It's not possible from Dart using the webview_flutter plugin.
However, you can use 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.
It implements methods to pause/resume the WebView.
For Android, you can use InAppWebViewController.android.pause and InAppWebViewController.android.resume to pause and resume WebView.
You should implement WidgetsBindingObserver in your Widget and check AppLifecycleState state through didChangeAppLifecycleState() method.
If you need to pause/resume also JavaScript execution you can use InAppWebViewController.pauseTimers/InAppWebViewController.resumeTimers methods.
Here is an example with a YouTube URL:
import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter_inappwebview/flutter_inappwebview.dart';
Future main() async {
WidgetsFlutterBinding.ensureInitialized();
runApp(MyApp());
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => new _MyAppState();
}
class _MyAppState extends State<MyApp> with WidgetsBindingObserver {
InAppWebViewController webView;
@override
void initState() {
WidgetsBinding.instance.addObserver(this);
super.initState();
}
@override
void dispose() {
WidgetsBinding.instance.removeObserver(this);
super.dispose();
}
@override
void didChangeAppLifecycleState(AppLifecycleState state) {
print('state = $state');
if (webView != null) {
if (state == AppLifecycleState.paused) {
webView.pauseTimers();
if (Platform.isAndroid) {
webView.android.pause();
}
} else {
webView.resumeTimers();
if (Platform.isAndroid) {
webView.android.resume();
}
}
}
}
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('InAppWebView Example'),
),
body: Container(
child: Column(children: <Widget>[
Expanded(
child: InAppWebView(
initialUrl: "https://www.youtube.com/watch?v=NfNdXgJZfFo",
initialHeaders: {},
initialOptions: InAppWebViewGroupOptions(
crossPlatform: InAppWebViewOptions(
debuggingEnabled: true,
),
),
onWebViewCreated: (InAppWebViewController controller) {
webView = controller;
},
onLoadStart: (InAppWebViewController controller, String url) {},
onLoadStop: (InAppWebViewController controller, String url) {},
))
])),
),
);
}
}