98 lines
2.4 KiB
Dart
98 lines
2.4 KiB
Dart
import 'package:flutter/material.dart';
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void main() {
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runApp(const MyApp());
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}
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class MyApp extends StatelessWidget {
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const MyApp({super.key});
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@override
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Widget build(BuildContext context) {
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return MaterialApp(
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title: 'Flutter Demo',
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theme: ThemeData(
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colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
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useMaterial3: true,
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),
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home: const MyHomePage(),
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);
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}
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}
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abstract class ShapeFactory {
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Widget build(Size size, Color color);
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}
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class SquareFactory extends ShapeFactory {
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@override
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Widget build(Size size, Color color) {
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return SizedBox.fromSize(
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size: size,
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child: Container(color: color),
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);
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}
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}
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class CircleFactory extends ShapeFactory {
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@override
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Widget build(Size size, Color color) {
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return SizedBox.fromSize(
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size: size,
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child: Container(
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decoration: BoxDecoration(shape: BoxShape.circle, color: color),
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),
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);
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}
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}
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class MyHomePage extends StatefulWidget {
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const MyHomePage({super.key});
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@override
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State<MyHomePage> createState() => _MyHomePageState();
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}
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class _MyHomePageState extends State<MyHomePage> {
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final List<ShapeFactory> shapeFactories = [CircleFactory(), SquareFactory()];
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int factoryIndex = 0;
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ShapeFactory get factory => shapeFactories[factoryIndex];
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void swapFactories() {
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if (factoryIndex == 0) {
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setState(() => factoryIndex = 1);
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return;
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}
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setState(() => factoryIndex = 0);
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}
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@override
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Widget build(BuildContext context) {
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return Scaffold(
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appBar: AppBar(
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backgroundColor: Theme.of(context).colorScheme.inversePrimary,
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title: const Text('Abstract Factory'),
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),
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body: Center(
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child: Column(
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mainAxisAlignment: MainAxisAlignment.center,
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children: <Widget>[
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const Text('Abstract Factories!!'),
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Text('Using ${shapeFactories[factoryIndex].runtimeType.toString()}'),
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...List.generate(
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3,
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(index) => factory.build(
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Size(20.0 * (index + 1), 30.0 * (index + 1)),
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[Colors.red, Colors.green, Colors.blue][index],
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)),
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ElevatedButton(
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onPressed: () => swapFactories(),
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child: const Text('Swap Factories'),
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),
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],
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),
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),
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);
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}
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}
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