Flutter AnimatedDefaultTextStyle Localization: Dynamic Typography, Text Transitions, and Style Inheritance
AnimatedDefaultTextStyle smoothly animates changes to text styling properties that are inherited by child Text widgets. Proper localization ensures that dynamic typography, theme transitions, and style changes work seamlessly across languages with different scripts and text directions. This guide covers comprehensive strategies for localizing AnimatedDefaultTextStyle widgets in Flutter.
Understanding AnimatedDefaultTextStyle Localization
AnimatedDefaultTextStyle widgets require localization for:
- Script-specific fonts: Different fonts for Arabic, Chinese, Devanagari scripts
- RTL text alignment: Proper alignment for right-to-left languages
- Dynamic font sizing: Adjusting sizes for languages with complex scripts
- Theme transitions: Smooth styling changes between light/dark modes
- Accessibility scaling: Respecting user font size preferences
- State-based styling: Indicating selection, focus, and error states
Basic AnimatedDefaultTextStyle with Locale Support
Start with a simple AnimatedDefaultTextStyle that adapts to locale:
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
class LocalizedAnimatedTitle extends StatefulWidget {
final bool isHighlighted;
final String text;
const LocalizedAnimatedTitle({
super.key,
required this.isHighlighted,
required this.text,
});
@override
State<LocalizedAnimatedTitle> createState() => _LocalizedAnimatedTitleState();
}
class _LocalizedAnimatedTitleState extends State<LocalizedAnimatedTitle> {
@override
Widget build(BuildContext context) {
final l10n = AppLocalizations.of(context)!;
final locale = Localizations.localeOf(context);
final isRtl = Directionality.of(context) == TextDirection.rtl;
// Determine font family based on script
final fontFamily = _getFontFamilyForLocale(locale);
// Adjust font size for complex scripts
final baseFontSize = _getBaseFontSizeForLocale(locale);
return Semantics(
header: true,
label: widget.isHighlighted
? l10n.highlightedTitleAccessibility(widget.text)
: widget.text,
child: AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 300),
curve: Curves.easeInOut,
style: TextStyle(
fontSize: widget.isHighlighted ? baseFontSize * 1.2 : baseFontSize,
fontWeight: widget.isHighlighted ? FontWeight.bold : FontWeight.normal,
color: widget.isHighlighted
? Theme.of(context).colorScheme.primary
: Theme.of(context).colorScheme.onSurface,
fontFamily: fontFamily,
letterSpacing: widget.isHighlighted ? 0.5 : 0,
height: _getLineHeightForLocale(locale),
),
textAlign: isRtl ? TextAlign.right : TextAlign.left,
child: Text(widget.text),
),
);
}
String? _getFontFamilyForLocale(Locale locale) {
// Return appropriate font for different scripts
return switch (locale.languageCode) {
'ar' || 'fa' || 'ur' => 'Noto Sans Arabic',
'he' => 'Noto Sans Hebrew',
'zh' => 'Noto Sans SC',
'ja' => 'Noto Sans JP',
'ko' => 'Noto Sans KR',
'hi' || 'mr' => 'Noto Sans Devanagari',
'th' => 'Noto Sans Thai',
_ => null, // Use default
};
}
double _getBaseFontSizeForLocale(Locale locale) {
// Complex scripts may need larger base sizes
return switch (locale.languageCode) {
'zh' || 'ja' || 'ko' => 18,
'ar' || 'fa' || 'he' => 17,
'th' => 17,
_ => 16,
};
}
double _getLineHeightForLocale(Locale locale) {
// Adjust line height for scripts with diacritics
return switch (locale.languageCode) {
'ar' || 'fa' || 'ur' => 1.6,
'th' => 1.5,
'hi' || 'mr' => 1.5,
_ => 1.4,
};
}
}
ARB File Structure for AnimatedDefaultTextStyle
{
"highlightedTitleAccessibility": "Highlighted: {title}",
"@highlightedTitleAccessibility": {
