bridge_webview_flutter 0.1.5

Add JsBridge to the WebView #

A Flutter plugin that provides a JsBridge on WebView widget.

On iOS the WebView widget is backed by a WKWebView; On Android the WebView widget is backed by a WebView.

This plugin based on the webview_flutter

Developers Preview Status #

To use this plugin on iOS you need to opt-in for the embedded views preview by adding a boolean property to the app's Info.plist file, with the key io.flutter.embedded_views_preview and the value YES.

Keyboard support - not ready for production use #

Keyboard support within webviews is experimental. The Android version relies on some low-level knobs that have not been well tested on a broad spectrum of devices yet, and therefore it is not recommended to rely on webview keyboard in production apps yet. See the webview-keyboard for known issues with keyboard input.

Setup #

iOS #

Opt-in to the embedded views preview by adding a boolean property to the app's Info.plist file with the key io.flutter.embedded_views_preview and the value YES.

Usage #

Add bridge_webview_flutter as a dependency in your pubspec.yaml file.

BridgeWebView(
    initialUrl: 'https://flutter.dev',
    javascriptMode: JavascriptMode.unrestricted,
    onWebViewCreated: (WebViewController webViewController) {
        _controller.complete(webViewController);
        webViewController.registerHandler("methodName", response: "r1", onCallBack: (callBackData) {
            print(callBackData.name); // handler name
            print(callBackData.data); // callback data ({'param': '1'})
        });
        webViewController.callHandler("methodName", data: "sendData", onCallBack: (callBackData) {
            print(callBackData.name); // handler name
            print(callBackData.data); // callback data (r2)
        });
    },
    onPageStarted: (String url) {
        print('Page started loading: $url');
    },
    onPageFinished: (String url) {
        print('Page finished loading: $url');
    }
)

Register a Flutter handler function so that js can call #

onWebViewCreated: (WebViewController webViewController) {
    _controller.complete(webViewController);
    webViewController.registerHandler("methodName", response: "r1", onCallBack: (callBackData) {
        print(callBackData.name); // handler name
        print(callBackData.data); // callback data ({'param': '1'})
    });
}

js can call this handler method "methodName" through:

WebViewJavascriptBridge.callHandler(
    'methodName'
    , {'param': '1'}
    , function(data) {
        // data is r1
    }
);

Register a JavaScript handler function so that flutter can call #

WebViewJavascriptBridge.registerHandler("methodName", function(data, responseCallback) {
    // data is 'sendData'
    responseCallback('r2');
});

flutter can call this js handler function "methodName" through:

onWebViewCreated: (WebViewController webViewController) {
    _controller.complete(webViewController);
    webViewController.callHandler("methodName", data: "sendData", onCallBack: (callBackData) {
        print(callBackData.name); // handler name
        print(callBackData.data); // callback data (r2)
    });
}

example/lib/main.dart

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// ignore_for_file: public_member_api_docs

import 'dart:async';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:bridge_webview_flutter/platform_interface.dart';
import 'package:bridge_webview_flutter/webview_flutter.dart';

void main() => runApp(MaterialApp(home: WebViewExample()));

const String kNavigationExamplePage = '''
<!DOCTYPE html><html>
<head><title>Navigation Delegate Example</title></head>
<body>
<p>
The navigation delegate is set to block navigation to the youtube website.
</p>
<ul>
<ul><a href="https://www.youtube.com/">https://www.youtube.com/</a></ul>
<ul><a href="https://www.google.com/">https://www.google.com/</a></ul>
</ul>
</body>
</html>
''';

class WebViewExample extends StatefulWidget {
  @override
  _WebViewExampleState createState() => _WebViewExampleState();
}

class _WebViewExampleState extends State<WebViewExample> {
  final Completer<WebViewController> _controller =
      Completer<WebViewController>();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Flutter WebView example'),
        // This drop down menu demonstrates that Flutter widgets can be shown over the web view.
        actions: <Widget>[
          NavigationControls(_controller.future),
          SampleMenu(_controller.future),
        ],
      ),
      // We're using a Builder here so we have a context that is below the Scaffold
      // to allow calling Scaffold.of(context) so we can show a snackbar.
      body: Builder(builder: (BuildContext context) {
        return BridgeWebView(
          initialUrl: 'https://flutter.dev',
          javascriptMode: JavascriptMode.unrestricted,
          onWebViewCreated: (WebViewController webViewController) {
            _controller.complete(webViewController);
            webViewController.registerHandler("methodName", response: "r1", onCallBack: (callBackData) {
              print(callBackData.name); // handler name
              print(callBackData.data); // callback data ({'param': '1'})
            });
            webViewController.callHandler("methodName", data: "sendData", onCallBack: (callBackData) {
              print(callBackData.name); // handler name
              print(callBackData.data); // callback data (r2)
            });
          },
          onPageStarted: (String url) {
            print('Page started loading: $url');
          },
          onPageFinished: (String url) {
            print('Page finished loading: $url');
          },
          gestureNavigationEnabled: true,
        );
      }),
      floatingActionButton: favoriteButton(),
    );
  }

