simple widget tree with managing data with each

lib/main.dart

@@ -1,18 +1,10 @@
 import 'package:flutter/material.dart';
 
+import './product_manager.dart';
+
 void main() => runApp(MyApp());
 
-class MyApp extends StatefulWidget {
+class MyApp extends StatelessWidget {
-  @override
-  State<StatefulWidget> createState() {
-    // TODO: implement createState
-    return _MyAppState();
-  }
-}
-
-class _MyAppState extends State<MyApp> {
-  List<String> _products = ['Test'];
-
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
@@ -22,27 +14,7 @@ class _MyAppState extends State<MyApp> {
       ),
       body: Column(
         children: [
-          Container(
+          ProductManager('Test'),
-              margin: EdgeInsets.all(10),
-              child: RaisedButton(
-                onPressed: () {
-                  setState(() {
-                    _products.add('Advanced Food Tester');
-                  });                  
-                },
-                child: Text('Click Me!'),
-              )),
-          Column(
-            children: _products
-                .map((elem) => Card(
-                        child: Column(
-                      children: <Widget>[
-                        Image.asset('assets/food.jpg'),
-                        Text(elem)
-                      ],
-                    )))
-                .toList(),
-          ),
         ],
       ),
     ));

lib/product_manager.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/material.dart';
+
+import './products.dart';
+
+class ProductManager extends StatefulWidget {
+  final String startingProduct;
+
+  ProductManager(this.startingProduct);
+
+  @override
+  State<StatefulWidget> createState() {
+    return _ProductManagerState();
+  }
+}
+
+class _ProductManagerState extends State<ProductManager> {
+  List<String> _products = [];
+
+  @override
+  void initState() {
+    super.initState();
+    _products.add(widget.startingProduct);    
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: [
+        Container(
+          margin: EdgeInsets.all(10),
+          child: RaisedButton(
+            onPressed: () {
+              setState(() {
+                _products.add('Advanced Food Tester');
+              });
+            },
+            child: Text('Click Me!'),
+          ),
+        ),
+        Products(_products),
+      ],
+    );
+  }
+}

lib/products.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+
+class Products extends StatelessWidget {
+  final List<String> products;
+
+  Products(this.products);
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: products
+          .map((elem) => Card(
+                  child: Column(
+                children: <Widget>[Image.asset('assets/food.jpg'), Text(elem)],
+              )))
+          .toList(),
+    );
+  }
+}