"description": "Accessibility label for highlighted title",
"placeholders": {
"title": {"type": "String"}
}
},
"sectionTitle": "Features",
"@sectionTitle": {
"description": "Section title"
},
"readMore": "Read more",
"@readMore": {
"description": "Read more link text"
},
"readLess": "Read less",
"@readLess": {
"description": "Read less link text"
}
}
Selectable Text with Style Animation
Create selectable text items with animated styling:
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
class LocalizedSelectableTextList extends StatefulWidget {
const LocalizedSelectableTextList({super.key});
@override
State<LocalizedSelectableTextList> createState() =>
_LocalizedSelectableTextListState();
}
class _LocalizedSelectableTextListState
extends State<LocalizedSelectableTextList> {
int _selectedIndex = 0;
@override
Widget build(BuildContext context) {
final l10n = AppLocalizations.of(context)!;
final options = [
_TextOption(l10n.optionSmall, l10n.optionSmallDescription),
_TextOption(l10n.optionMedium, l10n.optionMediumDescription),
_TextOption(l10n.optionLarge, l10n.optionLargeDescription),
_TextOption(l10n.optionExtraLarge, l10n.optionExtraLargeDescription),
];
return Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Padding(
padding: const EdgeInsets.all(16),
child: Text(
l10n.selectSizeLabel,
style: Theme.of(context).textTheme.titleMedium,
),
),
...options.asMap().entries.map((entry) {
final index = entry.key;
final option = entry.value;
final isSelected = index == _selectedIndex;
return _LocalizedSelectableTextItem(
title: option.title,
description: option.description,
isSelected: isSelected,
onTap: () => setState(() => _selectedIndex = index),
selectedAccessibility: l10n.optionSelected(option.title),
unselectedAccessibility: l10n.optionUnselected(option.title),
);
}),
],
);
}
}
class _TextOption {
final String title;
final String description;
_TextOption(this.title, this.description);
}
class _LocalizedSelectableTextItem extends StatelessWidget {
final String title;
final String description;
final bool isSelected;
final VoidCallback onTap;
final String selectedAccessibility;
final String unselectedAccessibility;
const _LocalizedSelectableTextItem({
required this.title,
required this.description,
required this.isSelected,
required this.onTap,
required this.selectedAccessibility,
required this.unselectedAccessibility,
});
@override
Widget build(BuildContext context) {
final isRtl = Directionality.of(context) == TextDirection.rtl;
return Semantics(
selected: isSelected,
label: isSelected ? selectedAccessibility : unselectedAccessibility,
child: GestureDetector(
onTap: onTap,
child: AnimatedContainer(
duration: const Duration(milliseconds: 250),
margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
padding: const EdgeInsets.all(16),
decoration: BoxDecoration(
color: isSelected
? Theme.of(context).colorScheme.primaryContainer
: Theme.of(context).colorScheme.surface,
borderRadius: BorderRadius.circular(12),
border: Border.all(
color: isSelected
? Theme.of(context).colorScheme.primary
: Theme.of(context).colorScheme.outline.withOpacity(0.2),
width: isSelected ? 2 : 1,
),
),
child: Row(
children: [
// Radio indicator
AnimatedContainer(
duration: const Duration(milliseconds: 200),
width: 24,
height: 24,
decoration: BoxDecoration(
shape: BoxShape.circle,
border: Border.all(
color: isSelected
? Theme.of(context).colorScheme.primary
: Theme.of(context).colorScheme.outline,
width: 2,
),
),
child: Center(
child: AnimatedContainer(
duration: const Duration(milliseconds: 200),
width: isSelected ? 12 : 0,
height: isSelected ? 12 : 0,
