updated: using_theme example

using_theme/lib/main.dart

@@ -2,28 +2,51 @@ import 'package:flutter/material.dart';
 
 void main() {
   runApp(new MaterialApp(
-    home: new Scaffold(
+    debugShowCheckedModeBanner: false,
+    home: new MyHome(),
+    // Set the theme's primary color, accent color,
+    theme: new ThemeData(
+      primarySwatch: Colors.green,
+      accentColor: Colors.lightGreenAccent,
+      // Set background color
+      backgroundColor: Colors.black12,
+    ),
+  ));
+}
+
+class MyHome extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return new Scaffold(
       // AppBar
       appBar: new AppBar(
         // AppBar Title
         title: new Text("Using Theme"),
       ),
       body: new Container(
-          child: new Center(
+        // Another way to set the background color
+        decoration: new BoxDecoration(color: Colors.black87),
+        child: new Center(
+          child: new Container(
+            // use the theme accent color as background color for this widget
+            color: Theme.of(context).accentColor,
             child: new Text(
-              "Hello World!",
-              // Set the text style, text color to white
-              style: new TextStyle(color: Colors.white),
+              'Hello World!',
+              // Set text style as per theme
+              style: Theme.of(context).textTheme.title,
             ),
           ),
-          // Another way to set the background color
-          decoration: new BoxDecoration(color: Colors.lightBlueAccent)),
-    ),
-    // Set the theme's primary color, accent color,
-    theme: new ThemeData(
-      primarySwatch: Colors.blue,
-      accentColor: Colors.lightBlueAccent,
-      backgroundColor: Colors.blueAccent,
-    ),
-  ));
+        ),
+      ),
+
+      floatingActionButton: new Theme(
+        // override the accent color of theme for this widget only
+        data: Theme.of(context).copyWith(accentColor: Colors.pinkAccent),
+        child: new FloatingActionButton(
+          onPressed: null,
+          child: new Icon(Icons.add),
+        ),
+      ),
+    );
+  }
 }