

Swift code, FLNativeView.swift:

class FLNativeViewFactory: NSObject, FlutterPlatformViewFactory {
    private var messenger: FlutterBinaryMessenger

    init(messenger: FlutterBinaryMessenger) {
        self.messenger = messenger
        super.init()
    }

    func create(
        withFrame frame: CGRect,
        viewIdentifier viewId: Int64,
        arguments args: Any?
    ) -> FlutterPlatformView {
        return FLNativeView( // <---- breakpoint here, but args parameter is nil
            frame: frame,
            viewIdentifier: viewId,
            arguments: args,
            binaryMessenger: messenger)
    }
}

My AppDelegate.swift:

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        GeneratedPluginRegistrant.register(with: self)
        
        weak var registrar = self.registrar(forPlugin: "plugin-name")
        
        let factory = FLNativeViewFactory(messenger: registrar!.messenger())
        self.registrar(forPlugin: "<plugin-name>")!.register(
            factory,
            withId: "<platform-view-type>")
        
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
}

My flutter doctor:

[✓] Flutter (Channel stable, 3.7.8, on macOS 13.4 22F66 darwin-arm64, locale en-VN)
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 14.1)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2022.1)
[✓] VS Code (version 1.78.2)
[✓] Connected device (3 available)
[✓] HTTP Host Availability

P/s: The reason why I have to working on native views is that PDF functionality of Flutter is not as "full" as Kotlin/Swift.

I followed EXACTLY the instruction in Flutter docs and also look through other Flutter posts, Android works but iOS doesn't.

Answer 1

Oh damn I figure it out! The problem is lack of documentation. The issue has raised in GitHub: https://github.com/flutter/flutter/issues/28124. In my FLNativeViewFactory, add this function:

    public func createArgsCodec() -> FlutterMessageCodec & NSObjectProtocol {
          return FlutterStandardMessageCodec.sharedInstance()
    }

Then it WORKS!