pipe_x 1.4.0 
pipe_x: ^1.4.0 copied to clipboard
navaneethk.devA lightweight, reactive state management library for Flutter with fine-grained reactivity and minimal boilerplate.
example/lib/main.dart
import 'package:flutter/material.dart';
import 'package:pipe_x/pipe_x.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'PipeX State Management Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.green),
useMaterial3: true,
),
initialRoute: '/',
onGenerateRoute: _onGenerateRoute,
);
}
static Route<dynamic>? _onGenerateRoute(RouteSettings settings) {
switch (settings.name) {
case '/':
return MaterialPageRoute(builder: (_) => const ExamplesListScreen());
case '/counter':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => CounterHub(),
child: const CounterExample(),
),
);
case '/multiple-pipes':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => UserHub(),
child: const MultiplePipesExample(),
),
);
case '/standalone-pipe':
return MaterialPageRoute(builder: (_) => const StandalonePipeExample());
case '/single-sink':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => TimerHub()..startTimer(),
child: const SingleSinkExample(),
),
);
case '/multiple-sinks':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => MultiCounterHub(),
child: const MultipleSinksExample(),
),
);
case '/well':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => CalculatorHub(),
child: const WellExample(),
),
);
case '/hub-provider':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => ThemeHub(),
child: const HubProviderExample(),
),
);
case '/multi-hub-provider':
return MaterialPageRoute(
builder: (_) => MultiHubProvider(
hubs: [
() => AuthHub(),
() => SettingsHub(),
],
child: const MultiHubProviderExample(),
),
);
case '/hub-provider-value':
// Pre-create the hub instance
final preCreatedHub = ThemeHub();
return MaterialPageRoute(
builder: (_) => HubProvider<ThemeHub>.value(
value: preCreatedHub,
child: const HubProviderValueExample(),
),
);
case '/multi-hub-provider-value':
// Pre-create hub instances
final authHub = AuthHub();
final settingsHub = SettingsHub();
return MaterialPageRoute(
builder: (_) => MultiHubProvider(
hubs: [
authHub, // Existing instance
settingsHub, // Existing instance
],
child: const MultiHubProviderValueExample(),
),
);
case '/scoped-vs-global':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => CounterGlobalHub(),
child: const ScopedVsGlobalExample(),
),
);
case '/computed-values':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => ShoppingHub(),
child: const ComputedValuesExample(),
),
);
case '/async':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => DataHub(),
child: const AsyncExample(),
),
);
case '/form':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => FormHub(),
child: const FormExample(),
),
);
case '/class-type':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => UserProfileHub(),
child: const ClassTypeExample(),
),
);
case '/hub-listener':
return MaterialPageRoute(
builder: (_) => HubProvider(
create: () => TargetCounterHub(),
child: const HubListenerExample(),
),
);
default:
return null;
}
}
}
class ExamplesListScreen extends StatelessWidget {
const ExamplesListScreen({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('💧 PipeX Examples'),
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
),
body: ListView(
children: [
_buildSection(context, '📦 Basic Examples', const [
_Example('Counter with Hub', '/counter'),
_Example('Multiple Pipes', '/multiple-pipes'),
_Example('Standalone Pipe (Auto-dispose)', '/standalone-pipe'),
_Example('Class Type in Pipe', '/class-type'),
]),
_buildSection(context, '🔄 Reactive Widgets', const [
_Example('Single Sink', '/single-sink'),
_Example('Multiple Sinks', '/multiple-sinks'),
_Example('Well (Multiple Pipes)', '/well'),
]),
_buildSection(context, '🏗️ Dependency Injection', const [
_Example('HubProvider Basics', '/hub-provider'),
_Example('MultiHubProvider', '/multi-hub-provider'),
_Example('HubProvider.value (External Lifecycle)',
'/hub-provider-value'),
_Example(
'MultiHubProvider with Values', '/multi-hub-provider-value'),
_Example('Scoped vs Global', '/scoped-vs-global'),
]),
_buildSection(context, '⚡ Advanced Patterns', const [
_Example('Computed Values (Getters)', '/computed-values'),
_Example('Async Operations', '/async'),
_Example('Form Management', '/form'),
_Example('HubListener (Conditional Side Effects)', '/hub-listener'),
]),
],
),
);
}
Widget _buildSection(
BuildContext context, String title, List<_Example> examples) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Padding(
padding: const EdgeInsets.fromLTRB(16, 24, 16, 8),
child: Text(
title,
style: Theme.of(context).textTheme.titleLarge?.copyWith(
fontWeight: FontWeight.bold,
),
),
),
...examples.map((example) => ListTile(
leading: const Icon(Icons.arrow_forward_ios, size: 16),
title: Text(example.title),
onTap: () => Navigator.pushNamed(context, example.route),
)),
const Divider(),
],
);
}
}
class _Example {
final String title;
final String route;
const _Example(this.title, this.route);
}
// ============================================================================
// EXAMPLE 1: Counter with Hub
// ============================================================================
class CounterHub extends Hub {
late final count = pipe(0);
void increment() => count.value++;
void decrement() => count.value--;
void reset() => count.value = 0;
}
class CounterExample extends StatelessWidget {
const CounterExample({super.key});
@override
Widget build(BuildContext context) {
final hub = context.read<CounterHub>();
return Scaffold(
appBar: AppBar(title: const Text('Counter Example')),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text('Basic counter with Hub & Sink:'),
const SizedBox(height: 16),
Sink(
pipe: hub.count,
builder: (context, value) {
return Text(
'$value',
