Make a variety of private State members actually private.

examples/material_gallery/lib/demo/buttons_demo.dart

@@ -63,12 +63,12 @@ class ButtonsDemo extends StatefulWidget {
 }
 
 class _ButtonsDemoState extends State<ButtonsDemo> {
-  List<_ButtonDemo> demos;
+  List<_ButtonDemo> _demos;
 
   @override
   void initState() {
     super.initState();
-    demos = <_ButtonDemo>[
+    _demos = <_ButtonDemo>[
       new _ButtonDemo(title: 'FLOATING', text: _floatingText, builder: buildFloatingButton),
       new _ButtonDemo(title: 'RAISED', text: _raisedText, builder: buildRaisedButton),
       new _ButtonDemo(title: 'FLAT', text: _flatText, builder: buildFlatButton),
@@ -198,17 +198,17 @@ class _ButtonsDemoState extends State<ButtonsDemo> {
   @override
   Widget build(BuildContext context) {
     return new TabBarSelection<_ButtonDemo>(
-      values: demos,
+      values: _demos,
       child: new Scaffold(
         appBar: new AppBar(
           title: new Text("Buttons"),
           tabBar: new TabBar<_ButtonDemo>(
             isScrollable: true,
-            labels: new Map<_ButtonDemo, TabLabel>.fromIterable(demos, value: (_ButtonDemo demo) => demo.tabLabel)
+            labels: new Map<_ButtonDemo, TabLabel>.fromIterable(_demos, value: (_ButtonDemo demo) => demo.tabLabel)
           )
         ),
         body: new TabBarView<_ButtonDemo>(
-          children: demos.map(buildTabView).toList()
+          children: _demos.map(buildTabView).toList()
         )
       )
     );

examples/material_gallery/lib/demo/dialog_demo.dart

@@ -60,7 +60,7 @@ class DialogDemo extends StatefulWidget {
 }
 
 class DialogDemoState extends State<DialogDemo> {
-  final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>();
+  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
 
   void showDemoDialog/*<T>*/({ BuildContext context, Dialog dialog }) {
     showDialog/*<T>*/(
@@ -69,7 +69,7 @@ class DialogDemoState extends State<DialogDemo> {
     )
     .then((dynamic/*=T*/ value) { // The value passed to Navigator.pop() or null.
       if (value != null) {
-        scaffoldKey.currentState.showSnackBar(new SnackBar(
+        _scaffoldKey.currentState.showSnackBar(new SnackBar(
           content: new Text('You selected: $value')
         ));
       }
@@ -82,7 +82,7 @@ class DialogDemoState extends State<DialogDemo> {
     final TextStyle dialogTextStyle = theme.textTheme.subhead.copyWith(color: theme.textTheme.caption.color);
 
     return new Scaffold(
-      key: scaffoldKey,
+      key: _scaffoldKey,
       appBar: new AppBar(
         title: new Text('Dialogs')
       ),
@@ -179,7 +179,7 @@ class DialogDemoState extends State<DialogDemo> {
               )
               .then((TimeOfDay value) { // The value passed to Navigator.pop() or null.
                 if (value != null) {
-                  scaffoldKey.currentState.showSnackBar(new SnackBar(
+                  _scaffoldKey.currentState.showSnackBar(new SnackBar(
                     content: new Text('You selected: $value')
                   ));
                 }

examples/material_gallery/lib/demo/drop_down_demo.dart

@@ -10,7 +10,7 @@ class DropDownDemo extends StatefulWidget {
 }
 
 class _DropDownDemoState extends State<DropDownDemo> {
-  String value = "Free";
+  String _value = "Free";
 
   List<DropDownMenuItem<String>> buildItems() {
     return <String>["One", "Two", "Free", "Four"].map((String value) {
@@ -26,11 +26,11 @@ class _DropDownDemoState extends State<DropDownDemo> {
       body: new Center(
         child: new DropDownButton<String>(
           items: buildItems(),
-          value: value,
+          value: _value,
           onChanged: (String newValue) {
             setState(() {
               if (newValue != null)
-                value = newValue;
+                _value = newValue;
             });
           }
         )

examples/material_gallery/lib/demo/fitness_demo.dart

@@ -53,16 +53,16 @@ class _FitnessDemoContentsState extends State<_FitnessDemoContents> {
     AssetBundle bundle = DefaultAssetBundle.of(context);
     _loadAssets(bundle).then((_) {
       setState(() {
-        assetsLoaded = true;
+        _assetsLoaded = true;
         workoutAnimation = new _WorkoutAnimationNode(
           onPerformedJumpingJack: () {
             setState(() {
-              count += 1;
+              _count += 1;
             });
           },
           onSecondPassed: (int seconds) {
             setState(() {
-              time = seconds;
+              _time = seconds;
             });
           }
         );
@@ -70,16 +70,16 @@ class _FitnessDemoContentsState extends State<_FitnessDemoContents> {
     });
   }
 
-  bool assetsLoaded = false;
-  int count = 0;
-  int time = 0;
-  int get kcal => (count * 0.2).toInt();
+  bool _assetsLoaded = false;
+  int _count = 0;
+  int _time = 0;
+  int get kcal => (_count * 0.2).toInt();
 
   _WorkoutAnimationNode workoutAnimation;
 
   @override
   Widget build(BuildContext context) {
-    if (!assetsLoaded)
+    if (!_assetsLoaded)
       return new Container();
 