decoration: BoxDecoration(
shape: BoxShape.circle,
color: Theme.of(context).colorScheme.primary,
),
),
),
),
const SizedBox(width: 16),
// Text content
Expanded(
child: Column(
crossAxisAlignment: isRtl
? CrossAxisAlignment.end
: CrossAxisAlignment.start,
children: [
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 250),
style: Theme.of(context).textTheme.titleMedium!.copyWith(
fontWeight:
isSelected ? FontWeight.bold : FontWeight.normal,
color: isSelected
? Theme.of(context).colorScheme.onPrimaryContainer
: Theme.of(context).colorScheme.onSurface,
),
child: Text(title),
),
const SizedBox(height: 4),
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 250),
style: Theme.of(context).textTheme.bodySmall!.copyWith(
color: isSelected
? Theme.of(context)
.colorScheme
.onPrimaryContainer
.withOpacity(0.8)
: Theme.of(context)
.colorScheme
.onSurface
.withOpacity(0.6),
),
child: Text(description),
),
],
),
),
// Checkmark
AnimatedOpacity(
duration: const Duration(milliseconds: 200),
opacity: isSelected ? 1 : 0,
child: Icon(
Icons.check_circle,
color: Theme.of(context).colorScheme.primary,
),
),
],
),
),
),
);
}
}
Theme Transition with Text Style Animation
Create a theme toggle with animated text styles:
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
class LocalizedThemeTextDemo extends StatefulWidget {
const LocalizedThemeTextDemo({super.key});
@override
State<LocalizedThemeTextDemo> createState() => _LocalizedThemeTextDemoState();
}
class _LocalizedThemeTextDemoState extends State<LocalizedThemeTextDemo> {
bool _isDarkMode = false;
@override
Widget build(BuildContext context) {
final l10n = AppLocalizations.of(context)!;
final isRtl = Directionality.of(context) == TextDirection.rtl;
// Define theme-specific styles
final titleStyle = _isDarkMode
? const TextStyle(
fontSize: 28,
fontWeight: FontWeight.bold,
color: Colors.white,
letterSpacing: 1.0,
)
: TextStyle(
fontSize: 28,
fontWeight: FontWeight.bold,
color: Colors.grey.shade900,
letterSpacing: 0.5,
);
final bodyStyle = _isDarkMode
? TextStyle(
fontSize: 16,
color: Colors.grey.shade300,
height: 1.6,
)
: TextStyle(
fontSize: 16,
color: Colors.grey.shade700,
height: 1.5,
);
final captionStyle = _isDarkMode
? TextStyle(
fontSize: 12,
color: Colors.grey.shade500,
fontStyle: FontStyle.italic,
)
: TextStyle(
fontSize: 12,
color: Colors.grey.shade600,
fontStyle: FontStyle.normal,
);
return AnimatedContainer(
duration: const Duration(milliseconds: 400),
padding: const EdgeInsets.all(24),
decoration: BoxDecoration(
color: _isDarkMode ? const Color(0xFF1A1A2E) : Colors.white,
borderRadius: BorderRadius.circular(16),
),
child: Column(
crossAxisAlignment:
isRtl ? CrossAxisAlignment.end : CrossAxisAlignment.start,
children: [
// Theme toggle
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 300),
style: bodyStyle,
child: Text(l10n.themeLabel),
),
Semantics(
label: _isDarkMode
? l10n.switchToLightMode
: l10n.switchToDarkMode,
child: Switch(
value: _isDarkMode,
onChanged: (value) => setState(() => _isDarkMode = value),
),
),
],
),
const SizedBox(height: 24),
// Animated title
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 400),
style: titleStyle,
child: Text(l10n.sampleTitle),
),
const SizedBox(height: 16),
// Animated body
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 400),
style: bodyStyle,
child: Text(l10n.sampleBody),
),
const SizedBox(height: 12),
// Animated caption
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 400),
style: captionStyle,
child: Text(l10n.sampleCaption),
),
],
),
);
}
}
Text Size Accessibility Controls