style: Theme.of(context).textTheme.displayLarge,
);
},
),
const SizedBox(height: 24),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
FloatingActionButton(
heroTag: 'dec',
onPressed: () => hub.decrement(),
child: const Icon(Icons.remove),
),
const SizedBox(width: 16),
FloatingActionButton(
heroTag: 'inc',
onPressed: () => hub.increment(),
child: const Icon(Icons.add),
),
],
),
const SizedBox(height: 16),
ElevatedButton(
onPressed: () => hub.reset(),
child: const Text('Reset'),
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 2: Multiple Pipes
// ============================================================================
class UserHub extends Hub {
late final name = pipe('John Doe');
late final age = pipe(25);
late final email = pipe('john@example.com');
// Computed value using getter
String get summary => '${name.value}, ${age.value} years old';
}
class MultiplePipesExample extends StatelessWidget {
const MultiplePipesExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Multiple Pipes')),
body: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Text('Multiple independent pipes in one Hub:'),
const SizedBox(height: 24),
Sink(
pipe: context.read<UserHub>().name,
builder: (context, value) =>
Text('Name: $value', style: const TextStyle(fontSize: 18)),
),
const SizedBox(height: 8),
Sink(
pipe: context.read<UserHub>().age,
builder: (context, value) =>
Text('Age: $value', style: const TextStyle(fontSize: 18)),
),
const SizedBox(height: 8),
Sink(
pipe: context.read<UserHub>().email,
builder: (context, value) =>
Text('Email: $value', style: const TextStyle(fontSize: 18)),
),
const SizedBox(height: 24),
ElevatedButton(
onPressed: () {
final hub = context.read<UserHub>();
hub.name.value = 'Jane Smith';
hub.age.value = 30;
hub.email.value = 'jane@example.com';
},
child: const Text('Update User'),
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 3: Standalone Pipe (Auto-dispose)
// ============================================================================
class StandalonePipeExample extends StatefulWidget {
const StandalonePipeExample({super.key});
@override
State<StandalonePipeExample> createState() => _StandalonePipeExampleState();
}
class _StandalonePipeExampleState extends State<StandalonePipeExample> {
late final Pipe<int> counter;
late final Pipe<String> message;
@override
void initState() {
super.initState();
// These pipes are created outside a Hub, so they'll auto-dispose
counter = Pipe(0);
message = Pipe('Hello!');
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Standalone Pipe')),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text('Pipes without Hub (auto-dispose on unmount):'),
const SizedBox(height: 24),
Sink(
pipe: counter,
builder: (context, value) => Text(
'Counter: $value',
style: const TextStyle(fontSize: 24),
),
),
const SizedBox(height: 16),
Sink(
pipe: message,
builder: (context, value) => Text(
value,
style: const TextStyle(fontSize: 18, color: Colors.blue),
),
),
const SizedBox(height: 24),
ElevatedButton(
onPressed: () {
counter.value++;
message.value = 'Count: ${counter.value}';
},
child: const Text('Increment'),
),
const SizedBox(height: 16),
Text(
'These pipes will auto-dispose when you go back',
style: TextStyle(fontSize: 12, color: Colors.grey[600]),
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 4: Single Sink
// ============================================================================
class TimerHub extends Hub {
late final seconds = pipe(0);
void startTimer() {
Future.doWhile(() async {
await Future.delayed(const Duration(seconds: 1));
if (!disposed) {
seconds.value++;
return true;
}
return false;
});
}
}
class SingleSinkExample extends StatelessWidget {
const SingleSinkExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Single Sink')),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text('Only the Sink rebuilds, not the entire screen:'),
const SizedBox(height: 24),
Container(
padding: const EdgeInsets.all(24),
decoration: BoxDecoration(
color: Colors.blue[50],
borderRadius: BorderRadius.circular(12),
),
child: Sink(
pipe: context.read<TimerHub>().seconds,
builder: (context, value) {
return Text(
'Timer: $value seconds',
style: const TextStyle(
fontSize: 32, fontWeight: FontWeight.bold),
);
},
),
),
const SizedBox(height: 24),
const Text(
'This text never rebuilds!',
style: TextStyle(fontSize: 16, color: Colors.grey),
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 5: Multiple Sinks
// ============================================================================
class MultiCounterHub extends Hub {
late final counterA = pipe(0);
late final counterB = pipe(0);
late final counterC = pipe(0);
void incrementA() => counterA.value++;
void incrementB() => counterB.value++;
void incrementC() => counterC.value++;
}
class MultipleSinksExample extends StatelessWidget {
const MultipleSinksExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Multiple Sinks')),
body: Padding(
padding: const EdgeInsets.all(16),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text('Each Sink rebuilds independently:'),
const SizedBox(height: 32),
_CounterRow('Counter A', context.read<MultiCounterHub>().counterA,
() {
context.read<MultiCounterHub>().incrementA();
}),
const SizedBox(height: 16),
_CounterRow('Counter B', context.read<MultiCounterHub>().counterB,
() {
context.read<MultiCounterHub>().incrementB();
}),
const SizedBox(height: 16),
_CounterRow('Counter C', context.read<MultiCounterHub>().counterC,
() {
context.read<MultiCounterHub>().incrementC();
}),
],
),
),
);
}
}
class _CounterRow extends StatelessWidget {
final String label;
final Pipe<int> pipe;
final VoidCallback onIncrement;
const _CounterRow(this.label, this.pipe, this.onIncrement);
@override
Widget build(BuildContext context) {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text(label, style: const TextStyle(fontSize: 18)),
Row(
children: [
Sink(
