updated: using_listview example with working implementation

using_listview/lib/main.dart

@@ -1,19 +1,13 @@
 import 'package:flutter/material.dart';
+import 'package:using_listview/contact_page.dart';
 
-void main() => runApp(new MyApp());
-
-class MyApp extends StatelessWidget {
-  // This widget is the root of your application.
-  @override
-  Widget build(BuildContext context) {
-    return new MaterialApp(
-        home: new Scaffold(
+void main() {
+  runApp(new MaterialApp(
+    home: new Scaffold(
       appBar: new AppBar(
         title: new Text("Using Listview"),
       ),
-      body: new Center(
-        child: new Text("Hello World!"),
-      ),
-    ));
-  }
+      body: new ContactPage(),
+    ),
+  ));
 }