Delete drawerController and make drawer handle back behavior natively

sky/sdk/example/fitness/lib/home.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 'package:sky/painting/text_style.dart';
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/drawer.dart';
 import 'package:sky/widgets/drawer_divider.dart';
 import 'package:sky/widgets/drawer_header.dart';
 import 'package:sky/widgets/drawer_item.dart';
@@ skipping 16 matching lines @@
   HomeFragment(this.navigator, this.userData);
 
   Navigator navigator;
   List<Measurement> userData;
 
   FitnessMode _fitnessMode = FitnessMode.measure;
 
   void initState() {
     // if (debug)
     //   new Timer(new Duration(seconds: 1), dumpState);
-    _drawerController = new DrawerController(_handleDrawerStatusChanged);
     super.initState();
   }
 
   void syncFields(HomeFragment source) {
     navigator = source.navigator;
     userData = source.userData;
   }
 
   bool _isShowingSnackBar = false;
   bool _isRunning = false;
 
-  DrawerController _drawerController;
-  bool _drawerShowing = false;
-
-  void _handleDrawerStatusChanged(bool showing) {
-    if (!showing && navigator.currentRoute.name == "/drawer") {
-      navigator.pop();
-    }
-    setState(() {
-      _drawerShowing = showing;
-    });
-  }
-
   void _handleFitnessModeChange(FitnessMode value) {
     setState(() {
       _fitnessMode = value;
     });
-    assert(navigator.currentRoute.name == '/drawer');
-    navigator.pop();
   }
 
   Drawer buildDrawer() {
+    if (_drawerStatus == DrawerStatus.inactive)
+      return null;
     return new Drawer(
-      controller: _drawerController,
+      showing: _drawerShowing,
       level: 3,
+      onStatusChanged: _handleDrawerStatusChange,
+      navigator: navigator,
       children: [
         new DrawerHeader(children: [new Text('Fitness')]),
         new DrawerItem(
           icon: 'action/assessment',
           onPressed: () => _handleFitnessModeChange(FitnessMode.measure),
           selected: _fitnessMode == FitnessMode.measure,
           children: [new Text('Measure')]),
         new DrawerItem(
           icon: 'maps/directions_run',
           onPressed: () => _handleFitnessModeChange(FitnessMode.run),
           selected: _fitnessMode == FitnessMode.run,
           children: [new Text('Run')]),
         new DrawerDivider(),
         new DrawerItem(
           icon: 'action/settings',
           onPressed: _handleShowSettings,
           children: [new Text('Settings')]),
         new DrawerItem(
           icon: 'action/help',
           children: [new Text('Help & Feedback')])
      ]
     );
   }
 
-  void _handleShowSettings() {
-    assert(navigator.currentRoute.name == '/drawer');
-    navigator.pop();
-    assert(navigator.currentRoute.name == '/');
-    navigator.pushNamed('/settings');
+  bool _drawerShowing = false;
+  DrawerStatus _drawerStatus = DrawerStatus.inactive;
+
+  void _handleOpenDrawer() {
+    setState(() {
+      _drawerShowing = true;
+      _drawerStatus = DrawerStatus.active;
+    });
   }
 
-  void _handleOpenDrawer() {
-    _drawerController.open();
-    navigator.pushState("/drawer", (_) {
-      _drawerController.close();
+  void _handleDrawerStatusChange(DrawerStatus status) {
+    if (status == DrawerStatus.inactive && navigator.currentRoute.name == "/drawer") {
+      navigator.pop();
+    }
+    setState(() {
+      _drawerStatus = status;
     });
   }
 
+  void _handleShowSettings() {
+    navigator.pop();
+    navigator.pushNamed('/settings');
+  }
+
   // TODO(jackson): We should be localizing
   String get fitnessModeTitle {
     switch(_fitnessMode) {
       case FitnessMode.measure: return "Measure";
       case FitnessMode.run: return "Run";
     }
   }
 
   Widget buildToolBar() {
     return new ToolBar(
@@ skipping 75 matching lines @@
         );
     }
   }
 
   Widget build() {
     return new Scaffold(
       toolbar: buildToolBar(),
       body: buildBody(),
       snackBar: buildSnackBar(),
       floatingActionButton: buildFloatingActionButton(),
-      drawer: _drawerShowing ? buildDrawer() : null
+      drawer: buildDrawer()
     );
   }
 }