How to close a web view from different screen using bloc in Flutter?

To close a web view from a different screen using the BLoC pattern in Flutter, you can follow these steps:

1. Define an event in your BLoC class to trigger the closing of the web view. For example:

// WebViewBlocEvent.dart
abstract class WebViewBlocEvent {}

class CloseWebViewEvent extends WebViewBlocEvent {}

1. Add a corresponding state in your BLoC class to represent the state of the web view. This state will indicate whether the web view should be closed or not. For example:

// WebViewBlocState.dart
abstract class WebViewBlocState {}

class WebViewOpenState extends WebViewBlocState {}

class WebViewClosedState extends WebViewBlocState {}

1. Implement the BLoC class that handles the events and manages the state:

// WebViewBloc.dart
import 'dart:async';

class WebViewBloc {
  final _eventStreamController = StreamController();
  final _stateStreamController = StreamController();

  StreamSink get eventSink => _eventStreamController.sink;
  Stream get stateStream => _stateStreamController.stream;

  WebViewBloc() {
    _eventStreamController.stream.listen(_handleEvent);
  }

  void _handleEvent(WebViewBlocEvent event) {
    if (event is CloseWebViewEvent) {
      _closeWebView();
    }
  }

  void _closeWebView() {
    _stateStreamController.sink.add(WebViewClosedState());
  }

  void dispose() {
    _eventStreamController.close();
    _stateStreamController.close();
  }
}

1. In the screen where you want to trigger the closing of the web view, access the BLoC instance and add the corresponding event:

// CloseWebViewScreen.dart
import 'package:flutter/material.dart';
import 'WebViewBloc.dart';

class CloseWebViewScreen extends StatelessWidget {
  final WebViewBloc webViewBloc;

  CloseWebViewScreen({required this.webViewBloc});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Close WebView'),
      ),
      body: Center(
        child: ElevatedButton(
          child: Text('Close WebView'),
          onPressed: () {
            webViewBloc.eventSink.add(CloseWebViewEvent());
            Navigator.pop(context); // Close the current screen
          },
        ),
      ),
    );
  }
}

1. In the screen where the web view is displayed, listen to the BLoC's state changes and handle the web view visibility accordingly:

// WebViewScreen.dart
import 'package:flutter/material.dart';
import 'WebViewBloc.dart';

class WebViewScreen extends StatefulWidget {
  final WebViewBloc webViewBloc;

  WebViewScreen({required this.webViewBloc});

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

class _WebViewScreenState extends State {
  @override
  void initState() {
    super.initState();
    widget.webViewBloc.stateStream.listen(_handleStateChange);
  }

  void _handleStateChange(WebViewBlocState state) {
    if (state is WebViewClosedState) {
      Navigator.pop(context); // Close the web view screen
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Web View Screen'),
      ),
      body: Container(
        // Build your web view widget here
      ),
    );
  }

  @override
  void dispose() {
    widget.webViewBloc.dispose();
    super.dispose();
  }
}

1. In your app's main file or wherever you create your BLoC instances, create the WebViewBloc and pass it to both the CloseWebViewScreen and WebViewScreen:

// main.dart
import 'package:flutter/material.dart';
import 'WebViewBloc.dart';
import 'CloseWebViewScreen.dart';
import 'WebViewScreen.dart';

void main() {
  final webViewBloc = WebViewBloc();

  runApp(MyApp(webViewBloc: webViewBloc));
}

class MyApp extends StatelessWidget {
  final WebViewBloc webViewBloc;

  MyApp({required this.webViewBloc});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: CloseWebViewScreen(webViewBloc: webViewBloc),
      routes: {
        '/webView': (context) => WebViewScreen(webViewBloc: webViewBloc),
      },
    );
  }
}

Now, when you navigate to the CloseWebViewScreen and press the "Close WebView" button, it will trigger the closing event, close the web view screen, and return to the previous screen.