Webview makes my phone unresponse after turning off screen

[brvinodh]

Steps to Reproduce

Im using Android 10, oneplus7 pro phone(upgraded to android 10 recently).
When I create a very basic flutter app using webview and debug/install release on mobile.
I get to see the application with the URL loaded on mobile. However when i turn off screen/lock phone with the app still running/foreground.

My phone hangs with different types of behaviours
a. On pressing turn on/lock screen button(power button), the camera pops up/out (face recognition unlock) but display is still blank, after waiting for 1 min or so the phone display is shown back.
b. Camera pops up/in I believe internally it gets unlocked, howeer display is still blank, phone then restarts.

1. Android 10 phone, (one plus 7 pro)
2. .Create a very basic webview app ex:

    return Scaffold(
     appBar: AppBar(
       // Here we take the value from the MyHomePage object that was created by
       // the App.build method, and use it to set our appbar title.
       title: Text(widget.title),
     ),
     body: WebView(initialUrl: "https://www.google.com",),
     floatingActionButton: FloatingActionButton(
       onPressed: _incrementCounter,
       tooltip: 'Increment',
       child: Icon(Icons.add),
     ), // This trailing comma makes auto-formatting nicer for build methods.
   );
   

3. Deploy the app on phone

Target Platform:
Target OS version/browser:
Devices:

Logs

flutter run --verbose
I believe may not be releavant

[ +641 ms] I/chromium( 4302): [INFO:CONSOLE(0)] "A cookie associated with a resource at http://google.com/ was set with `SameSite=None` but without `Secure`. A future release of Chrome will only deliver
cookies marked `SameSite=None` if they are also marked `Secure`. You can review cookies in developer tools under Application>Storage>Cookies and see more details at
https://www.chromestatus.com/feature/5633521622188032.", source: https://www.google.com/search?source=hp&ei=Yw3HXfvcLYfUvgTaz6CACg&q=hello+world+are+youvrunn (0)
[+3253 ms] W/IInputConnectionWrapper( 4302): requestCursorAnchorInfo on inactive InputConnection
[  +25 ms] W/IInputConnectionWrapper( 4302): getTextBeforeCursor on inactive InputConnection
[   +3 ms] W/IInputConnectionWrapper( 4302): getSelectedText on inactive InputConnection
[   +7 ms] W/IInputConnectionWrapper( 4302): getTextAfterCursor on inactive InputConnection
[   +1 ms] W/IInputConnectionWrapper( 4302): requestCursorAnchorInfo on inactive InputConnection
[ +388 ms] E/InputMethodManager( 4302): b/117267690: Failed to get fallback IMM with expected displayId=4 actual IMM#displayId=0 view=io.flutter.plugins.webviewflutter.InputAwareWebView{ca464e0 VFEDHVC........ID 0,0-1440,1641}
[ +136 ms] V/ViewRootImpl( 4302): The specified message queue synchronization  barrier token has not been posted or has already been removed

flutter doctor -v
[√] Flutter (Channel dev, v1.10.15, on Microsoft Windows [Version 10.0.17134.1069], locale en-US)
• Flutter version 1.10.15 at C:\Data\flutter\flutter
• Framework revision fbabb26 (8 days ago), 2019-11-02 01:36:07 +0300
• Engine revision 8ea19b1
• Dart version 2.6.0 (build 2.6.0-dev.8.2 bbe2ac28c9)

[√] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
• Android SDK at C:\Users\vinodh\AppData\Local\Android\Sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-29, build-tools 29.0.2
• ANDROID_HOME = C:\Users\vinodh\AppData\Local\Android\Sdk
• ANDROID_SDK_ROOT = C:\Users\vinodh\AppData\Local\Android\Sdk
• Java binary at: C:\Program Files\Android\Android Studio1\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
• All Android licenses accepted.

