list view,

title change,
nested listing

Author: ibhavikmakwana

lib/main.dart

@@ -11,8 +11,8 @@ import 'package:flutter_examples/ui/collapsibletoolbar/CollapsibleToolbar.dart';
 import 'package:flutter_examples/ui/dragdrop/ExampleDragDrop.dart';
 import 'package:flutter_examples/ui/drawer/NavigationDrawer.dart';
 import 'package:flutter_examples/ui/hardwarekey/RawKeyboardDemo.dart';
-import 'package:flutter_examples/ui/lifecycle/Lifecycle.dart';
 import 'package:flutter_examples/ui/local_auth/LocalAuth.dart';
+import 'package:flutter_examples/ui/nestedlist/NestedListExample.dart';
 import 'package:flutter_examples/ui/progressbutton/ProgressButton.dart';
 import 'package:flutter_examples/ui/staggeredanimation/StaggerDemo.dart';
 import 'package:flutter_examples/ui/stepper/StepperExample.dart';
@@ -37,8 +37,7 @@ class MyApp extends StatelessWidget {
         home: new MyHomePage(title: Strings.appName),
         routes: <String, WidgetBuilder>{
           Strings.appBarExampleRoute: (BuildContext context) => AppBarExample(),
-          Strings.tabBarExampleRoute: (BuildContext context) =>
-              TabBarExample(
+          Strings.tabBarExampleRoute: (BuildContext context) => TabBarExample(
                 title: Strings.TabBarTitle,
               ),
           Strings.navigationDrawerExampleRoute: (BuildContext context) =>
@@ -73,7 +72,7 @@ class MyApp extends StatelessWidget {
           Strings.aboutListTileExampleRoute: (BuildContext context) =>
               AboutListTileExample(title: Strings.aboutListTileExampleTitle),
           Strings.lifeCycleStateExampleRoute: (BuildContext context) =>
-              Lifecycle(title: Strings.lifeCycleStateExampleTitle),
+              NestedListExample(),
           Strings.localAuthExampleRoute: (BuildContext context) => LocalAuth(),
         });
   }
@@ -148,10 +147,9 @@ class _MyHomePageState extends State<MyHomePage>
   _buildExampleItemsWidget(bool status) {
     if (status) {
       return new ListView.builder(
-        itemBuilder: (BuildContext context, int index) =>
-        new ExampleNameItem(
-          exampleNames: names[index],
-        ),
+        itemBuilder: (BuildContext context, int index) => new ExampleNameItem(
+              exampleNames: names[index],
+            ),
         itemCount: names.length,
       );
     } else {
@@ -160,10 +158,9 @@ class _MyHomePageState extends State<MyHomePage>
           crossAxisCount: 2,
           childAspectRatio: 3.0,
         ),
-        itemBuilder: (BuildContext context, int index) =>
-        new ExampleNameItem(
-          exampleNames: names[index],
-        ),
+        itemBuilder: (BuildContext context, int index) => new ExampleNameItem(
+              exampleNames: names[index],
+            ),
         itemCount: names.length,
       );
     }

lib/ui/local_auth/LocalAuth.dart

@@ -12,6 +12,24 @@ class LocalAuth extends StatefulWidget {
 class _LocalAuthState extends State<LocalAuth> {
   String _authorized = 'Not Authorized';
 
+  Future<Null> _authenticateWithBiometrics() async {
+    final LocalAuthentication auth = new LocalAuthentication();
+    bool authenticated = false;
+    try {
+      authenticated = await auth.authenticateWithBiometrics(
+          localizedReason: 'Scan your fingerprint to authenticate',
+          useErrorDialogs: true,
+          stickyAuth: false);
+    } on PlatformException catch (e) {
+      print(e);
+    }
+    if (!mounted) return;
+
+    setState(() {
+      _authorized = authenticated ? 'Authorized' : 'Not Authorized';
+    });
+  }
+
   Future<Null> _authenticate() async {
     final LocalAuthentication auth = new LocalAuthentication();
     bool authenticated = false;
@@ -35,19 +53,23 @@ class _LocalAuthState extends State<LocalAuth> {
     return new MaterialApp(
         home: new Scaffold(
       appBar: new AppBar(
-        title: const Text('Plugin example app'),
+        title: const Text('Local authentication'),
       ),
       body: new ConstrainedBox(
-          constraints: const BoxConstraints.expand(),
-          child: new Column(
-              mainAxisAlignment: MainAxisAlignment.spaceAround,
-              children: <Widget>[
-                new Text('Current State: $_authorized\n'),
-                new RaisedButton(
-                  child: const Text('Authenticate'),
-                  onPressed: _authenticate,
-                )
-              ])),
+        constraints: const BoxConstraints.expand(),
+        child: ListView(
+          children: <Widget>[
+            new RaisedButton(
+              child: const Text('Authenticate'),
+              onPressed: _authenticateWithBiometrics,
+            ),
+            new RaisedButton(
+              child: const Text('Authenticate'),
+              onPressed: _authenticateWithBiometrics,
+            ),
+          ],
+        ),
+      ),
     ));
   }
 }

lib/ui/nestedlist/NestedListExample.dart

@@ -0,0 +1,101 @@
+import 'package:flutter/material.dart';
+
+// The base class for the different types of items the List can contain
+abstract class ListItem {}
+
+// A ListItem that contains data to display a heading
+class HeadingItem implements ListItem {
+  final String heading;
+
+  HeadingItem(this.heading);
+}
+
+// A ListItem that contains data to display a message
+class MessageItem implements ListItem {
+  final String sender;
+  final String body;
+
+  MessageItem(this.sender, this.body);
+}
+
+class NestedListExample extends StatefulWidget {
+  final items = List<ListItem>.generate(
+    20,
+    (i) => HeadingItem("Heading $i"),
+  );
+
+  @override
+  _NestedListExampleState createState() => _NestedListExampleState();
+}
+
+class _NestedListExampleState extends State<NestedListExample>
+    with SingleTickerProviderStateMixin {
+  TabController _tabController;
+  ScrollController _scrollController;
+  var _globalKey = GlobalKey();
+
+  @override
+  void initState() {
+    _tabController =
+        new TabController(length: widget.items.length, vsync: this);
+    _scrollController = ScrollController();
+    _tabController.addListener(_handleTabSelection);
+    super.initState();
+  }
+
+  @override
+  void dispose() {
+    _scrollController.dispose();
+    _tabController.dispose();
+    super.dispose();
+  }
+
+  void _handleTabSelection() {
+    setState(() {
+      var height = _globalKey.currentContext;
+      final RenderBox box = height.findRenderObject();
+      _scrollController.animateTo(_tabController.offset,
+          curve: Curves.ease, duration: Duration(seconds: 2));
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text("Nested List"),
+        bottom: TabBar(
+          isScrollable: true,
+          tabs: List<Widget>.generate(
+            widget.items.length,
+            (int index) {
+              return new Tab(
+                text: "$index",
+              );
+            },
+          ),
+          controller: _tabController,
+        ),
+      ),
+      body: ListView.builder(
+        controller: _scrollController,
+        // Let the ListView know how many items it needs to build
+        itemCount: widget.items.length,
+        // Provide a builder function. This is where the magic happens! We'll
+        // convert each item into a Widget based on the type of item it is.
+        itemBuilder: (context, index) {
+          final item = widget.items[index];
+          if (item is HeadingItem) {
+            return ListTile(
+              key: _globalKey,
+              title: Text(
+                item.heading,
+                style: Theme.of(context).textTheme.headline,
+              ),
+            );
+          }
+        },
+      ),
+    );
+  }
+}