What’s New in Flutter 2.2 – Key Updates and Features

Flutter 2.2 focuses on polishing and optimizing the framework, engine, and plugin ecosystem, delivering performance improvements for iOS ( iOS的性能改进) and Android ( Android的延迟组件), as well as service‑worker updates for Flutter web.

Developers can upgrade by switching to the stable channel or following the installation guide at flutter.dev/docs/get‑st…. The release merges 2,456 PRs and closes 3,105 issues, with top contributors highlighted.

Flutter 2.2 Stable Updates

This version adds new Material icons, TextSpan text handling, scrollbar behavior, and mouse‑cursor support, all built on the new Dart version.

Dart 2.13

Dart 2.13 introduces type aliases for functions and classes, and a deprecation‑based class rename mechanism.

typedef ValueChanged<T> = void Function(T value);

typedef StringList = List<String>;

@Deprecated("Use NewClassName instead")
typedef OldClassName<T> = NewClassName<T>;

To enable type aliases, set the SDK constraint in pubspec to ">=2.13.0 <3.0.0".

environment:
  sdk: ">=2.13.0 <3.0.0"

Flutter Web Updates

The new service worker improves caching and prevents duplicate main.dart.js downloads. Enabling it requires regenerating index.html via flutter create.

Web rendering improvements include FontFeature support, Canvas API text rendering, and added ShaderMask and computeLineMetrics for both HTML and CanvasKit.

Accessibility enhancements introduce a SemanticsNode tree that maps to the DOM, with improved focus handling for transformed widgets.

$ flutter run -d chrome --profile \
  --dart-define=FLUTTER_WEB_DEBUG_SHOW_SEMANTICS=true

iOS Page Transitions and Incremental Installation

Rendering time for iOS page transitions is reduced by 75%, and incremental iOS installs cut update installation time by 40%.

Platform‑Adaptive Applications

Guidance for building apps that adapt to multiple platforms, input types, and navigation patterns is provided, with examples like Flokk and Folio.

More Material Icons

Two PRs add over 7,000 Material icons, searchable at fonts.google.com/icons.

Improved Text Handling

Custom text actions allow special handling of keys such as Enter, Ctrl+Enter, and backspace. Example code demonstrates clearing a TextField with custom shortcuts.

import 'package:flutter/material.dart';

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

class App extends StatelessWidget {
  @override
  Widget build(BuildContext context) => MaterialApp(
        title: 'Flutter Text Editing Fun',
        home: HomePage(),
      );
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) => Scaffold(
        body: Column(
          children: [
            TextField(),
            OutlinedButton(onPressed: () {}, child: const Text('Press Me')),
          ],
        ),
      );
}

Further examples show binding delete, backspace, and left‑arrow keys to a custom ClearIntent action.

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) => MaterialApp(
        title: 'Flutter TextField Key Binding Demo',
        home: Scaffold(body: UnforgivingTextField()),
      );
}

class UnforgivingTextField extends StatefulWidget {
  @override
  State<UnforgivingTextField> createState() => _UnforgivingTextFieldState();
}

class _UnforgivingTextFieldState extends State<UnforgivingTextField> {
  late TextEditingController controller;

  @override
  void initState() {
    super.initState();
    controller = TextEditingController();
  }

  @override
  Widget build(BuildContext context) => Shortcuts(
        shortcuts: {
          LogicalKeySet(LogicalKeyboardKey.arrowLeft): const ClearIntent(),
          LogicalKeySet(LogicalKeyboardKey.delete): const ClearIntent(),
          LogicalKeySet(LogicalKeyboardKey.backspace): const ClearIntent(),
        },
        child: Actions(
          actions: {ClearIntent: ClearAction(controller: controller)},
          child: Center(child: TextField(controller: controller)),
        ),
      );
}

class ClearIntent extends Intent { const ClearIntent(); }

class ClearAction extends Action<ClearIntent> {
  ClearAction({required this.controller});
  final TextEditingController controller;
  @override
  Object? invoke(covariant ClearIntent intent) => controller.clear();
}

Automatic Scrollbar Behavior

Scrollbars now appear automatically on desktop when needed; developers can customize via ScrollBarTheme or ScrollBehavior.

Mouse Cursor on TextSpan

TextSpans with gesture recognizers now automatically show a pointer cursor, and support onEnter, onExit, and mouseCursor.

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:url_launcher/url_launcher.dart' as urlLauncher;

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

class App extends StatelessWidget {
  static const title = 'Flutter App';
  @override
  Widget build(BuildContext context) => MaterialApp(
        title: title,
        home: HomePage(),
      );
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) => Scaffold(
        appBar: AppBar(title: Text(App.title)),
        body: Center(
          child: RichText(
            text: TextSpan(
              style: TextStyle(fontSize: 48),
              children: [
                TextSpan(text: 'This is not a link, ', style: TextStyle(color: Colors.black)),
                TextSpan(
                  text: 'but this is',
                  style: TextStyle(color: Colors.blue),
                  recognizer: TapGestureRecognizer()
                    ..onTap = () => urlLauncher.launch('https://flutter.dev'),
                ),
              ],
            ),
          ),
        ),
      );
}

Preview Features in Flutter 2.2

Includes iOS shader‑compiler performance improvements, Android deferred components, desktop updates, and ARM64 Linux host support.

iOS Shader‑Compilation Improvements

Pre‑warming shaders for Metal reduces jank, though it increases app size and startup latency.

Android Deferred Components

Allows downloading code and assets on demand, reducing initial install size (e.g., a 46% reduction in Flutter Gallery).

Flutter Windows UWP Alpha

Enables building Flutter apps for Windows UWP, including Xbox, via the dev channel.

$ flutter channel dev
$ flutter upgrade
$ flutter config --enable-windows-uwp-desktop

$ flutter create uwp_fun
$ cd uwp_fun
$ flutter pub get
$ flutter run -d winuwp

ARM64 Linux Support

Contributed by Sony engineer Hidenori Matsubayashi, allowing Flutter builds on ARM64 Linux machines.

Ecosystem and Tooling Updates

Flutter Favorite now includes 24 new plugins, many migrated to null safety. FlutterFire adds Firebase App Check support and type‑safe APIs. DevTools gains memory‑tracking improvements and a new Provider tab. IDE plugins for VS Code and Android Studio receive refactoring and stack‑trace features. DartPad introduces a guided workshop UI.

Community Focus: FlutterFlow

FlutterFlow is a low‑code, web‑based design tool that outputs Flutter code and integrates with Firebase.

Breaking Changes

Removed deprecated binary messages ( BinaryMessages) and the TypeMatcher class.

Summary

The Flutter team thanks the community for the continued growth, noting that over one‑eighth of new Play Store apps are built with Flutter, with more than 200,000 Flutter apps already published.