  JavascriptChannel _toasterJavascriptChannel(BuildContext context) {
    return JavascriptChannel(
        name: 'Toaster',
        onMessageReceived: (JavascriptMessage message) {
          Scaffold.of(context).showSnackBar(
            SnackBar(content: Text(message.message)),
          );
        });
  }

  Widget favoriteButton() {
    return FutureBuilder<WebViewController>(
        future: _controller.future,
        builder: (BuildContext context,
            AsyncSnapshot<WebViewController> controller) {
          if (controller.hasData) {
            return FloatingActionButton(
              onPressed: () async {
                final String url = await controller.data.currentUrl();
                Scaffold.of(context).showSnackBar(
                  SnackBar(content: Text('Favorited $url')),
                );
              },
              child: const Icon(Icons.favorite),
            );
          }
          return Container();
        });
  }
}

enum MenuOptions {
  showUserAgent,
  listCookies,
  clearCookies,
  addToCache,
  listCache,
  clearCache,
  navigationDelegate,
}

class SampleMenu extends StatelessWidget {
  SampleMenu(this.controller);

  final Future<WebViewController> controller;
  final CookieManager cookieManager = CookieManager();

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<WebViewController>(
      future: controller,
      builder:
          (BuildContext context, AsyncSnapshot<WebViewController> controller) {
        return PopupMenuButton<MenuOptions>(
          onSelected: (MenuOptions value) {
            switch (value) {
              case MenuOptions.showUserAgent:
                _onShowUserAgent(controller.data, context);
                break;
              case MenuOptions.listCookies:
                _onListCookies(controller.data, context);
                break;
              case MenuOptions.clearCookies:
                _onClearCookies(context);
                break;
              case MenuOptions.addToCache:
                _onAddToCache(controller.data, context);
                break;
              case MenuOptions.listCache:
                _onListCache(controller.data, context);
                break;
              case MenuOptions.clearCache:
                _onClearCache(controller.data, context);
                break;
              case MenuOptions.navigationDelegate:
                _onNavigationDelegateExample(controller.data, context);
                break;
            }
          },
          itemBuilder: (BuildContext context) => <PopupMenuItem<MenuOptions>>[
            PopupMenuItem<MenuOptions>(
              value: MenuOptions.showUserAgent,
              child: const Text('Show user agent'),
              enabled: controller.hasData,
            ),
            const PopupMenuItem<MenuOptions>(
              value: MenuOptions.listCookies,
              child: Text('List cookies'),
            ),
            const PopupMenuItem<MenuOptions>(
              value: MenuOptions.clearCookies,
              child: Text('Clear cookies'),
            ),
            const PopupMenuItem<MenuOptions>(
              value: MenuOptions.addToCache,
              child: Text('Add to cache'),
            ),
            const PopupMenuItem<MenuOptions>(
              value: MenuOptions.listCache,
              child: Text('List cache'),
            ),
            const PopupMenuItem<MenuOptions>(
              value: MenuOptions.clearCache,
              child: Text('Clear cache'),
            ),
            const PopupMenuItem<MenuOptions>(
              value: MenuOptions.navigationDelegate,
              child: Text('Navigation Delegate example'),
            ),
          ],
        );
      },
    );
  }

  void _onShowUserAgent(
      WebViewController controller, BuildContext context) async {
    // Send a message with the user agent string to the Toaster JavaScript channel we registered
    // with the WebView.
    await controller.evaluateJavascript(
        'Toaster.postMessage("User Agent: " + navigator.userAgent);');
  }

  void _onListCookies(
      WebViewController controller, BuildContext context) async {
    final String cookies =
        await controller.evaluateJavascript('document.cookie');
    Scaffold.of(context).showSnackBar(SnackBar(
      content: Column(
        mainAxisAlignment: MainAxisAlignment.end,
        mainAxisSize: MainAxisSize.min,
        children: <Widget>[
          const Text('Cookies:'),
          _getCookieList(cookies),
        ],
      ),
    ));
  }

  void _onAddToCache(WebViewController controller, BuildContext context) async {
    await controller.evaluateJavascript(
        'caches.open("test_caches_entry"); localStorage["test_localStorage"] = "dummy_entry";');
    Scaffold.of(context).showSnackBar(const SnackBar(
      content: Text('Added a test entry to cache.'),
    ));
  }

  void _onListCache(WebViewController controller, BuildContext context) async {
    await controller.evaluateJavascript('caches.keys()'
        '.then((cacheKeys) => JSON.stringify({"cacheKeys" : cacheKeys, "localStorage" : localStorage}))'
        '.then((caches) => Toaster.postMessage(caches))');
  }

  void _onClearCache(WebViewController controller, BuildContext context) async {
    await controller.clearCache();
    Scaffold.of(context).showSnackBar(const SnackBar(
      content: Text("Cache cleared."),
    ));
  }

  void _onClearCookies(BuildContext context) async {
    final bool hadCookies = await cookieManager.clearCookies();
    String message = 'There were cookies. Now, they are gone!';
    if (!hadCookies) {
      message = 'There are no cookies.';
    }
    Scaffold.of(context).showSnackBar(SnackBar(
      content: Text(message),
    ));
  }

  void _onNavigationDelegateExample(
      WebViewController controller, BuildContext context) async {
    final String contentBase64 =
        base64Encode(const Utf8Encoder().convert(kNavigationExamplePage));
    await controller.loadUrl('data:text/html;base64,$contentBase64');
  }

