HTML WIdget

html_widget.dart

import 'dart:html' as html;
import 'dart:ui' as ui;
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';

final Map<int, HtmlElementWidgetState> _widgetRef = {};

abstract class HtmlElementWidget extends StatefulWidget {
  const HtmlElementWidget({Key? key}) : super(key: key);

  html.HtmlElement createHtmlElement(BuildContext context);

  @override
  HtmlElementWidgetState createState() => HtmlElementWidgetState();
}

class HtmlElementWidgetState<T extends HtmlElementWidget> extends State<T> {
  static bool _registered = false;

  @override
  void initState() {
    super.initState();
    if (!_registered && kIsWeb) {
      _registerPlatformView();
      _registered = true;
    }
  }

  html.HtmlElement createHtmlElement(BuildContext context) {
    return widget.createHtmlElement(context);
  }

  void _registerPlatformView() {
    ui.platformViewRegistry.registerViewFactory(
      'HtmlElementWidget',
      (int viewId) {
        final state = _widgetRef[viewId];
        assert(state != null, 'State should not be null');
        return state!.createHtmlElement(context);
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return PlatformViewLink(
      viewType: 'HtmlElementWidget',
      onCreatePlatformView: (PlatformViewCreationParams params) {
        _widgetRef[params.id] = this;
        final controller = _HtmlElementViewController(params);
        controller.initialize().then((_) {
          params.onPlatformViewCreated(params.id);
        });
        return controller;
      },
      surfaceFactory: (context, controller) {
        return PlatformViewSurface(
          controller: controller,
          gestureRecognizers: <Factory<OneSequenceGestureRecognizer>>{},
          hitTestBehavior: PlatformViewHitTestBehavior.opaque,
        );
      },
    );
  }
}

class _HtmlElementViewController extends PlatformViewController {
  _HtmlElementViewController(this.params);

  final PlatformViewCreationParams params;
  bool _initialized = false;

  @override
  int get viewId => params.id;

  Future<void> initialize() async {
    await SystemChannels.platform_views.invokeMethod<void>(
      'create',
      {'id': viewId, 'viewType': params.viewType},
    );
    _initialized = true;
  }

  @override
  Future<void> clearFocus() async {
    
  }

  @override
  Future<void> dispatchPointerEvent(PointerEvent event) async {
    
  }

  @override
  Future<void> dispose() async {
    if (_initialized) {
      await SystemChannels.platform_views.invokeMethod<void>('dispose', viewId);
    }
  }
}