Add deeplink store sample (#1698)

* Adds deeplink store app

* push

* update md

* update

deeplink_store_example/lib/product_details.dart

@@ -0,0 +1,66 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+
+import 'model/products_repository.dart';
+import 'styles.dart';
+
+class ProductDetails extends StatelessWidget {
+  const ProductDetails({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final String currentId = GoRouterState.of(context).params['id']!;
+    final Product product = ProductsRepository.loadProduct(id: int.parse(currentId));
+    return Scaffold(
+      body: ListView(
+        children: <Widget>[
+          ProductPicture(product: product),
+          Styles.spacer,
+          Text(product.name, style: Styles.productPageItemName),
+          Styles.spacer,
+          Text('\$${product.price}', style: Styles.productPageItemPrice),
+          Styles.largeSpacer,
+        ],
+      ),
+    );
+  }
+}
+
+class ProductPicture extends StatelessWidget{
+  const ProductPicture({super.key, required this.product});
+
+  final Product product;
+
+  @override
+  Widget build(BuildContext context) {
+    return Stack(
+      children: [
+        LayoutBuilder(
+          builder: (BuildContext context, BoxConstraints constraints) {
+            return Image.asset(
+              product.assetName2X,
+              package: product.assetPackage,
+              fit: BoxFit.cover,
+              width: constraints.maxWidth,
+            );
+          },
+        ),
+        const BackButton(),
+      ],
+    );
+  }
+}