Add a new Theme widget to control color and text color of apps

sky/examples/widgets/sector.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:math' as math;
 
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/flex.dart';
 import 'package:sky/rendering/sky_binding.dart';
-import 'package:sky/theme/colors.dart';
+import 'package:sky/theme/colors.dart' as colors;
 import 'package:sky/theme/edges.dart';
-import 'package:sky/theme/typography.dart';
+import 'package:sky/theme/theme_data.dart';
+import 'package:sky/theme/typography.dart' as typography;
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/material.dart';
 import 'package:sky/widgets/raised_button.dart';
 import 'package:sky/widgets/scaffold.dart';
+import 'package:sky/widgets/theme.dart';
 import 'package:sky/widgets/tool_bar.dart';
 import 'package:sky/widgets/widget.dart';
 
 import '../rendering/sector_layout.dart';
 
 RenderBox initCircle() {
   return new RenderBoxToRenderSectorAdapter(
     innerRadius: 25.0,
     child: new RenderSectorRing(padding: 0.0)
   );
@@ skipping 40 matching lines @@
   void updateEnabledState() {
     setState(() {
       var ring = (sectors.child as RenderSectorRing);
       SectorDimensions currentSize = ring.getIntrinsicDimensions(const SectorConstraints(), ring.deltaRadius);
       enabledAdd = currentSize.deltaTheta < kTwoPi;
       enabledRemove = ring.firstChild != null;
     });
   }
 
   Widget build() {
-    return new Scaffold(
-      toolbar: new ToolBar(
-          center: new Text('Sector Layout in a Widget Tree', style: white.title),
-          backgroundColor: Blue[500]),
-      body: new Material(
-        edge: MaterialEdge.canvas,
-        child: new Flex([
-            new Container(
-              padding: new EdgeDims.symmetric(horizontal: 8.0, vertical: 25.0),
-              child: new Flex([
-                  new RaisedButton(
-                    enabled: enabledAdd,
-                    child: new ShrinkWrapWidth(
-                      child: new Flex([
-                        new Container(
-                          padding: new EdgeDims.all(4.0),
-                          margin: new EdgeDims.only(right: 10.0),
-                          child: new WidgetToRenderBoxAdapter(sectorAddIcon)
-                        ),
-                        new Text('ADD SECTOR'),
-                      ])
+    return new Theme(
+      data: new ThemeData(color: colors.Blue, text: typography.white),
+      child: new Scaffold(
+        toolbar: new ToolBar(
+            center: new Text('Sector Layout in a Widget Tree', style: typography.white.title)),
+        body: new Material(
+          edge: MaterialEdge.canvas,
+          child: new Flex([
+              new Container(
+                padding: new EdgeDims.symmetric(horizontal: 8.0, vertical: 25.0),
+                child: new Flex([
+                    new RaisedButton(
+                      enabled: enabledAdd,
+                      child: new ShrinkWrapWidth(
+                        child: new Flex([
+                          new Container(
+                            padding: new EdgeDims.all(4.0),
+                            margin: new EdgeDims.only(right: 10.0),
+                            child: new WidgetToRenderBoxAdapter(sectorAddIcon)
+                          ),
+                          new Text('ADD SECTOR'),
+                        ])
+                      ),
+                      onPressed: addSector
                     ),
-                    onPressed: addSector
+                    new RaisedButton(
+                      enabled: enabledRemove,
+                      child: new ShrinkWrapWidth(
+                        child: new Flex([
+                          new Container(
+                            padding: new EdgeDims.all(4.0),
+                            margin: new EdgeDims.only(right: 10.0),
+                            child: new WidgetToRenderBoxAdapter(sectorRemoveIcon)
+                          ),
+                          new Text('REMOVE SECTOR'),
+                        ])
+                      ),
+                      onPressed: removeSector
+                    )
+                  ],
+                  justifyContent: FlexJustifyContent.spaceAround
+                )
+              ),
+              new Flexible(
+                child: new Container(
+                  margin: new EdgeDims.all(8.0),
+                  decoration: new BoxDecoration(
+                    border: new Border.all(new BorderSide(color: new Color(0xFF000000)))
                   ),
-                  new RaisedButton(
-                    enabled: enabledRemove,
-                    child: new ShrinkWrapWidth(
-                      child: new Flex([
-                        new Container(
-                          padding: new EdgeDims.all(4.0),
-                          margin: new EdgeDims.only(right: 10.0),
-                          child: new WidgetToRenderBoxAdapter(sectorRemoveIcon)
-                        ),
-                        new Text('REMOVE SECTOR'),
-                      ])
-                    ),
-                    onPressed: removeSector
-                  )
-                ],
-                justifyContent: FlexJustifyContent.spaceAround
-              )
-            ),
-            new Flexible(
-              child: new Container(
-                margin: new EdgeDims.all(8.0),
-                decoration: new BoxDecoration(
-                  border: new Border.all(new BorderSide(color: new Color(0xFF000000)))
-                ),
-                padding: new EdgeDims.all(8.0),
-                child: new WidgetToRenderBoxAdapter(sectors)
-              )
-            ),
-          ],
-          direction: FlexDirection.vertical,
-          justifyContent: FlexJustifyContent.spaceBetween
+                  padding: new EdgeDims.all(8.0),
+                  child: new WidgetToRenderBoxAdapter(sectors)
+                )
+              ),
+            ],
+            direction: FlexDirection.vertical,
+            justifyContent: FlexJustifyContent.spaceBetween
+          )
         )
       )
     );
   }
 }
 
 void main() {
   runApp(new SectorApp());
   SkyBinding.instance.onFrame = () {
     // uncomment this for debugging:
     // SkyBinding.instance.debugDumpRenderTree();
   };
 }