What's new in Flutter 3.22

Rename MaterialState to WidgetState

`MaterialState`, and its related APIs, have been moved out of the Material library and renamed to `WidgetState`.

Introduce new ColorScheme roles

New color roles in `ColorScheme` include seven tone-based surfaces and containers, and twelve accent colors for primary, secondary, and tertiary groups. This update deprecates three existing color roles: `background`, `onBackground`, and `surfaceVariant`. The `ColorScheme` constructed by the updated `ColorScheme.fromSeed` method now generates different values compared to the previous version, adapting to the Material Design 3 guidelines.

Nullable PageView.controller

If a controller isn't provided in the constructor, the `controller` member is `null`. This makes `PageView` and its `controller` property consistent with other widgets.

Rename MemoryAllocations to FlutterMemoryAllocations

Disposables in pure Dart projects can't use `MemoryAllocations` in Flutter. So, to be leak-trackable they need a Dart-only class. `MemoryAllocations` in Flutter is renamed to make the name available to a non-Flutter, Dart project.

Deprecated API removed after v3.19

In accordance with Flutter's Deprecation Policy, deprecated APIs that reached end of life after the 3.19 stable release have been removed.

Dropping support for Android KitKat

Flutter's minimum supported Android version is now Lollipop (API 21). Beginning with Flutter's 3.22 stable release, Flutter will no longer work on devices running Android KitKat (API 19).

- Fixes and issue on Windows when running certain commands, such as `flutter run` or `flutter build`, users get a lengthy crash message...

- Fixes an `EditableText` crash that occurs when a custom `TextEditingController` only implements the `TextEditingController` interface.

- Fixes a crash that occurs when rendering children in `TwoDimentionalViewport` using keep alive widgets (e.g InkWell).

- Fixes an issue where `const bool.fromEnvironment('dart.library.ffi')` is true and conditional import condition `dart.library.ffi` is...

- Fixes an issue where FFI calls with variadic arguments on MacOS Arm64 would mangle the arguments.

- [Impeller] Fixes rendering corruption when running on Intel mac simulators.

- [Impeller] Fixes an issue on iOS that causese paths to render incorrectly.

- [Impeller] Corrects and issue on iOs where coverage computation results in distored pixels in Impeller targets.

- [Impeller] Fixes and issue on iOS where flickering may be occur when translating a blurred rounded rectangle.

- [Impeller] Fixes a segfault on iOS when tessellating empty convex polygons.

- [Impeller] Fixes a rendering error on iOS when advanced blend is double scaled.

- Fixes an issue where Linux apps show visual corruption on some frames.

- Clarifies Flutter Fix log on how to update Kotlin Gradle Plugin that was introduced in Flutter 3.19.

- Fixes a bug in `flutter test` where `--flavor` wasn't considered when validating cached assets, causing the flavor-conditional asset...

- Fixes an issue on Web+Linux that prevents users from inputting data using the numpad.

- Fixes an issue where `DART_VM_OPTIONS` were not correctly parsed for standalone Dart executables created with `dart compile exe`.

- Fixes a bug in dart2wasm that can result in a runtime error that says `array.new_fixed()` has a constant larger than 10000.

- Adds support for `--enable-experiment` flag to `dart compile` wasm.

- Fixes an issue in dart2wasm compiler that can result in incorrect nullability of type parameter.

- Disallows `dart:ffi` imports in user code in dart2wasm as dart2wasm's currently only supports a small subset of `dart:ffi`.

- Fixes a platform view issue on android 14 when multiple activities are used and `onMemoryTrim` is called.

- Fixes an issue on iOS where users are unable to focus on a `TextField` or open the keyboard again after side pop from another screen.

- Fixes an issue in the `ColorScheme.fromSeed` method to respect the seed color even if the seed color is very bright.

- Adds a service extension that DevTools uses to support a "Track widget build counts" feature in DevTools 2.36.0.