Layout example: ListView (#2309)

examples/layout/grid_and_list/lib/main.dart

@@ -0,0 +1,72 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart' show debugPaintSizeEnabled;
+
+void main() {
+  debugPaintSizeEnabled = false; // Set to true for visual layout
+  runApp(MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  static final showGrid = true; // Set to false to show ListView
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Flutter layout demo',
+      home: Scaffold(
+        appBar: AppBar(
+          title: Text('Flutter layout demo'),
+        ),
+        body: Center(child: showGrid ? _buildGrid() : _buildList()),
+      ),
+    );
+  }
+
+  // #docregion grid
+  Widget _buildGrid() => GridView.extent(
+      maxCrossAxisExtent: 150,
+      padding: const EdgeInsets.all(4),
+      mainAxisSpacing: 4,
+      crossAxisSpacing: 4,
+      children: _buildGridTileList(30));
+
+  // The images are saved with names pic0.jpg, pic1.jpg...pic29.jpg.
+  // The List.generate() constructor allows an easy way to create
+  // a list when objects have a predictable naming pattern.
+  List<Container> _buildGridTileList(int count) => List.generate(
+      count, (i) => Container(child: Image.asset('images/pic$i.jpg')));
+  // #enddocregion grid
+
+  // #docregion list
+  Widget _buildList() => ListView(
+        children: [
+          _tile('CineArts at the Empire', '85 W Portal Ave', Icons.theaters),
+          _tile('The Castro Theater', '429 Castro St', Icons.theaters),
+          _tile('Alamo Drafthouse Cinema', '2550 Mission St', Icons.theaters),
+          _tile('Roxie Theater', '3117 16th St', Icons.theaters),
+          _tile('United Artists Stonestown Twin', '501 Buckingham Way',
+              Icons.theaters),
+          _tile('AMC Metreon 16', '135 4th St #3000', Icons.theaters),
+          Divider(),
+          _tile('K\'s Kitchen', '757 Monterey Blvd', Icons.restaurant),
+          _tile('Emmy\'s Restaurant', '1923 Ocean Ave', Icons.restaurant),
+          _tile(
+              'Chaiya Thai Restaurant', '272 Claremont Blvd', Icons.restaurant),
+          _tile('La Ciccia', '291 30th St', Icons.restaurant),
+        ],
+      );
+
+  ListTile _tile(String title, String subtitle, IconData icon) => ListTile(
+        title: Text(title,
+            style: TextStyle(
+              fontWeight: FontWeight.w500,
+              fontSize: 20,
+            )),
+        subtitle: Text(subtitle),
+        leading: Icon(
+          icon,
+          color: Colors.blue[500],
+        ),
+      );
+  // #enddocregion list
+}