feat: Update example template to use more modern Flame constructs

Author: luanpotter

bricks/example/__brick__/lib/main.dart

@@ -12,39 +12,40 @@ void main() {
   runApp(GameWidget(game: MyGame()));
 }
 
-class MyGame extends FlameGame with TapCallbacks {
+class MyGame extends FlameGame<MyWorld> {
+  MyGame() : super(world: MyWorld());
+}
+
+class MyWorld extends World {
   late final MyComponent myComponent;
 
   @override
   Future<void> onLoad() async {
-    await world.add(myComponent = MyComponent());
+    await add(myComponent = MyComponent());
     return super.onLoad();
   }
-
-  @override
-  void onTapUp(TapUpEvent event) {
-    myComponent.speed.x = -1 + 2 * _rng.nextDouble();
-    myComponent.speed.y = -1 + 2 * _rng.nextDouble();
-  }
 }
 
-class MyComponent extends PositionComponent with HasGameRef<MyGame> {
-  static final _paint = BasicPalette.white.paint();
+class MyComponent extends RectangleComponent with TapCallbacks {
   final Vector2 speed = Vector2.zero();
 
+  @override
+  final Paint paint = BasicPalette.magenta.paint();
+
   MyComponent()
-      : super(
+      : super.square(
+          size: 32,
           anchor: Anchor.center,
-          size: Vector2.all(32),
         );
 
   @override
-  void render(Canvas c) {
-    c.drawRect(size.toRect(), _paint);
+  void update(double dt) {
+    position += speed * 32.0 * dt;
   }
 
   @override
-  void update(double dt) {
-    position += speed * 32.0 * dt;
+  void onTapUp(TapUpEvent event) {
+    speed.x = -1 + 2 * _rng.nextDouble();
+    speed.y = -1 + 2 * _rng.nextDouble();
   }
 }

bricks/example/__brick__/test/widget_test.dart

@@ -10,13 +10,15 @@ void main() {
   myGame.testGameWidget(
     'game will load its child',
     verify: (game, tester) async {
-      game.update(0.0);
+      await tester.pumpWidget(GameWidget(game: game));
 
-      expect(game.children.length, 1);
-      expect(game.myComponent.speed, Vector2.zero());
+      expect(game.world.children.length, 1);
+      expect(game.world.myComponent.speed, Vector2.zero());
 
       await tester.tapAt(const Offset(10, 10));
-      expect(game.myComponent.speed, isNot(equals(Vector2.zero())));
+      await tester.pump(const Duration(milliseconds: 100));
+
+      expect(game.world.myComponent.speed, isNot(equals(Vector2.zero())));
     },
   );
 }