Create text size controls with animated transitions:
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
class LocalizedTextSizeControls extends StatefulWidget {
const LocalizedTextSizeControls({super.key});
@override
State<LocalizedTextSizeControls> createState() =>
_LocalizedTextSizeControlsState();
}
class _LocalizedTextSizeControlsState extends State<LocalizedTextSizeControls> {
double _textScale = 1.0;
static const double _minScale = 0.8;
static const double _maxScale = 1.5;
@override
Widget build(BuildContext context) {
final l10n = AppLocalizations.of(context)!;
final isRtl = Directionality.of(context) == TextDirection.rtl;
final baseStyle = Theme.of(context).textTheme.bodyLarge!;
return Column(
crossAxisAlignment:
isRtl ? CrossAxisAlignment.end : CrossAxisAlignment.start,
children: [
// Size controls
Container(
padding: const EdgeInsets.all(16),
decoration: BoxDecoration(
color: Theme.of(context).colorScheme.surfaceVariant,
borderRadius: BorderRadius.circular(12),
),
child: Column(
children: [
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text(
l10n.textSizeLabel,
style: Theme.of(context).textTheme.titleSmall,
),
Text(
l10n.textSizePercent((_textScale * 100).round()),
style: Theme.of(context).textTheme.labelLarge?.copyWith(
color: Theme.of(context).colorScheme.primary,
fontWeight: FontWeight.bold,
),
),
],
),
const SizedBox(height: 8),
Row(
children: [
IconButton(
onPressed: _textScale > _minScale
? () => setState(() {
_textScale = (_textScale - 0.1).clamp(
_minScale,
_maxScale,
);
})
: null,
icon: const Icon(Icons.text_decrease),
tooltip: l10n.decreaseTextSize,
),
Expanded(
child: Semantics(
label: l10n.textSizeSliderAccessibility(
(_textScale * 100).round(),
),
child: Slider(
value: _textScale,
min: _minScale,
max: _maxScale,
divisions: 7,
onChanged: (value) => setState(() => _textScale = value),
),
),
),
IconButton(
onPressed: _textScale < _maxScale
? () => setState(() {
_textScale = (_textScale + 0.1).clamp(
_minScale,
_maxScale,
);
})
: null,
icon: const Icon(Icons.text_increase),
tooltip: l10n.increaseTextSize,
),
],
),
// Quick select buttons
const SizedBox(height: 8),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
_QuickScaleButton(
label: l10n.sizeSmall,
scale: 0.85,
currentScale: _textScale,
onTap: () => setState(() => _textScale = 0.85),
),
_QuickScaleButton(
label: l10n.sizeNormal,
scale: 1.0,
currentScale: _textScale,
onTap: () => setState(() => _textScale = 1.0),
),
_QuickScaleButton(
label: l10n.sizeLarge,
scale: 1.2,
currentScale: _textScale,
onTap: () => setState(() => _textScale = 1.2),
),
_QuickScaleButton(
label: l10n.sizeExtraLarge,
scale: 1.4,
currentScale: _textScale,
onTap: () => setState(() => _textScale = 1.4),
),
],
),
],
),
),
const SizedBox(height: 24),
// Preview text
Container(
padding: const EdgeInsets.all(16),
decoration: BoxDecoration(
border: Border.all(
color: Theme.of(context).colorScheme.outline.withOpacity(0.3),
),
borderRadius: BorderRadius.circular(12),
),
child: Column(
crossAxisAlignment:
isRtl ? CrossAxisAlignment.end : CrossAxisAlignment.start,
children: [
Text(
l10n.previewLabel,
style: Theme.of(context).textTheme.labelMedium?.copyWith(
color: Theme.of(context).colorScheme.outline,
),
),
const SizedBox(height: 12),
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 200),
style: baseStyle.copyWith(
fontSize: baseStyle.fontSize! * _textScale,
height: 1.5,
),
child: Text(l10n.previewText),
),
],
),
),
],
);
}
}
class _QuickScaleButton extends StatelessWidget {
final String label;
final double scale;
final double currentScale;
final VoidCallback onTap;
const _QuickScaleButton({