[√] Android Studio (version 3.4)
• Android Studio at C:\Program Files\Android\Android Studio1
• Flutter plugin version 37.0.1
• Dart plugin version 183.6270
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[√] VS Code (version 1.39.2)
• VS Code at C:\Users\vinodh\AppData\Local\Programs\Microsoft VS Code
• Flutter extension version 3.6.0

[√] Connected device (1 available)
• GM1911 • bd4bb5d2 • android-arm64 • Android 10 (API 29)

[iapicca]

Hi @brvinodh
could you please provide your flutter run --verbose
performing the action that "hung" the phone
thank you

[brvinodh]

Hi @iapicca ,

Sorry, I had missed to add statement "flutter run --verbose" command in the above issue, however the last few lines of the flutter logs i had updated in the issue, same has been pasted below.

 +641 ms] I/chromium( 4302): [INFO:CONSOLE(0)] "A cookie associated with a resource at http://google.com/ was set with `SameSite=None` but without `Secure`. A future release of Chrome will only deliver
cookies marked `SameSite=None` if they are also marked `Secure`. You can review cookies in developer tools under Application>Storage>Cookies and see more details at
https://www.chromestatus.com/feature/5633521622188032.", source: https://www.google.com/search?source=hp&ei=Yw3HXfvcLYfUvgTaz6CACg&q=hello+world+are+youvrunn (0)
[+3253 ms] W/IInputConnectionWrapper( 4302): requestCursorAnchorInfo on inactive InputConnection
[  +25 ms] W/IInputConnectionWrapper( 4302): getTextBeforeCursor on inactive InputConnection
[   +3 ms] W/IInputConnectionWrapper( 4302): getSelectedText on inactive InputConnection
[   +7 ms] W/IInputConnectionWrapper( 4302): getTextAfterCursor on inactive InputConnection
[   +1 ms] W/IInputConnectionWrapper( 4302): requestCursorAnchorInfo on inactive InputConnection
[ +388 ms] E/InputMethodManager( 4302): b/117267690: Failed to get fallback IMM with expected displayId=4 actual IMM#displayId=0 view=io.flutter.plugins.webviewflutter.InputAwareWebView{ca464e0 VFEDHVC........ID 0,0-1440,1641}
[ +136 ms] V/ViewRootImpl( 4302): The specified message queue synchronization  barrier token has not been posted or has already been removed

Also wanted to highlight that the Phone does not hang when the App is being used; but when i have opened a flutter app which contains a webview and turn off the screen, [or switch to other apps (phone dialer, messager, etc)] . The phone hangs up after some time.

Please find the
sourceCode.zip source code which contains a simple webview

Also wanted to highlight that the flutter verbose does not give me any logs when the phone screen is off/or its in background.

Thank you.

[iapicca]

Hi @brvinodh
thank you for providing these information

[Pijulin]

@iapicca @iapicca same issue on MIUI 11 which based on Android 10

[brvinodh]

Hi @iapicca , Just checking if we have an update.. Thanks

[iapicca]

Hi @brvinodh @Pijulin
are you experiencing the issue with the last stable version of flutter and webview plugin?
thank you

[brvinodh]

Hi @iapicca ,

There has been no luck, its still the same case.. the phone screen is not turning on.

I created a simple app with webview inside it. Deployed in into an Android 10 mobile.
Open the app to see that its navigating to the required web page.

turned off the screen. waited for sometime (10 mins) . Now the phone screen does not turn on back.

Here is the sample code attached.

import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {


 final double topWidgetHeight = 200.0;
  final double avatarRadius = 50.0;

  @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.
      ),
      // 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 WebView(
          initialUrl: 'https://flutter.dev',
          javascriptMode: JavascriptMode.unrestricted,
          navigationDelegate: (NavigationRequest request) {
            if (request.url.startsWith('https://www.youtube.com/')) {
              print('blocking navigation to $request}');
              return NavigationDecision.prevent;
            }
            print('allowing navigation to $request');
            return NavigationDecision.navigate;
          },
          onPageStarted: (String url) {
            print('Page started loading: $url');
          },
          onPageFinished: (String url) {
            print('Page finished loading: $url');
          }
        );
      })
    );
  }  
}