pipe: pipe,
builder: (context, value) => Container(
padding:
const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
decoration: BoxDecoration(
color: Colors.green[100],
borderRadius: BorderRadius.circular(8),
),
child: Text('$value',
style: const TextStyle(
fontSize: 20, fontWeight: FontWeight.bold)),
),
),
const SizedBox(width: 8),
IconButton(
icon: const Icon(Icons.add),
onPressed: onIncrement,
),
],
),
],
);
}
}
// ============================================================================
// EXAMPLE 6: Well (Multiple Pipes)
// ============================================================================
class CalculatorHub extends Hub {
late final a = pipe(5);
late final b = pipe(10);
late final operation = pipe<String>('+');
double get result {
switch (operation.value) {
case '+':
return (a.value + b.value).toDouble();
case '-':
return (a.value - b.value).toDouble();
case '*':
return (a.value * b.value).toDouble();
case '/':
return b.value != 0 ? a.value / b.value : 0;
default:
return 0;
}
}
}
class WellExample extends StatelessWidget {
const WellExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Well Example')),
body: Padding(
padding: const EdgeInsets.all(16),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text('Well listens to multiple pipes at once:'),
const SizedBox(height: 32),
Well(
pipes: [
context.read<CalculatorHub>().a,
context.read<CalculatorHub>().b,
context.read<CalculatorHub>().operation,
],
builder: (context) {
final hub = context.read<CalculatorHub>();
return Container(
padding: const EdgeInsets.all(24),
decoration: BoxDecoration(
color: Colors.purple[50],
borderRadius: BorderRadius.circular(12),
),
child: Column(
children: [
Text(
'${hub.a.value} ${hub.operation.value} ${hub.b.value} = ${hub.result.toStringAsFixed(2)}',
style: const TextStyle(
fontSize: 24, fontWeight: FontWeight.bold),
),
],
),
);
},
),
const SizedBox(height: 32),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
ElevatedButton(
onPressed: () => context.read<CalculatorHub>().a.value++,
child: const Text('A+'),
),
ElevatedButton(
onPressed: () => context.read<CalculatorHub>().b.value++,
child: const Text('B+'),
),
],
),
const SizedBox(height: 16),
Wrap(
spacing: 8,
children: ['+', '-', '*', '/'].map((op) {
return ElevatedButton(
onPressed: () =>
context.read<CalculatorHub>().operation.value = op,
child: Text(op),
);
}).toList(),
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 7: HubProvider Basics
// ============================================================================
class ThemeHub extends Hub {
late final isDark = pipe(false);
void toggle() => isDark.value = !isDark.value;
}
class HubProviderExample extends StatelessWidget {
const HubProviderExample({super.key});
@override
Widget build(BuildContext context) {
return Sink(
pipe: context.read<ThemeHub>().isDark,
builder: (context, isDark) {
return MaterialApp(
theme: isDark ? ThemeData.dark() : ThemeData.light(),
home: Scaffold(
appBar: AppBar(
title: const Text('HubProvider Example'),
leading: IconButton(
icon: const Icon(Icons.arrow_back),
onPressed: () => Navigator.of(context).pop(),
),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
isDark ? '🌙 Dark Mode' : '☀️ Light Mode',
style: const TextStyle(fontSize: 32),
),
const SizedBox(height: 24),
ElevatedButton(
onPressed: () => context.read<ThemeHub>().toggle(),
child: const Text('Toggle Theme'),
),
],
),
),
),
);
},
);
}
}
// ============================================================================
// EXAMPLE 8: MultiHubProvider
// ============================================================================
class AuthHub extends Hub {
late final isLoggedIn = pipe(false);
late final username = pipe('Guest');
void login(String name) {
username.value = name;
isLoggedIn.value = true;
}
void logout() {
username.value = 'Guest';
isLoggedIn.value = false;
}
}
class SettingsHub extends Hub {
late final fontSize = pipe(16.0);
late final enableNotifications = pipe(true);
void increaseFontSize() => fontSize.value += 2;
void decreaseFontSize() => fontSize.value -= 2;
}
class MultiHubProviderExample extends StatelessWidget {
const MultiHubProviderExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('MultiHubProvider')),
body: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Text('Multiple Hubs without nesting:',
style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
const SizedBox(height: 24),
Well(
pipes: [
context.read<AuthHub>().isLoggedIn,
context.read<AuthHub>().username,
],
builder: (context) {
final auth = context.read<AuthHub>();
return Card(
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'Auth Status: ${auth.isLoggedIn.value ? "Logged In" : "Logged Out"}'),
Text('Username: ${auth.username.value}'),
const SizedBox(height: 8),
ElevatedButton(
onPressed: () {
if (auth.isLoggedIn.value) {
auth.logout();
} else {
auth.login('John Doe');
}
},
child:
Text(auth.isLoggedIn.value ? 'Logout' : 'Login'),
),
],
),
),
);
},
),
const SizedBox(height: 16),
Sink<double>(
pipe: context.read<SettingsHub>().fontSize,
builder: (context, fontSize) {
return Card(
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text('Font Size: ${fontSize.toInt()}',
style: TextStyle(fontSize: fontSize)),
const SizedBox(height: 8),
Row(
children: [
ElevatedButton(
onPressed: () => context
.read<SettingsHub>()
.decreaseFontSize(),
child: const Text('A-'),
),
const SizedBox(width: 8),
ElevatedButton(
onPressed: () => context
.read<SettingsHub>()
.increaseFontSize(),
child: const Text('A+'),
),
],
),
],
),
),
);
},
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 8.1: HubProvider.value (External Lifecycle)
// ============================================================================
//
// Use HubProvider.value when you want to manage the hub's lifecycle yourself.
// The hub is NOT automatically disposed when the provider is removed.