required this.label,
required this.scale,
required this.currentScale,
required this.onTap,
});
@override
Widget build(BuildContext context) {
final isSelected = (currentScale - scale).abs() < 0.05;
return GestureDetector(
onTap: onTap,
child: AnimatedContainer(
duration: const Duration(milliseconds: 200),
padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
decoration: BoxDecoration(
color: isSelected
? Theme.of(context).colorScheme.primary
: Colors.transparent,
borderRadius: BorderRadius.circular(16),
border: Border.all(
color: isSelected
? Theme.of(context).colorScheme.primary
: Theme.of(context).colorScheme.outline.withOpacity(0.5),
),
),
child: AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 200),
style: Theme.of(context).textTheme.labelMedium!.copyWith(
color: isSelected
? Theme.of(context).colorScheme.onPrimary
: Theme.of(context).colorScheme.onSurface,
fontWeight: isSelected ? FontWeight.bold : FontWeight.normal,
),
child: Text(label),
),
),
);
}
}
Form Validation with Animated Error Styles
Create form fields with animated error text styles:
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
class LocalizedAnimatedFormField extends StatefulWidget {
final String label;
final String hint;
final String? Function(String?) validator;
final TextEditingController? controller;
final bool obscureText;
const LocalizedAnimatedFormField({
super.key,
required this.label,
required this.hint,
required this.validator,
this.controller,
this.obscureText = false,
});
@override
State<LocalizedAnimatedFormField> createState() =>
_LocalizedAnimatedFormFieldState();
}
class _LocalizedAnimatedFormFieldState
extends State<LocalizedAnimatedFormField> {
String? _errorMessage;
bool _isFocused = false;
bool _hasInteracted = false;
final FocusNode _focusNode = FocusNode();
late TextEditingController _controller;
@override
void initState() {
super.initState();
_controller = widget.controller ?? TextEditingController();
_focusNode.addListener(_handleFocusChange);
_controller.addListener(_validateOnChange);
}
void _handleFocusChange() {
setState(() {
_isFocused = _focusNode.hasFocus;
if (!_focusNode.hasFocus && _hasInteracted) {
_validate();
}
});
}
void _validateOnChange() {
if (_hasInteracted) {
_validate();
}
}
void _validate() {
setState(() {
_hasInteracted = true;
_errorMessage = widget.validator(_controller.text);
});
}
@override
void dispose() {
_focusNode.removeListener(_handleFocusChange);
_focusNode.dispose();
if (widget.controller == null) {
_controller.dispose();
}
super.dispose();
}
@override
Widget build(BuildContext context) {
final l10n = AppLocalizations.of(context)!;
final isRtl = Directionality.of(context) == TextDirection.rtl;
final hasError = _errorMessage != null;
return Column(
crossAxisAlignment:
isRtl ? CrossAxisAlignment.end : CrossAxisAlignment.start,
children: [
// Label
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 200),
style: Theme.of(context).textTheme.labelLarge!.copyWith(
color: hasError
? Theme.of(context).colorScheme.error
: _isFocused
? Theme.of(context).colorScheme.primary
: Theme.of(context).colorScheme.onSurface,
fontWeight: _isFocused ? FontWeight.bold : FontWeight.normal,
),
child: Text(widget.label),
),
const SizedBox(height: 8),
// Input field
AnimatedContainer(
duration: const Duration(milliseconds: 200),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(_isFocused ? 12 : 8),
border: Border.all(
color: hasError
? Theme.of(context).colorScheme.error
: _isFocused
? Theme.of(context).colorScheme.primary
: Theme.of(context).colorScheme.outline.withOpacity(0.3),
