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Flutter_Documentation

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onPressed: () {
// Navigate to the second screen using a named route.
Navigator.pushNamed(context, '/second');
// Immediately show a dialog upon loading the second screen.
Navigator.push(
context,
PageRouteBuilder(
barrierDismissible: true,
opaque: false,
pageBuilder: (_, anim1, anim2) => const MyDialog(),
),
);
},
),
),
);
}
}<code_end>
<topic_end>
<topic_start>
The ScrollController is attached to multiple scroll views
This error can occur when multiple scrolling
widgets (such as ListView) appear on the
screen at the same time. It’s more likely for
this error to occur on a web or desktop app,
than a mobile app since it’s rare to encounter
this scenario on mobile.For more information and to learn how to fix,
check out the following video on
PrimaryScrollController:<topic_end>
<topic_start>
References
To learn more about how to debug errors,
especially layout errors in Flutter,
check out the following resources:
<topic_end>
<topic_start>Handling errors in Flutter
The Flutter framework catches errors that occur during callbacks
triggered by the framework itself, including errors encountered
during the build, layout, and paint phases. Errors that don’t occur
within Flutter’s callbacks can’t be caught by the framework,
but you can handle them by setting up an error handler on the
PlatformDispatcher.All errors caught by Flutter are routed to the
FlutterError.onError handler. By default,
this calls FlutterError.presentError,
which dumps the error to the device logs.
When running from an IDE, the inspector overrides this
behavior so that errors can also be routed to the IDE’s
console, allowing you to inspect the
objects mentioned in the message.info Note
Consider calling FlutterError.presentError
from your custom error handler in order to see
the logs in the console as well.When an error occurs during the build phase,
the ErrorWidget.builder callback is
invoked to build the widget that is used
instead of the one that failed. By default,
in debug mode this shows an error message in red,
and in release mode this shows a gray background.When errors occur without a Flutter callback on the call stack,
they are handled by the PlatformDispatcher’s error callback. By default,
this only prints errors and does nothing else.You can customize these behaviors,
typically by setting them to values in
your void main() function.Below each error type handling is explained. At the bottom
there’s a code snippet which handles all types of errors. Even
though you can just copy-paste the snippet, we recommend you
to first get acquainted with each of the error types.<topic_end>
<topic_start>
Errors caught by Flutter
For example, to make your application quit immediately any time an
error is caught by Flutter in release mode, you could use the
following handler:
<code_start>import 'dart:io';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
void main() {
FlutterError.onError = (details) {
FlutterError.presentError(details);
if (kReleaseMode) exit(1);
};
runApp(const MyApp());
}
// rest of `flutter create` code...<code_end>
info Note
The top-level kReleaseMode constant indicates
whether the app was compiled in release mode.This handler can also be used to report errors to a logging service.
For more details, see our cookbook chapter for
reporting errors to a service.<topic_end>
<topic_start>
Define a custom error widget for build phase errors
To define a customized error widget that displays whenever
the builder fails to build a widget, use MaterialApp.builder.
<code_start>class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
builder: (context, widget) {
Widget error = const Text('...rendering error...');
if (widget is Scaffold || widget is Navigator) {
error = Scaffold(body: Center(child: error));
}
ErrorWidget.builder = (errorDetails) => error;