//
// Use cases:
// - Share a hub instance across multiple routes
// - When you need to keep state alive beyond widget lifecycle
// - Integration with existing dependency injection systems
// - Testing scenarios where you provide mock instances
// ============================================================================
class HubProviderValueExample extends StatefulWidget {
const HubProviderValueExample({super.key});
@override
State<HubProviderValueExample> createState() =>
_HubProviderValueExampleState();
}
class _HubProviderValueExampleState extends State<HubProviderValueExample> {
int _toggleCount = 0;
@override
Widget build(BuildContext context) {
return Sink(
pipe: context.read<ThemeHub>().isDark,
builder: (context, isDark) {
return MaterialApp(
theme: isDark ? ThemeData.dark() : ThemeData.light(),
home: Scaffold(
appBar: AppBar(
title: const Text('HubProvider.value Example'),
leading: IconButton(
icon: const Icon(Icons.arrow_back),
onPressed: () => Navigator.of(context).pop(),
),
),
body: SingleChildScrollView(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
// Info card
Card(
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(
children: [
Icon(Icons.info_outline,
color: Colors.orange.shade700),
const SizedBox(width: 8),
const Text(
'HubProvider.value',
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
),
),
],
),
const SizedBox(height: 12),
const Text(
'This example uses HubProvider.value constructor.\n\n'
'✅ Hub was created BEFORE the provider\n'
'✅ You manage the lifecycle (not auto-disposed)\n'
'✅ Perfect for sharing state across routes\n'
'✅ Useful for testing with mock instances',
style: TextStyle(fontSize: 14),
),
],
),
),
),
const SizedBox(height: 20),
// Theme toggle
Card(
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
children: [
Text(
isDark ? '🌙 Dark Mode' : '☀️ Light Mode',
style: const TextStyle(fontSize: 32),
),
const SizedBox(height: 16),
Text(
'Toggled $_toggleCount times',
style: TextStyle(
fontSize: 16,
color: Colors.grey.shade600,
),
),
const SizedBox(height: 16),
ElevatedButton.icon(
onPressed: () {
setState(() => _toggleCount++);
context.read<ThemeHub>().toggle();
},
icon: const Icon(Icons.brightness_6),
label: const Text('Toggle Theme'),
),
],
),
),
),
const SizedBox(height: 20),
// Code example
Card(
child: const Padding(
padding: EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'📝 How this example was created:',
style: TextStyle(
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
SizedBox(height: 12),
Text(
'// 1. Create the hub FIRST\n'
'final myHub = ThemeHub();\n\n'
'// 2. Provide it using .value\n'
'HubProvider<ThemeHub>.value(\n'
' value: myHub, // Pass existing instance\n'
' child: MyApp(),\n'
')\n\n'
'// 3. You must dispose it manually\n'
'// when you\'re done:\n'
'myHub.dispose();',
style: TextStyle(
fontFamily: 'monospace',
fontSize: 12,
),
),
],
),
),
),
const SizedBox(height: 20),
// Comparison
Card(
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Text(
'HubProvider.create vs .value',
style: TextStyle(
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
const SizedBox(height: 12),
_buildComparisonRow(
'Lifecycle Management',
'Automatic',
'Manual',
),
_buildComparisonRow(
'Auto-dispose',
'Yes ✅',
'No ❌',
),
_buildComparisonRow(
'Created',
'By provider',
'Before provider',
),
_buildComparisonRow(
'Use case',
'Most cases',
'Shared state',
),
],
),
),
),
],
),
),
),
);
},
);
}
Widget _buildComparisonRow(String label, String create, String value) {
return Padding(
padding: const EdgeInsets.symmetric(vertical: 4),
child: Row(
children: [
SizedBox(
width: 140,
child: Text(
label,
style: const TextStyle(fontWeight: FontWeight.w500),
),
),
Expanded(
child: Row(
children: [
Expanded(
child: Text(
create,
style: const TextStyle(fontSize: 12),
),
),
Expanded(
child: Text(
value,
style: const TextStyle(fontSize: 12),
),
),
],
),
),
],
),
);
}
}
// ============================================================================
// EXAMPLE 8.2: MultiHubProvider with Existing Instances
// ============================================================================
//
// MultiHubProvider can accept both:
// - Factory functions: () => MyHub() (will be created and disposed)
// - Hub instances: myHub (will NOT be disposed)
//
// Mix and match as needed for your use case!
// ============================================================================
class MultiHubProviderValueExample extends StatelessWidget {
const MultiHubProviderValueExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('MultiHubProvider with Values'),
backgroundColor: Colors.teal.shade700,
),
body: SingleChildScrollView(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
// Info card
Card(
color: Colors.teal.shade50,
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(
children: [
Icon(Icons.layers, color: Colors.teal.shade700),
const SizedBox(width: 8),
const Text(
'Pre-created Hub Instances',
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
),
),
],
),
const SizedBox(height: 12),
const Text(
'Both hubs in this example were created BEFORE '
'the MultiHubProvider:\n\n'
'✅ Full control over initialization\n'
'✅ Can configure hubs before providing them\n'
'✅ Easy to test with dependency injection\n'
'✅ You manage disposal manually',
style: TextStyle(fontSize: 14),
),
],
),
),
),
const SizedBox(height: 20),
// Auth Hub section
Well(
pipes: [
context.read<AuthHub>().isLoggedIn,
context.read<AuthHub>().username,
],
builder: (context) {
final auth = context.read<AuthHub>();
return Card(
elevation: 2,
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(
children: [
Icon(
Icons.account_circle,
color: auth.isLoggedIn.value
? Colors.green
: Colors.grey,
),
const SizedBox(width: 8),
const Text(
'Auth Hub (Pre-created)',
style: TextStyle(
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
],
),
const Divider(),
Text(
'Status: ${auth.isLoggedIn.value ? "Logged In ✅" : "Logged Out ❌"}',
style: const TextStyle(fontSize: 16),
),
Text(
'User: ${auth.username.value}',
style: TextStyle(
fontSize: 14,
color: Colors.grey.shade700,
),
),
const SizedBox(height: 12),
ElevatedButton.icon(
onPressed: () {
if (auth.isLoggedIn.value) {
auth.logout();
} else {
auth.login('Alice');
}
},
icon: Icon(
auth.isLoggedIn.value ? Icons.logout : Icons.login,
),
label: Text(
auth.isLoggedIn.value ? 'Logout' : 'Login',
),
),
],
),
),
);
},
),
const SizedBox(height: 16),
// Settings Hub section
Sink<double>(
pipe: context.read<SettingsHub>().fontSize,
builder: (context, fontSize) {
return Card(
elevation: 2,