  Widget _getCookieList(String cookies) {
    if (cookies == null || cookies == '""') {
      return Container();
    }
    final List<String> cookieList = cookies.split(';');
    final Iterable<Text> cookieWidgets =
        cookieList.map((String cookie) => Text(cookie));
    return Column(
      mainAxisAlignment: MainAxisAlignment.end,
      mainAxisSize: MainAxisSize.min,
      children: cookieWidgets.toList(),
    );
  }
}

class NavigationControls extends StatelessWidget {
  const NavigationControls(this._webViewControllerFuture)
      : assert(_webViewControllerFuture != null);

  final Future<WebViewController> _webViewControllerFuture;

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<WebViewController>(
      future: _webViewControllerFuture,
      builder:
          (BuildContext context, AsyncSnapshot<WebViewController> snapshot) {
        final bool webViewReady =
            snapshot.connectionState == ConnectionState.done;
        final WebViewController controller = snapshot.data;
        return Row(
          children: <Widget>[
            IconButton(
              icon: const Icon(Icons.arrow_back_ios),
              onPressed: !webViewReady
                  ? null
                  : () async {
                      if (await controller.canGoBack()) {
                        await controller.goBack();
                      } else {
                        Scaffold.of(context).showSnackBar(
                          const SnackBar(content: Text("No back history item")),
                        );
                        return;
                      }
                    },
            ),
            IconButton(
              icon: const Icon(Icons.arrow_forward_ios),
              onPressed: !webViewReady
                  ? null
                  : () async {
                      if (await controller.canGoForward()) {
                        await controller.goForward();
                      } else {
                        Scaffold.of(context).showSnackBar(
                          const SnackBar(
                              content: Text("No forward history item")),
                        );
                        return;
                      }
                    },
            ),
            IconButton(
              icon: const Icon(Icons.replay),
              onPressed: !webViewReady
                  ? null
                  : () {
                      controller.reload();
                    },
            ),
          ],
        );
      },
    );
  }
}

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:


dependencies:
  bridge_webview_flutter: ^0.1.5

2. Install it

You can install packages from the command line:

with Flutter:


$ flutter pub get

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:


import 'package:bridge_webview_flutter/platform_interface.dart';
import 'package:bridge_webview_flutter/webview_flutter.dart';
  
Popularity:
Describes how popular the package is relative to other packages. [more]
48
Health:
Code health derived from static analysis. [more]
100
Maintenance:
Reflects how tidy and up-to-date the package is. [more]
80
Overall:
Weighted score of the above. [more]
70
Learn more about scoring.

We analyzed this package on Jul 11, 2020, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.8.4
  • pana: 0.13.15
  • Flutter: 1.17.5

Analysis suggestions

Package does not support Flutter platform Linux

Because:

  • package:bridge_webview_flutter/platform_interface.dart that declares support for platforms: Android, iOS

Package does not support Flutter platform Web

Because:

  • package:bridge_webview_flutter/platform_interface.dart that declares support for platforms: Android, iOS

Package does not support Flutter platform Windows

Because:

  • package:bridge_webview_flutter/platform_interface.dart that declares support for platforms: Android, iOS

Package does not support Flutter platform macOS

Because:

  • package:bridge_webview_flutter/platform_interface.dart that declares support for platforms: Android, iOS

Package not compatible with SDK dart

Because:

  • bridge_webview_flutter that is a package requiring null.

Health suggestions

Format lib/platform_interface.dart.

Run flutter format to format lib/platform_interface.dart.

Format lib/src/webview_method_channel.dart.

Run flutter format to format lib/src/webview_method_channel.dart.

Format lib/webview_flutter.dart.

Run flutter format to format lib/webview_flutter.dart.

Maintenance issues and suggestions

Provide a file named CHANGELOG.md. (-20 points)

Changelog entries help developers follow the progress of your package. See the example generated by stagehand.

Dependencies

Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.2.0 <3.0.0
flutter 0.0.0
Transitive dependencies
collection 1.14.12 1.14.13
meta 1.1.8 1.2.2
sky_engine 0.0.99
typed_data 1.1.6 1.2.0
vector_math 2.0.8 2.1.0-nullsafety
Dev dependencies
flutter_driver
flutter_test
pedantic ^1.8.0