     Color buttonColor;
@@ -115,8 +115,8 @@ class _FitnessDemoContentsState extends State<_FitnessDemoContents> {
             child: new Row(
               mainAxisAlignment: MainAxisAlignment.center,
               children: <Widget>[
-                _createInfoPanelCell(Icons.accessibility, '$count', 'COUNT'),
-                _createInfoPanelCell(Icons.timer, _formatSeconds(time), 'TIME'),
+                _createInfoPanelCell(Icons.accessibility, '$_count', 'COUNT'),
+                _createInfoPanelCell(Icons.timer, _formatSeconds(_time), 'TIME'),
                 _createInfoPanelCell(Icons.flash_on, '$kcal', 'KCAL')
               ]
             )
@@ -170,8 +170,8 @@ class _FitnessDemoContentsState extends State<_FitnessDemoContents> {
 
   void startWorkout() {
     setState(() {
-      count = 0;
-      time = 0;
+      _count = 0;
+      _time = 0;
       workoutAnimation.start();
     });
   }
@@ -180,14 +180,14 @@ class _FitnessDemoContentsState extends State<_FitnessDemoContents> {
     setState(() {
       workoutAnimation.stop();
 
-      if (count >= 3) {
+      if (_count >= 3) {
         showDialog(
           context: context,
           child: new Stack(children: <Widget>[
             new _Fireworks(),
             new Dialog(
               title: new Text("Awesome workout"),
-              content: new Text("You have completed $count jumping jacks. Good going!"),
+              content: new Text("You have completed $_count jumping jacks. Good going!"),
               actions: <Widget>[
                 new FlatButton(
                   child: new Text("SWEET"),

examples/material_gallery/lib/demo/flexible_space_demo.dart

@@ -75,9 +75,9 @@ class FlexibleSpaceDemo extends StatefulWidget {
 }
 
 class FlexibleSpaceDemoState extends State<FlexibleSpaceDemo> {
-  final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>();
-  final double appBarHeight = 256.0;
-  final Key scrollableKey = new UniqueKey();
+  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
+  final double _appBarHeight = 256.0;
+  final Key _scrollableKey = new UniqueKey();
   AppBarBehavior _appBarBehavior = AppBarBehavior.scroll;
 
   @override
@@ -89,17 +89,17 @@ class FlexibleSpaceDemoState extends State<FlexibleSpaceDemo> {
         primarySwatch: Colors.indigo
       ),
       child: new Scaffold(
-        key: scaffoldKey,
-        scrollableKey: scrollableKey,
+        key: _scaffoldKey,
+        scrollableKey: _scrollableKey,
         appBarBehavior: _appBarBehavior,
         appBar: new AppBar(
-          expandedHeight: appBarHeight,
+          expandedHeight: _appBarHeight,
           actions: <Widget>[
             new IconButton(
               icon: Icons.create,
               tooltip: 'Search',
               onPressed: () {
-                scaffoldKey.currentState.showSnackBar(new SnackBar(
+                _scaffoldKey.currentState.showSnackBar(new SnackBar(
                   content: new Text('Not supported.')
                 ));
               }
@@ -128,14 +128,14 @@ class FlexibleSpaceDemoState extends State<FlexibleSpaceDemo> {
               image: new AssetImage(
                 name: 'packages/flutter_gallery_assets/ali_connors.png',
                 fit: ImageFit.cover,
-                height: appBarHeight
+                height: _appBarHeight
               )
             );
           }
         ),
         body: new Block(
-          scrollableKey: scrollableKey,
-          padding: new EdgeInsets.only(top: appBarHeight + statusBarHeight),
+          scrollableKey: _scrollableKey,
+          padding: new EdgeInsets.only(top: _appBarHeight + statusBarHeight),
           children: <Widget>[
             new _ContactCategory(
               icon: Icons.call,

examples/material_gallery/lib/demo/full_screen_dialog_demo.dart

@@ -99,13 +99,13 @@ class FullScreenDialogDemo extends StatefulWidget {
 }
 
 class FullScreenDialogDemoState extends State<FullScreenDialogDemo> {
-  DateTime fromDateTime = new DateTime.now();
-  DateTime toDateTime = new DateTime.now();
-  bool allDayValue = false;
-  bool saveNeeded = false;
+  DateTime _fromDateTime = new DateTime.now();
+  DateTime _toDateTime = new DateTime.now();
+  bool _allDayValue = false;
+  bool _saveNeeded = false;
 
   void handleDismissButton(BuildContext context) {
-    if (!saveNeeded) {
+    if (!_saveNeeded) {
       Navigator.pop(context, null);
       return;
     }
@@ -192,11 +192,11 @@ class FullScreenDialogDemoState extends State<FullScreenDialogDemo> {
                 children: <Widget>[
                   new Text('From', style: theme.textTheme.caption),
                   new DateTimeItem(
-                    dateTime: fromDateTime,
+                    dateTime: _fromDateTime,
                     onChanged: (DateTime value) {
                       setState(() {
-                        fromDateTime = value;
-                        saveNeeded = true;
+                        _fromDateTime = value;
+                        _saveNeeded = true;
                       });
                     }
                   )
@@ -208,11 +208,11 @@ class FullScreenDialogDemoState extends State<FullScreenDialogDemo> {
                 children: <Widget>[
                   new Text('To', style: theme.textTheme.caption),
                   new DateTimeItem(
-                    dateTime: toDateTime,
+                    dateTime: _toDateTime,
                     onChanged: (DateTime value) {
                       setState(() {
-                        toDateTime = value;
-                        saveNeeded = true;
+                        _toDateTime = value;
+                        _saveNeeded = true;
                       });
                     }
                   )
@@ -225,11 +225,11 @@ class FullScreenDialogDemoState extends State<FullScreenDialogDemo> {
                 child: new Row(
                   children: <Widget> [
                     new Checkbox(
-                      value: allDayValue,
+                      value: _allDayValue,
                       onChanged: (bool value) {
                         setState(() {
-                          allDayValue = value;
-                          saveNeeded = true;
+                          _allDayValue = value;
+                          _saveNeeded = true;
                         });
                       }
                     ),