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Row(
children: [
Icon(Icons.settings, color: Colors.blue),
SizedBox(width: 8),
Text(
'Settings Hub (Pre-created)',
style: TextStyle(
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
],
),
const Divider(),
Text(
'Font Size: ${fontSize.toInt()}px',
style: TextStyle(fontSize: fontSize),
),
const SizedBox(height: 12),
Row(
children: [
ElevatedButton.icon(
onPressed: () => context
.read<SettingsHub>()
.decreaseFontSize(),
icon: const Icon(Icons.text_decrease),
label: const Text('Smaller'),
),
const SizedBox(width: 8),
ElevatedButton.icon(
onPressed: () => context
.read<SettingsHub>()
.increaseFontSize(),
icon: const Icon(Icons.text_increase),
label: const Text('Larger'),
),
],
),
],
),
),
);
},
),
const SizedBox(height: 20),
// Code example
Card(
color: Colors.grey.shade100,
child: const Padding(
padding: EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'📝 Code for this example:',
style: TextStyle(
fontSize: 16,
fontWeight: FontWeight.bold,
),
),
SizedBox(height: 12),
Text(
'// 1. Create hub instances first\n'
'final authHub = AuthHub();\n'
'final settingsHub = SettingsHub();\n\n'
'// 2. Pass them to MultiHubProvider\n'
'MultiHubProvider(\n'
' hubs: [\n'
' authHub, // Existing instance\n'
' settingsHub, // Existing instance\n'
' ],\n'
' child: MyApp(),\n'
')\n\n'
'// You can also mix factories and values:\n'
'MultiHubProvider(\n'
' hubs: [\n'
' authHub, // Existing (no dispose)\n'
' () => ThemeHub(), // Factory (auto-dispose)\n'
' ],\n'
' child: MyApp(),\n'
')',
style: TextStyle(
fontFamily: 'monospace',
fontSize: 12,
),
),
],
),
),
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 9: Scoped vs Global
// ============================================================================
class CounterGlobalHub extends Hub {
late final count = pipe(0);
void increment() => count.value++;
}
class ScopedVsGlobalExample extends StatelessWidget {
const ScopedVsGlobalExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Scoped vs Global')),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text('Global Hub (survives navigation):'),
Sink(
pipe: context.read<CounterGlobalHub>().count,
builder: (context, value) => Text('Global Count: $value',
style: const TextStyle(fontSize: 24)),
),
ElevatedButton(
onPressed: () => context.read<CounterGlobalHub>().increment(),
child: const Text('Increment Global'),
),
const SizedBox(height: 32),
ElevatedButton(
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (_) => const ScopedScreen()),
);
},
child: const Text('Open Scoped Screen'),
),
],
),
),
);
}
}
class ScopedScreen extends StatelessWidget {
const ScopedScreen({super.key});
@override
Widget build(BuildContext context) {
return HubProvider(
create: () => CounterGlobalHub(), // New instance, disposed on pop
child: Scaffold(
appBar: AppBar(title: const Text('Scoped Screen')),
body: Center(
child: Comp(),
),
),
);
}
}
class Comp extends StatelessWidget {
const Comp({
super.key,
});
@override
Widget build(BuildContext context) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text('Scoped Hub (disposed on back):'),
Sink(
pipe: context.read<CounterGlobalHub>().count,
builder: (context, value) => Text('Scoped Count: $value',
style: const TextStyle(fontSize: 24)),
),
ElevatedButton(
onPressed: () => context.read<CounterGlobalHub>().increment(),
child: const Text('Increment Scoped'),
),
],
);
}
}
// ============================================================================
// EXAMPLE 10: Computed Values (Getters)
// ============================================================================
class ShoppingHub extends Hub {
late final items = pipe<List<String>>([]);
late final pricePerItem = pipe(9.99);
// Computed values using getters
int get itemCount => items.value.length;
double get total => itemCount * pricePerItem.value;
String get summary => '$itemCount items - \$${total.toStringAsFixed(2)}';
void addItem(String item) {
items.value = [...items.value, item];
}
void clear() {
items.value = [];
}
}
class ComputedValuesExample extends StatelessWidget {
const ComputedValuesExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Computed Values')),
body: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Text('Use getters for computed/derived state:',
style: TextStyle(fontSize: 16)),
const SizedBox(height: 24),
Well(
pipes: [
context.read<ShoppingHub>().items,
context.read<ShoppingHub>().pricePerItem,
],
builder: (context) {
final hub = context.read<ShoppingHub>();
return Card(
color: Colors.blue[50],
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text('Items: ${hub.itemCount}',
style: const TextStyle(fontSize: 18)),
Text(
'Price per item: \$${hub.pricePerItem.value.toStringAsFixed(2)}'),
const Divider(),
Text(
'Total: \$${hub.total.toStringAsFixed(2)}',
style: const TextStyle(
fontSize: 24, fontWeight: FontWeight.bold),
),
],
),
),
);
},
),
const SizedBox(height: 16),
Expanded(
child: Sink(
pipe: context.read<ShoppingHub>().items,
builder: (context, items) {
if (items.isEmpty) {
return const Center(child: Text('No items yet'));
}
return ListView.builder(
itemCount: items.length,
itemBuilder: (context, index) {
return ListTile(
leading: const Icon(Icons.shopping_cart),
title: Text(items[index]),
);
},
);
},
),
),
Row(
children: [
Expanded(
child: ElevatedButton(
onPressed: () {
final hub = context.read<ShoppingHub>();
hub.addItem('Item ${hub.itemCount + 1}');
},
child: const Text('Add Item'),
),
),
const SizedBox(width: 8),
ElevatedButton(
onPressed: () => context.read<ShoppingHub>().clear(),
child: const Text('Clear'),
),
],
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 11: Async Operations
// ============================================================================
// User Profile Model - Regular class, NOT a Pipe!
class UserProfile {
final String id;
final String name;
final String email;
final String phone;
final String address;
final String city;
final String country;
final String occupation;
final String bio;
final String joinedDate;
// Note: gender and age will be managed separately as Pipes for reactivity
UserProfile({
required this.id,
required this.name,
required this.email,
required this.phone,
required this.address,
required this.city,
required this.country,
required this.occupation,
required this.bio,
required this.joinedDate,
});
}
class DataHub extends Hub {
late final isLoading = pipe(false);
late final error = pipe<String?>(null);
// Profile data as a Pipe for reactivity!
late final userProfile = pipe<UserProfile?>(null);
// Only editable fields are Pipes for granular reactivity!