width: _isFocused || hasError ? 2 : 1,
),
boxShadow: _isFocused
? [
BoxShadow(
color: (hasError
? Theme.of(context).colorScheme.error
: Theme.of(context).colorScheme.primary)
.withOpacity(0.1),
blurRadius: 8,
offset: const Offset(0, 2),
),
]
: null,
),
child: TextField(
controller: _controller,
focusNode: _focusNode,
obscureText: widget.obscureText,
textDirection: isRtl ? TextDirection.rtl : TextDirection.ltr,
decoration: InputDecoration(
hintText: widget.hint,
border: InputBorder.none,
contentPadding: const EdgeInsets.symmetric(
horizontal: 16,
vertical: 12,
),
suffixIcon: hasError
? Icon(
Icons.error_outline,
color: Theme.of(context).colorScheme.error,
)
: null,
),
onTap: () => setState(() => _hasInteracted = true),
),
),
// Error message
AnimatedSize(
duration: const Duration(milliseconds: 200),
child: AnimatedOpacity(
duration: const Duration(milliseconds: 200),
opacity: hasError ? 1 : 0,
child: hasError
? Padding(
padding: const EdgeInsets.only(top: 8),
child: Row(
children: [
Icon(
Icons.info_outline,
size: 16,
color: Theme.of(context).colorScheme.error,
),
const SizedBox(width: 4),
Expanded(
child: AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 200),
style:
Theme.of(context).textTheme.bodySmall!.copyWith(
color: Theme.of(context).colorScheme.error,
),
child: Text(_errorMessage ?? ''),
),
),
],
),
)
: const SizedBox.shrink(),
),
),
],
);
}
}
Tab Labels with Animated Text Style
Create animated tab labels:
import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
class LocalizedAnimatedTabs extends StatefulWidget {
const LocalizedAnimatedTabs({super.key});
@override
State<LocalizedAnimatedTabs> createState() => _LocalizedAnimatedTabsState();
}
class _LocalizedAnimatedTabsState extends State<LocalizedAnimatedTabs> {
int _selectedIndex = 0;
@override
Widget build(BuildContext context) {
final l10n = AppLocalizations.of(context)!;
final isRtl = Directionality.of(context) == TextDirection.rtl;
final tabs = [
_TabData(l10n.tabOverview, Icons.dashboard),
_TabData(l10n.tabDetails, Icons.list_alt),
_TabData(l10n.tabReviews, Icons.rate_review),
_TabData(l10n.tabRelated, Icons.apps),
];
return Column(
children: [
// Tab bar
Container(
height: 56,
decoration: BoxDecoration(
color: Theme.of(context).colorScheme.surfaceVariant,
borderRadius: BorderRadius.circular(12),
),
child: Row(
textDirection: isRtl ? TextDirection.rtl : TextDirection.ltr,
children: tabs.asMap().entries.map((entry) {
final index = entry.key;
final tab = entry.value;
final isSelected = index == _selectedIndex;
return Expanded(
child: Semantics(
selected: isSelected,
label: l10n.tabAccessibilityLabel(
tab.label,
index + 1,
tabs.length,
),
child: GestureDetector(
onTap: () => setState(() => _selectedIndex = index),
behavior: HitTestBehavior.opaque,
child: AnimatedContainer(
duration: const Duration(milliseconds: 200),
margin: const EdgeInsets.all(4),
decoration: BoxDecoration(
color: isSelected
? Theme.of(context).colorScheme.surface
: Colors.transparent,
borderRadius: BorderRadius.circular(8),
boxShadow: isSelected
? [
BoxShadow(
color: Colors.black.withOpacity(0.05),
blurRadius: 4,
offset: const Offset(0, 2),
),
]
: null,
),
child: Center(
child: Row(
mainAxisSize: MainAxisSize.min,
children: [
AnimatedContainer(
duration: const Duration(milliseconds: 200),
child: Icon(
tab.icon,
size: isSelected ? 20 : 18,
color: isSelected
? Theme.of(context).colorScheme.primary
: Theme.of(context)
.colorScheme
.onSurfaceVariant,
),
),
const SizedBox(width: 6),
AnimatedDefaultTextStyle(
duration: const Duration(milliseconds: 200),
style: Theme.of(context)
.textTheme
.labelMedium!
