A11y Linter — Flutter accessibility lint rules

This package provides a set of custom lint rules to help catch common accessibility issues in Flutter code. The rules are implemented as a custom_lint plugin so they can be run in CI or picked up by IDEs that support the custom_lint runner.

Quick start

1. Add the linter to your project's dev_dependencies (use the version that matches this package or a released version):

dev_dependencies:
  a11y_linter: ^0.1.0
  custom_lint: any

2. Enable the custom_lint analyzer plugin in your analysis_options.yaml:

analyzer:
  plugins:
	- custom_lint

3. Install packages and run the custom linter. From your project root run:

# for Dart projects
dart pub get
dart run custom_lint

# for Flutter projects
flutter pub get
flutter pub run custom_lint

Editors that support the Dart analysis server (for example VS Code or IntelliJ/Android Studio) will pick up the lint results while custom_lint is running. You can also run flutter analyze / dart analyze to see lint results once the plugin is active.

Available rules

• missing_semantics_label

  • Ensures Icon, Image, and ImageIcon provide an accessible label via semanticLabel, are wrapped with Semantics(label: ...), or are marked decorative with ExcludeSemantics. Also checks clickable widgets with icon-only content (e.g. IconButton) for a tooltip or an accessible label. See Non-textual elements and Decorative elements of the Baseflow Accessibility Guidelines.

• missing_focus_indicator

  • Flags interactive widgets that do not expose a visible focus indicator. Suggests providing focusColor or a FocusNode (or wrapping with ExcludeSemantics if intentionally non-interactive). See Focus indication of the Baseflow Accessibility Guidelines.

• missing_persistent_input_label

  • Ensures input widgets (e.g. TextField, TextFormField) expose a persistent label via InputDecoration(labelText: ...) rather than relying solely on placeholder/hint text. See Form validation & labels of the Baseflow Accessibility Guidelines.

• orientation_lock

  • Detects calls that lock device orientation (e.g. SystemChrome .setPreferredOrientations) and warns that orientation locking should be avoided for accessibility. See Screen orientation of the Baseflow Accessibility Guidelines.

• insufficient_color_contrast

  • Statically checks color literals for text, icons and other foreground elements against nearby background colors and reports when contrast is below the WCAG AA thresholds (4.5:1 for normal text, 3:1 for large text). Note: only statically determinable colors (literals, Colors.*, etc.) are checked; theme colors and runtime expressions are skipped. See Color contrast of the Baseflow Accessibility Guidelines.