late final gender = pipe<String>('Male');
late final age = pipe<int>(25);
Future<void> fetchUserProfile() async {
isLoading.value = true;
error.value = null;
try {
// Simulate API call
await Future.delayed(const Duration(seconds: 2));
// Load profile data into Pipe
userProfile.value = UserProfile(
id: 'USR-12345',
name: 'John Doe',
email: 'john.doe@example.com',
phone: '+1 (555) 123-4567',
address: '123 Main Street, Apt 4B',
city: 'San Francisco',
country: 'United States',
occupation: 'Software Engineer',
bio: 'Passionate about Flutter and reactive programming. '
'Love building clean, performant applications.',
joinedDate: 'January 15, 2023',
);
// Load reactive fields (Pipes)
gender.value = 'Male';
age.value = 28;
} catch (e) {
error.value = e.toString();
} finally {
isLoading.value = false;
}
}
}
class AsyncExample extends StatefulWidget {
const AsyncExample({super.key});
@override
State<AsyncExample> createState() => _AsyncExampleState();
}
class _AsyncExampleState extends State<AsyncExample> {
@override
void initState() {
super.initState();
// Fetch user profile immediately after the first frame is rendered
context.read<DataHub>().fetchUserProfile();
}
@override
Widget build(BuildContext context) {
final hub = context.read<DataHub>();
return Scaffold(
appBar: AppBar(title: const Text('User Profile - Async Demo')),
body: Stack(
children: [
// Bottom Layer: Profile Screen (static data + reactive fields)
_ProfileScreen(hub: hub),
// Top Layer: Loading Overlay (Sink for loading state)
Sink(
pipe: hub.isLoading,
builder: (context, isLoading) {
if (!isLoading) return const SizedBox.shrink();
return Container(
color: const Color.fromARGB(255, 197, 228, 213),
child: const Center(
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
CircularProgressIndicator(
valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
strokeWidth: 3,
),
SizedBox(height: 16),
Text(
'Loading Profile...',
style: TextStyle(
color: Colors.white,
fontSize: 16,
fontWeight: FontWeight.w500,
),
),
],
),
),
);
},
),
],
),
);
}
}
class _ProfileScreen extends StatelessWidget {
final DataHub hub;
const _ProfileScreen({required this.hub});
@override
Widget build(BuildContext context) {
// Use Sink to reactively rebuild when profile data is loaded!
return Sink(
pipe: hub.userProfile,
builder: (context, profile) {
if (profile == null) {
return const Center(
child: Text('No profile data loaded'),
);
}
return SingleChildScrollView(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
// Header
const Text(
'📱 User Profile',
style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
),
const SizedBox(height: 8),
const Text(
'Profile data loaded via Pipe! Gender & Age use separate Sinks for independent updates.',
style: TextStyle(fontSize: 12, color: Colors.grey),
),
const Divider(height: 32),
const SizedBox(height: 16),
_buildField('ID', profile.id, Icons.badge),
_buildField('Name', profile.name, Icons.person),
_buildField('Email', profile.email, Icons.email),
_buildField('Phone', profile.phone, Icons.phone),
_buildField('Address', profile.address, Icons.home),
_buildField('City', profile.city, Icons.location_city),
_buildField('Country', profile.country, Icons.flag),
_buildField('Occupation', profile.occupation, Icons.work),
_buildField('Bio', profile.bio, Icons.description, maxLines: 3),
_buildField('Joined', profile.joinedDate, Icons.calendar_today),
const SizedBox(height: 16),
// Gender - Reactive with Sink
Row(
children: [
const Icon(Icons.wc, size: 20, color: Colors.grey),
const SizedBox(width: 12),
const Text('Gender:',
style: TextStyle(fontWeight: FontWeight.w600)),
const SizedBox(width: 8),
],
),
const SizedBox(height: 16),
Sink(
pipe: hub.gender,
builder: (context, gender) {
return Row(
children: [
...['Male', 'Female', 'Other'].map((g) => Padding(
padding: const EdgeInsets.only(right: 8),
child: ChoiceChip(
label: Text(g),
selected: gender == g,
onSelected: (selected) {
if (selected) hub.gender.value = g;
},
),
)),
],
);
},
),
const SizedBox(height: 16),
// Age - Reactive with Sink
Row(
children: [
const Icon(Icons.cake, size: 20, color: Colors.grey),
const SizedBox(width: 12),
const Text('Age:',
style: TextStyle(fontWeight: FontWeight.w600)),
const SizedBox(width: 8),
Sink(
pipe: hub.age,
builder: (context, age) {
return Row(
children: [
Text(
'$age years',
style: const TextStyle(
fontSize: 24,
fontWeight: FontWeight.bold,
color: Colors.green,
),
),
const SizedBox(width: 16),
Column(
children: [
IconButton(
onPressed: () => hub.age.value++,
icon: const Icon(Icons.add_circle),
color: Colors.green,
),
IconButton(
onPressed: () {
if (hub.age.value > 1) hub.age.value--;
},
icon: const Icon(Icons.remove_circle),
color: Colors.red,
),
],
),
],
);
},
),
],
),
const SizedBox(height: 16),
Container(
padding: const EdgeInsets.all(12),
decoration: BoxDecoration(
color: Colors.amber.shade50,
borderRadius: BorderRadius.circular(8),
border: Border.all(color: Colors.amber.shade200),
),
child: const Row(
children: [
Icon(Icons.tips_and_updates, size: 16, color: Colors.amber),
SizedBox(width: 8),
Expanded(
child: Text(
'Try changing Gender or Age - ONLY those Sinks rebuild!\n'
'The outer Sink (userProfile) and static fields stay untouched. 🚀\n'
'Reload → Outer Sink rebuilds all. Edit field → Only that Sink rebuilds!',
style: TextStyle(fontSize: 11, color: Colors.black87),
),
),
],
),
),
const SizedBox(height: 24),
// Reload Button
Center(
child: ElevatedButton.icon(
onPressed: hub.fetchUserProfile,
icon: const Icon(Icons.refresh),
label: const Text('Reload Profile'),
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.symmetric(
horizontal: 24,
vertical: 12,
),
),
),
),
],
),
);
},
);
}
Widget _buildField(String label, String value, IconData icon,
{int? maxLines}) {
return Padding(
padding: const EdgeInsets.only(bottom: 12),
child: Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Column(
children: [
const SizedBox(height: 12),
Icon(icon, size: 20, color: Colors.grey),
],
),
const SizedBox(width: 12),
Expanded(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'$label:',
style: const TextStyle(
fontWeight: FontWeight.w600,
fontSize: 12,
color: Colors.grey,
),
),
Text(
value,
style: const TextStyle(fontSize: 14),
maxLines: maxLines,
),
],
),
),
],
),
);
}
}
// ============================================================================
