Accessibility and Internationalization

Accessibility ensures people with diverse abilities can perceive, understand, navigate, and interact with your app. Key areas to address are semantics for UI elements, correct focus order and keyboard navigation, readable content under large text scale, adequate contrast, and support for assistive technologies like screen readers. Treat accessibility as core design work, not an afterthought.

• Use built-in semantic-aware widgets such as TextButton, IconButton, ListTile, and Text to provide baseline accessibility.
• Add semantic information using the Semantics widget for custom or decorative widgets.
• Use meaningful labels for interactive elements, concise hints for complex controls, and role annotations for groups of controls.

• Support TalkBack on Android and VoiceOver on iOS by ensuring widgets expose appropriate semantics.
• Announce important dynamic changes using SemanticsService.announce to inform screen reader users when content updates asynchronously.
• Keep announcements short and specific and avoid redundant or noisy announcements during frequent updates.

• Use Focus, FocusScope, and FocusNode to control keyboard and accessibility focus for forms and custom controls.
• Ensure logical focus order that matches visual order and supports tab navigation.
• Provide clear visual focus indicators for keyboard users and avoid traps where focus cannot move away from a modal.

• Respect user text scaling preferences via MediaQuery.textScaleFactor and test layouts at large scale factors to avoid clipping or overlap.
• Use relative sizing from TextTheme and avoid hard-coding font sizes.
• Ensure color contrast meets WCAG guidelines. Use accessible color tokens and test contrast ratios for primary text, icons, and interactive controls.
• Avoid conveying information by color alone; provide text or icon alternatives.

• Make interactive touch targets at least 44x44 logical pixels to accommodate diverse motor abilities.
• Provide spacing between tappable controls and avoid dense clusters.
• For gesture-only controls, provide alternative explicit controls or affordances accessible through semantics.

• Externalize user-facing strings into ARB or JSON resource files and load them via the intl package or Flutter localization tools.
• Use code generation tools to produce strongly typed localization accessors for safety.
• Localize not only text but also date, number, currency formatting, pluralization, and right-to-left layout where applicable.

• Use ICU message syntax or intl helpers for pluralization and gender-sensitive text.
• Format numbers, currencies, and dates with locale-aware APIs.
• Avoid concatenating localized fragments that may produce incorrect grammar in other languages.

• Support RTL languages by using Directionality and setting textDirection from the current locale or MaterialApp automatic handling.
• Verify mirrored layouts for icons, padding, and alignment when switching to RTL.
• Test both LTR and RTL flows including navigation, animations, and custom painting.

• Provide locale-specific assets when text is embedded in images or cultural variants are necessary.
• Use AssetBundle variants or runtime selection based on Locale to pick appropriate images.
• Avoid embedding text in images when possible and prefer overlays so translations remain editable.

• Test with real assistive technologies on devices: TalkBack and VoiceOver.
• Run automated accessibility checks using semantic tree inspections and accessibility testing tools where available.
• Test localized builds on actual devices or emulators for layout and string overflow issues.
• Include accessibility tests in CI where feasible, such as checking that critical interactive widgets have semantics and labels.

• Maintain a localization guide in the repository with instructions for adding locales and translators workflow.
• Keep a glossary of terms and context notes for translators to avoid ambiguity.
• Use continuous localization workflows or translation management systems for scale.