How to take a screenshot of WebView (webview_flutter) which is implemented based on AndroidViews?

Question

I need to take a screenshot of WebView from webview_flutter, but it doesn't work.

I have an app which has to take a screenshot of WebView and then process it. I tried to do it using Screenshot package. I found this information https://github.com/fluttercommunity/flutter_webview_plugin/issues/181#issuecomment-497625384

From the link, I learned that it's impossible to do it through the Screenshot plugin.

Screenshot(
          controller: _screenshotController,
          child: WebView(
            initialUrl: widget._webUrl,
            onWebViewCreated:
                (WebViewController webViewController) {
              if (_controller.isCompleted == false)
                _controller.complete(webViewController);
            },
          ),
        );



  void takeScreenshot() {
    _screenshotController.capture().then(
            (File image) async {
          _screenshot = image;
        }
    );

When I take the screenshot I got transparent png image, whereas I would like to have capture of the WebView content

Answer 1

As I reported to this similar issue:

The webview_flutter plugin doesn't offer a way or a method to take the screenshot of the WebView. So, you can try my plugin flutter_inappwebview, which is a Flutter plugin that allows you to add inline WebViews or open an in-app browser window and has a lot of events, methods, and options to control WebViews.

To take a screenshot, you can use InAppWebViewController.takeScreenshot method, that takes a screenshot (in PNG format) of the WebView's visible viewport and returns a Uint8List.

Here is an example that takes a screenshot of the WebView when the page stops loading and shows an alert dialog with the corresponding screenshot image:

import 'dart:async';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter_inappwebview/flutter_inappwebview.dart';

Future main() async {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(new MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    super.initState();
  }

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(initialRoute: '/', routes: {
      '/': (context) => InAppWebViewExampleScreen(),
    });
  }
}

class InAppWebViewExampleScreen extends StatefulWidget {
  @override
  _InAppWebViewExampleScreenState createState() =>
      new _InAppWebViewExampleScreenState();
}

class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
  InAppWebViewController webView;
  Uint8List screenshotBytes;

  @override
  void initState() {
    super.initState();
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text("InAppWebView")),
        body: Container(
            child: Column(children: <Widget>[
          Expanded(
              child: InAppWebView(
            initialUrl: "https://github.com/flutter",
            initialHeaders: {},
            initialOptions: InAppWebViewGroupOptions(
              crossPlatform: InAppWebViewOptions(
                  debuggingEnabled: true),
            ),
            onWebViewCreated: (InAppWebViewController controller) {
              webView = controller;
            },
            onLoadStart: (InAppWebViewController controller, String url) {},
            onLoadStop: (InAppWebViewController controller, String url) async {
              screenshotBytes = await controller.takeScreenshot();
              showDialog(
                context: context,
                builder: (context) {
                  return AlertDialog(
                    content: Image.memory(screenshotBytes),
                  );
                },
              );
            },
          ))
        ])));
  }
}