// EXAMPLE 12: Form Management
// ============================================================================
class FormHub extends Hub {
late final name = pipe('');
late final email = pipe('');
late final age = pipe('');
// Validation computed values
bool get isNameValid => name.value.length >= 3;
bool get isEmailValid => email.value.contains('@');
bool get isAgeValid =>
int.tryParse(age.value) != null && int.parse(age.value) >= 18;
bool get isFormValid => isNameValid && isEmailValid && isAgeValid;
void submit() {
if (isFormValid) {
// Handle submission
}
}
}
class FormExample extends StatelessWidget {
const FormExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Form Management')),
body: Padding(
padding: const EdgeInsets.all(16),
child: Column(
children: [
TextField(
decoration:
const InputDecoration(labelText: 'Name (min 3 chars)'),
onChanged: (value) => context.read<FormHub>().name.value = value,
),
Sink(
pipe: context.read<FormHub>().name,
builder: (context, value) {
final hub = context.read<FormHub>();
return Text(
hub.isNameValid ? '✓ Valid' : '✗ Too short',
style: TextStyle(
color: hub.isNameValid ? Colors.green : Colors.red,
fontSize: 12),
);
},
),
const SizedBox(height: 16),
TextField(
decoration: const InputDecoration(labelText: 'Email'),
onChanged: (value) => context.read<FormHub>().email.value = value,
),
Sink(
pipe: context.read<FormHub>().email,
builder: (context, value) {
final hub = context.read<FormHub>();
return Text(
hub.isEmailValid ? '✓ Valid' : '✗ Invalid email',
style: TextStyle(
color: hub.isEmailValid ? Colors.green : Colors.red,
fontSize: 12),
);
},
),
const SizedBox(height: 16),
TextField(
decoration: const InputDecoration(labelText: 'Age (18+)'),
keyboardType: TextInputType.number,
onChanged: (value) => context.read<FormHub>().age.value = value,
),
Sink(
pipe: context.read<FormHub>().age,
builder: (context, value) {
final hub = context.read<FormHub>();
return Text(
hub.isAgeValid ? '✓ Valid' : '✗ Must be 18+',
style: TextStyle(
color: hub.isAgeValid ? Colors.green : Colors.red,
fontSize: 12),
);
},
),
const SizedBox(height: 24),
Well(
pipes: [
context.read<FormHub>().name,
context.read<FormHub>().email,
context.read<FormHub>().age,
],
builder: (context) {
final hub = context.read<FormHub>();
return ElevatedButton(
onPressed: hub.isFormValid ? () => hub.submit() : null,
child: const Text('Submit'),
);
},
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE 13: Class Type in Pipe
// ============================================================================
/// User profile model class (MUTABLE)
/// This class demonstrates using mutable objects with Pipe.forceUpdate()
class MutableUserProfile {
String name;
int age;
String email;
String bio;
bool isPremium;
MutableUserProfile({
required this.name,
required this.age,
required this.email,
required this.bio,
required this.isPremium,
});
}
class UserProfileHub extends Hub {
late final user = pipe<MutableUserProfile>(
MutableUserProfile(
name: 'John Doe',
age: 28,
email: 'john@example.com',
bio: 'Flutter developer',
isPremium: false,
),
);
/// Update specific fields by mutating the object and calling forceUpdate
/// This demonstrates using mutable objects with Pipe
void updateName(String name) {
user.value.name = name;
user.pump(user.value); // Force rebuild even though reference didn't change
}
void updateAge(int age) {
user.value.age++;
user.pump(user.value);
}
void updateEmail(String email) {
user.value.email = email;
user.pump(user.value);
}
void updateBio(String bio) {
user.value.bio = bio;
user.pump(user.value);
}
void togglePremium() {
user.value.isPremium = !user.value.isPremium;
user.pump(user.value);
}
}
class ClassTypeExample extends StatelessWidget {
const ClassTypeExample({super.key});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Class Type in Pipe')),
body: SingleChildScrollView(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Text(
'Using MUTABLE classes in Pipes:',
style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
),
const SizedBox(height: 16),
const Text(
'Entire object is stored in one Pipe. Mutate fields and call forceUpdate().',
style: TextStyle(fontSize: 14, color: Colors.grey),
),
const SizedBox(height: 24),
// Display user profile
Sink(
pipe: context.read<UserProfileHub>().user,
builder: (context, user) {
return Card(
elevation: 4,
child: Padding(
padding: const EdgeInsets.all(16),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(
children: [
CircleAvatar(
radius: 30,
backgroundColor:
user.isPremium ? Colors.amber : Colors.grey,
child: Text(
user.name.isNotEmpty ? user.name[0] : '?',
style: const TextStyle(
fontSize: 24, color: Colors.white),
),
),
const SizedBox(width: 16),
Expanded(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(
children: [
Text(
user.name,
style: const TextStyle(
fontSize: 20,
fontWeight: FontWeight.bold,
),
),
if (user.isPremium)
const Padding(
padding: EdgeInsets.only(left: 8),
child: Icon(Icons.star,
color: Colors.amber, size: 20),
),
],
),
Text(
'${user.age} years old',
style: const TextStyle(color: Colors.grey),
),
],
),
),
],
),
const Divider(height: 24),
Row(
children: [
const Icon(Icons.email,
size: 16, color: Colors.grey),
const SizedBox(width: 8),
Text(user.email),
],
),
const SizedBox(height: 8),
Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
const Icon(Icons.info,
size: 16, color: Colors.grey),
const SizedBox(width: 8),
Expanded(child: Text(user.bio)),
],
),
],
),
),
);
},
),
const SizedBox(height: 32),
const Text(
'Update Methods:',
style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold),
),
const SizedBox(height: 16),
// Update name
TextField(
decoration: const InputDecoration(
labelText: 'Name',
border: OutlineInputBorder(),
),
onChanged: (value) {
context.read<UserProfileHub>().updateName(value);
},
),
const SizedBox(height: 12),
// Update email
TextField(
decoration: const InputDecoration(
labelText: 'Email',
border: OutlineInputBorder(),
),
onChanged: (value) {
context.read<UserProfileHub>().updateEmail(value);
},
),
const SizedBox(height: 12),
// Update bio
TextField(
decoration: const InputDecoration(
labelText: 'Bio',
border: OutlineInputBorder(),
),
maxLines: 2,
onChanged: (value) {
context.read<UserProfileHub>().updateBio(value);
},
