beauty builders

lib/main.dart

@@ -20,32 +20,68 @@ class MyApp extends StatelessWidget {
   }
 }
 
-abstract class ShapeFactory {
-  Widget build(Size size, Color color);
-}
-
-class SquareFactory extends ShapeFactory {
-  @override
-  Widget build(Size size, Color color) {
-    return SizedBox.fromSize(
-      size: size,
-      child: Container(color: color),
+///
+/// Shape Builder
+///
+abstract class ShapeBuilder {
+  Widget build(Size size, Widget child) {
+    return Container(
+      height: size.height,
+      width: size.width,
+      decoration: BoxDecoration(shape: boxShape, color: shapeColor),
+      child: Center(child: child),
     );
   }
+
+  BoxShape get boxShape;
+  Color get shapeColor;
 }
 
-class CircleFactory extends ShapeFactory {
+class RedSquareBuilder extends ShapeBuilder {
   @override
-  Widget build(Size size, Color color) {
-    return SizedBox.fromSize(
-      size: size,
-      child: Container(
-        decoration: BoxDecoration(shape: BoxShape.circle, color: color),
-      ),
-    );
-  }
+  BoxShape get boxShape => BoxShape.rectangle;
+
+  @override
+  Color get shapeColor => Colors.red;
 }
 
+class BlueCircleBuilder extends ShapeBuilder {
+  @override
+  BoxShape get boxShape => BoxShape.circle;
+
+  @override
+  Color get shapeColor => Colors.blue;
+}
+
+///
+/// Message Builder (Writer seemed appropriate)
+///
+abstract class MessageWriter {
+  Text write(String text);
+}
+
+class HotMessageWriter extends MessageWriter {
+  @override
+  Text write(String text) => Text(text, style: const TextStyle(fontWeight: FontWeight.bold, fontSize: 18));
+}
+
+class ColdMessageWriter extends MessageWriter {
+  @override
+  Text write(String text) => Text(text, style: const TextStyle(color: Colors.white, fontSize: 14));
+}
+
+final List<ShapeBuilder> builders = [
+  RedSquareBuilder(),
+  BlueCircleBuilder(),
+  RedSquareBuilder(),
+];
+
+final List<MessageWriter> writers = [
+  ColdMessageWriter(),
+  HotMessageWriter(),
+  HotMessageWriter(),
+];
+
 class MyHomePage extends StatefulWidget {
   const MyHomePage({super.key});
 
@@ -54,40 +90,24 @@ class MyHomePage extends StatefulWidget {
 }
 
 class _MyHomePageState extends State<MyHomePage> {
-  final List<ShapeFactory> shapeFactories = [CircleFactory(), SquareFactory()];
-  int factoryIndex = 0;
-  ShapeFactory get factory => shapeFactories[factoryIndex];
-
-  void swapFactories() {
-    if (factoryIndex == 0) {
-      setState(() => factoryIndex = 1);
-      return;
-    }
-    setState(() => factoryIndex = 0);
-  }
-
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
         backgroundColor: Theme.of(context).colorScheme.inversePrimary,
-        title: const Text('Abstract Factory'),
+        title: const Text('Builders'),
       ),
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
-            const Text('Abstract Factories!!'),
-            Text('Using ${shapeFactories[factoryIndex].runtimeType.toString()}'),
+            const Text('Builders!!'),
             ...List.generate(
-                3,
-                (index) => factory.build(
-                      Size(20.0 * (index + 1), 30.0 * (index + 1)),
-                      [Colors.red, Colors.green, Colors.blue][index],
-                    )),
-            ElevatedButton(
-              onPressed: () => swapFactories(),
-              child: const Text('Swap Factories'),
+              3,
+              (index) => builders[index].build(
+                Size(80.0 * (index + 1), 90.0 * (index + 1)),
+                writers[index].write('build ${index + 1}'),
+              ),
             ),
           ],
         ),