.copyWith(
fontSize: isSelected ? 14 : 13,
fontWeight: isSelected
? FontWeight.bold
: FontWeight.normal,
color: isSelected
? Theme.of(context).colorScheme.primary
: Theme.of(context)
.colorScheme
.onSurfaceVariant,
),
child: Text(tab.label),
),
],
),
),
),
),
),
);
}).toList(),
),
),
const SizedBox(height: 16),
// Tab content
AnimatedSwitcher(
duration: const Duration(milliseconds: 200),
child: Container(
key: ValueKey(_selectedIndex),
padding: const EdgeInsets.all(24),
decoration: BoxDecoration(
color: Theme.of(context).colorScheme.surface,
borderRadius: BorderRadius.circular(12),
border: Border.all(
color: Theme.of(context).colorScheme.outline.withOpacity(0.1),
),
),
child: Center(
child: Text(
l10n.tabContentPlaceholder(tabs[_selectedIndex].label),
style: Theme.of(context).textTheme.bodyLarge,
),
),
),
),
],
);
}
}
class _TabData {
final String label;
final IconData icon;
_TabData(this.label, this.icon);
}
Complete ARB File for AnimatedDefaultTextStyle
{
"@@locale": "en",
"highlightedTitleAccessibility": "Highlighted: {title}",
"@highlightedTitleAccessibility": {
"placeholders": {
"title": {"type": "String"}
}
},
"selectSizeLabel": "Select a size option:",
"optionSmall": "Small",
"optionSmallDescription": "Compact size for minimal footprint",
"optionMedium": "Medium",
"optionMediumDescription": "Balanced size for everyday use",
"optionLarge": "Large",
"optionLargeDescription": "Generous size for comfort",
"optionExtraLarge": "Extra Large",
"optionExtraLargeDescription": "Maximum size for best visibility",
"optionSelected": "{option} selected",
"@optionSelected": {
"placeholders": {
"option": {"type": "String"}
}
},
"optionUnselected": "{option}, tap to select",
"@optionUnselected": {
"placeholders": {
"option": {"type": "String"}
}
},
"themeLabel": "Dark mode",
"switchToLightMode": "Switch to light mode",
"switchToDarkMode": "Switch to dark mode",
"sampleTitle": "Welcome to Our App",
"sampleBody": "This is a sample paragraph demonstrating how text styles animate smoothly between different themes. Notice how the colors, weights, and spacing transition gracefully.",
"sampleCaption": "Last updated: Today",
"textSizeLabel": "Text Size",
"textSizePercent": "{percent}%",
"@textSizePercent": {
"placeholders": {
"percent": {"type": "int"}
}
},
"decreaseTextSize": "Decrease text size",
"increaseTextSize": "Increase text size",
"textSizeSliderAccessibility": "Text size at {percent} percent",
"@textSizeSliderAccessibility": {
"placeholders": {
"percent": {"type": "int"}
}
},
"sizeSmall": "Small",
"sizeNormal": "Normal",
"sizeLarge": "Large",
"sizeExtraLarge": "XL",
"previewLabel": "Preview",
"previewText": "The quick brown fox jumps over the lazy dog. This sentence contains every letter of the alphabet and is perfect for previewing text styles.",
"tabOverview": "Overview",
"tabDetails": "Details",
"tabReviews": "Reviews",
"tabRelated": "Related",
"tabAccessibilityLabel": "{label}, tab {current} of {total}",
"@tabAccessibilityLabel": {
"placeholders": {
"label": {"type": "String"},
"current": {"type": "int"},
"total": {"type": "int"}
}
},
"tabContentPlaceholder": "{tab} content goes here",
"@tabContentPlaceholder": {
"placeholders": {
"tab": {"type": "String"}
}
}
}
Best Practices Summary
- Use locale-appropriate fonts: Load fonts that support the target script (Arabic, CJK, Devanagari)
- Adjust line heights: Scripts with diacritics need more vertical space
- Support text scaling: Always test with system text size multipliers
- Animate purposefully: Use text style changes to indicate state transitions
- Consider script complexity: Some scripts need larger base font sizes
- Handle RTL alignment: Use TextAlign.start/end instead of left/right
- Provide accessibility labels: Announce significant style changes
- Test with real translations: Some languages have much longer text
- Use semantic colors: Error, warning, success states should use appropriate colors
- Respect system settings: Honor platform accessibility preferences
Conclusion
Proper AnimatedDefaultTextStyle localization ensures smooth, accessible typography transitions across all languages and scripts. By handling locale-specific fonts, adjusting for text expansion, and providing comprehensive accessibility support, you create polished text animations that feel native to users worldwide. The patterns shown here—selectable lists, theme transitions, text size controls, and form validation—can be adapted to any Flutter application requiring animated text styling.
Remember to test your text style animations with different locales to verify that fonts, sizing, and accessibility work correctly for all your supported languages and scripts.