),
const SizedBox(height: 24),
// Age buttons
Row(
children: [
const Text('Age: '),
IconButton(
icon: const Icon(Icons.remove),
onPressed: () {
final hub = context.read<UserProfileHub>();
final newAge = (hub.user.value.age - 1).clamp(0, 120);
hub.updateAge(newAge);
},
),
Sink(
pipe: context.read<UserProfileHub>().user,
builder: (context, user) => Text(
'${user.age}',
style: const TextStyle(
fontSize: 18, fontWeight: FontWeight.bold),
),
),
IconButton(
icon: const Icon(Icons.add),
onPressed: () {
final hub = context.read<UserProfileHub>();
final newAge = (hub.user.value.age + 1).clamp(0, 120);
hub.updateAge(newAge);
},
),
],
),
const SizedBox(height: 16),
// Premium toggle
ElevatedButton.icon(
onPressed: () => context.read<UserProfileHub>().togglePremium(),
icon: const Icon(Icons.star),
label: const Text('Toggle Premium Status'),
style: ElevatedButton.styleFrom(
minimumSize: const Size(double.infinity, 48),
),
),
const SizedBox(height: 32),
Container(
padding: const EdgeInsets.all(12),
decoration: BoxDecoration(
color: Colors.blue[50],
borderRadius: BorderRadius.circular(8),
),
child: const Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'💡 Key Points:',
style: TextStyle(fontWeight: FontWeight.bold),
),
SizedBox(height: 8),
Text('• Entire object stored in Pipe<UserProfile>'),
Text('• Mutate object fields directly'),
Text('• Call forceUpdate() to trigger Sink rebuild'),
Text('• Useful for mutable objects (e.g., from APIs)'),
Text('• Reference stays same, but UI updates'),
],
),
),
],
),
),
);
}
}
// ============================================================================
// EXAMPLE: HubListener - Conditional Side Effects
// ============================================================================
class TargetCounterHub extends Hub {
late final count = pipe(0);
late final target = pipe(5);
late final VoidCallback _removeListener;
void onTargetReached(BuildContext context) {
_removeListener = addListener(() {
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(
content: Text('🎯 Target Reached!'),
backgroundColor: Colors.green,
duration: Duration(seconds: 2),
),
);
});
}
void increment() => count.value++;
void decrement() => count.value--;
void setTarget(int value) => target.value = value;
@override
void dispose() {
_removeListener();
super.dispose();
}
}
class HubListenerExample extends StatelessWidget {
const HubListenerExample({super.key});
@override
Widget build(BuildContext context) {
final hub = context.read<TargetCounterHub>();
hub.onTargetReached(context);
return Scaffold(
appBar: AppBar(
title: const Text('HubListener Example'),
backgroundColor: Colors.purple,
),
body: HubListener<TargetCounterHub>(
listenWhen: (hub) {
// Condition: when count equals target
return hub.count.value == hub.target.value;
},
onConditionMet: () {
// Side effect: show snackbar (NO rebuild!)
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(
content: Text('🎯🎯🎯 Target Reached!'),
backgroundColor: Colors.green,
duration: Duration(seconds: 2),
),
);
},
child: Padding(
padding: const EdgeInsets.all(24),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text(
'🎯 Target Counter',
style: TextStyle(
fontSize: 28,
fontWeight: FontWeight.bold,
),
),
const SizedBox(height: 40),
// Current count
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text(
'Count: ',
style: TextStyle(fontSize: 20),
),
Sink<int>(
pipe: hub.count,
builder: (context, count) => Text(
count.toString(),
style: const TextStyle(
fontSize: 48,
fontWeight: FontWeight.bold,
color: Colors.blue,
),
),
),
],
),
const SizedBox(height: 20),
// Target value
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
const Text(
'Target: ',
style: TextStyle(fontSize: 20),
),
Sink<int>(
pipe: hub.target,
builder: (context, target) => Text(
target.toString(),
style: const TextStyle(
fontSize: 48,
fontWeight: FontWeight.bold,
color: Colors.purple,
),
),
),
],
),
const SizedBox(height: 40),
// Counter buttons
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
ElevatedButton(
onPressed: hub.decrement,
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.all(20),
backgroundColor: Colors.red,
foregroundColor: Colors.white,
),
child: const Icon(Icons.remove, size: 32),
),
const SizedBox(width: 20),
ElevatedButton(
onPressed: hub.increment,
style: ElevatedButton.styleFrom(
padding: const EdgeInsets.all(20),
backgroundColor: Colors.green,
foregroundColor: Colors.white,
),
child: const Icon(Icons.add, size: 32),
),
],
),
const SizedBox(height: 40),
// Target selection
const Text(
'Set Target:',
style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
),
const SizedBox(height: 12),
Wrap(
spacing: 8,
runSpacing: 8,
alignment: WrapAlignment.center,
children: [3, 5, 10, 15, 20].map((value) {
return Sink<int>(
pipe: hub.target,
builder: (context, currentTarget) => OutlinedButton(
onPressed: () => hub.setTarget(value),
style: OutlinedButton.styleFrom(
backgroundColor: currentTarget == value
? Colors.purple.withOpacity(0.2)
: null,
side: BorderSide(
color: currentTarget == value
? Colors.purple
: Colors.grey,
width: 2,
),
),
child: Text(
value.toString(),
style: TextStyle(
fontSize: 18,
fontWeight: currentTarget == value
? FontWeight.bold
: FontWeight.normal,
),
),
),
);
}).toList(),
),
const Spacer(),
// Info box
Container(
padding: const EdgeInsets.all(16),
decoration: BoxDecoration(
color: Colors.blue[50],
borderRadius: BorderRadius.circular(8),
border: Border.all(color: Colors.blue[200]!),
),
child: const Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'💡 How HubListener works:',
style: TextStyle(fontWeight: FontWeight.bold),
),
SizedBox(height: 8),
Text('• Monitors ALL pipes in the hub'),
Text('• listenWhen: checks condition on every change'),
Text('• onConditionMet: executes when condition is true'),
Text('• Child widget NEVER rebuilds'),
Text('• Perfect for: snackbars, dialogs, navigation'),
],
),
),
],
),
),
),
);
}
}Metadata
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likes
0
points
333
downloads
Publisher
Weekly Downloads
Metadata
A lightweight, reactive state management library for Flutter with fine-grained reactivity and minimal boilerplate.
Repository (GitHub)
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Topics
#state-management #reactive #flutter #signals #controller
License
unknown (license)
