Flutter 2.2 Recap

Google IO run in May 2021, and we met Flutter 2.2 announcement with fresh updates. More details come with the well known official blog, by this post let’s try to extract takeaways.

Takeaways

• Flutter progresses through the path to become the multi-platform solution for any kind of device with a screen
• Big names in contributors & adopters list: Canonical Ubuntu, Microsoft, Sony, Samsung, Toyota, BMW, Adobe
• Platform Adaptive App term is used to centralize the approaches: Building Adaptive Apps. As a part of it, Material Large Screen Guidance is addressed as well
• Windows UWP is introduced (alpha) – additionally to Mobile & Web in stable, Windows, macOS, Linux in beta. More about here
• Samsung starts adding Tizen support
• Adobe updates XD support for Flutter 2
• Growing popularity. 200K apps on Play Market in Flutter
• Invertase significantly improves FlutterFire plugins (Firebase integration) moving several as stable with Null Safety
• Null Safety is adopted by 93% of top-500 packages

Mobile

Flutter 2.2 brings iOS Metal shaders pre-compilations ^preview, improved Cupertino animations smoothness, iOS App Deltas for faster dev build install, and Android Deferred components ^preview downloaded “lazily” on-demand. 

Web

JS ServiceWorker caching is fixed: updates in background are gracefully handled, without the manual page refresh now. For existing projects, flutter create re-run is needed to adopt the fix.

Example of adopted fix against Firebase Hosting Cache Control

Both HTML and CanvasKit renderers have got SVG support, Font Feature Settings and Line Metrics.

More gaps with Mobile platforms are covered with semantic nodes support including visualization for debugging.

Layout DevTools for Web support is the same as for Mobile.

Desktops

Scrollbars are automatically visible on platforms where applicable – as expected on desktops.

Now UWP target is available (as alpha via DEV channel).

Flutter build and run are possible on Linux ARM64 devices.

Others

Improved keystrokes as a text editing actions handling towards native look & feel. Rich text with TextSpans now gets the ability to customize mouse cursor.

Responsiveness and support of Large Screens Guidance are added to the docs. Also more Material Icons are added.

Dart Platform

Dart has got own announcement with the v2.13 release.

No much updates to the Dart 2.12 where long-awaited Null Safety was released, just as a reminder – flutter create and dart create use new options and enforce Null Safety by default and dart pub outdated tool helps to analyze dependency status.

Review the guide on migrating to Null Safety.

Typedef is added to shorten complex types declaration. Post overview.

Foreign Function Interface (FFI) Dart-to-C interop has got some improvements like struct inline arrays and packed structs support.

Server-side Dart receives updated verified Docker images which are recommended for Google Cloud.