Updated DrawerHeader and added UserAccountDrawer.

Removed old Stack layout and added a simple-to-extend interface for the
new drawer header. Also added a specialized UserAccountsDrawerHeader
consistent with Material Design guidelines.

dev/manual_tests/card_collection.dart

@@ -126,7 +126,7 @@ class CardCollectionState extends State<CardCollection> {
       child: new IconTheme(
         data: const IconThemeData(color: Colors.black),
         child: new Block(children: <Widget>[
-          new DrawerHeader(content: new Center(child: new Text('Options'))),
+          new DrawerHeader(child: new Center(child: new Text('Options'))),
           buildDrawerCheckbox("Make card labels editable", _editable, _toggleEditable),
           buildDrawerCheckbox("Snap fling scrolls to center", _snapToCenter, _toggleSnapToCenter),
           buildDrawerCheckbox("Fixed size cards", _fixedSizeCards, _toggleFixedSizeCards),

dev/manual_tests/pageable_list.dart

@@ -85,7 +85,7 @@ class PageableListAppState extends State<PageableListApp> {
   Widget _buildDrawer() {
     return new Drawer(
       child: new Block(children: <Widget>[
-        new DrawerHeader(content: new Center(child: new Text('Options'))),
+        new DrawerHeader(child: new Center(child: new Text('Options'))),
         new DrawerItem(
           icon: new Icon(Icons.more_horiz),
           selected: scrollDirection == Axis.horizontal,

examples/flutter_gallery/lib/demo/pesto_demo.dart

@@ -121,7 +121,8 @@ class _PestoDemoState extends State<PestoDemo> {
       child: new Block(
         children: <Widget>[
           new DrawerHeader(
-            content: new Column(
+            child: new Column(
+              mainAxisAlignment: MainAxisAlignment.center,
               children: <Widget>[
                 new Container(
                   decoration: new BoxDecoration(
@@ -131,7 +132,7 @@ class _PestoDemoState extends State<PestoDemo> {
                   width: 72.0,
                   height: 72.0,
                   padding: const EdgeInsets.all(2.0),
-                  margin: const EdgeInsets.only(bottom: 8.0),
+                  margin: const EdgeInsets.only(bottom: 16.0),
                   child: new ClipOval(
                     child: new Image(
                       image: new AssetImage(_kUserImage),

examples/flutter_gallery/lib/gallery/drawer.dart

@@ -49,7 +49,7 @@ class GalleryDrawer extends StatelessWidget {
       child: new Block(
         children: <Widget>[
           new DrawerHeader(
-            content: new Center(child: new Text('Flutter gallery'))
+            child: new Center(child: new Text('Flutter gallery'))
           ),
           new DrawerItem(
             icon: new Icon(Icons.brightness_5),

examples/stocks/lib/stock_home.dart

@@ -124,7 +124,7 @@ class StockHomeState extends State<StockHome> {
   Widget _buildDrawer(BuildContext context) {
     return new Drawer(
       child: new Block(children: <Widget>[
-        new DrawerHeader(content: new Center(child: new Text('Stocks'))),
+        new DrawerHeader(child: new Center(child: new Text('Stocks'))),
         new DrawerItem(
           icon: new Icon(Icons.assessment),
           selected: true,

packages/flutter/lib/material.dart

@@ -72,5 +72,6 @@ export 'src/material/toggleable.dart';
 export 'src/material/tooltip.dart';
 export 'src/material/two_level_list.dart';
 export 'src/material/typography.dart';
+export 'src/material/user_accounts_drawer_header.dart';
 
 export 'widgets.dart';

packages/flutter/lib/src/material/drawer_header.dart

@@ -7,11 +7,11 @@ import 'package:flutter/widgets.dart';
 import 'debug.dart';
 import 'theme.dart';
 
-const double _kDrawerHeaderHeight = 140.0;
+const double _kDrawerHeaderHeight = 160.0 + 1.0; // bottom edge
 
-/// The top-most region of a material design drawer. The header's [background]
-/// widget extends behind the system status bar and its [content] widget is
-/// stacked on top of the background and below the status bar.
+/// The top-most region of a material design drawer. The header's [child]
+/// widget is placed inside of a [Container] whose [decoration] can be passed as
+/// an argument.
 ///
 /// Part of the material design [Drawer].
 ///
@@ -22,19 +22,24 @@ const double _kDrawerHeaderHeight = 140.0;
 ///  * [Drawer]
 ///  * [DrawerItem]
 ///  * <https://www.google.com/design/spec/patterns/navigation-drawer.html>
+
 class DrawerHeader extends StatelessWidget {
   /// Creates a material design drawer header.
   ///
   /// Requires one of its ancestors to be a [Material] widget.
-  const DrawerHeader({ Key key, this.background, this.content }) : super(key: key);
+  const DrawerHeader({
+    Key key,
+    this.decoration,
+    this.child
+  }) : super(key: key);
 
-  /// A widget that extends behind the system status bar and is stacked
-  /// behind the [content] widget.
-  final Widget background;
+  /// Decoration for the main drawer header [Container]; useful for applying
+  /// backgrounds.
+  final BoxDecoration decoration;
 
-  /// A widget that's positioned below the status bar and stacked on top of the
-  /// [background] widget. Typically a view of the user's id.
-  final Widget content;
+  /// A widget that extends behind the system status bar and is placed inside a
+  /// [Container].
+  final Widget child;
 
   @override
   Widget build(BuildContext context) {
@@ -42,7 +47,7 @@ class DrawerHeader extends StatelessWidget {
     final double statusBarHeight = MediaQuery.of(context).padding.top;
     return new Container(
       height: statusBarHeight + _kDrawerHeaderHeight,
-      margin: const EdgeInsets.only(bottom: 7.0), // 8 less 1 for the bottom border.
+      margin: const EdgeInsets.only(bottom: 8.0),
       decoration: new BoxDecoration(
         border: const Border(
           bottom: const BorderSide(
@@ -51,20 +56,18 @@ class DrawerHeader extends StatelessWidget {
           )
         )
       ),
-      child: new Stack(
-        children: <Widget>[
-          background ?? new Container(),
-          new Positioned(
-            top: statusBarHeight + 16.0,
-            left: 16.0,
-            right: 16.0,
-            bottom: 8.0,
-            child: new DefaultTextStyle(
-              style: Theme.of(context).textTheme.body2,
-              child: content
-            )
-          )
-        ]
+      child: new Container(
+        padding: new EdgeInsets.only(
+          top: 16.0 + statusBarHeight,
+          left: 16.0,
+          right: 16.0,
+          bottom: 8.0
+        ),
+        decoration: decoration,
+        child: new DefaultTextStyle(
+          style: Theme.of(context).textTheme.body2,
+          child: child
+        )
       )
     );
   }

packages/flutter/lib/src/material/user_accounts_drawer_header.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:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+
+import 'debug.dart';
+
+/// A material design [Drawer] header that identifies the app's user.
+///
+/// The top-most region of a material design drawer with user accounts. The
+/// header's [decoration] is used to provide a background.
+/// [currentAccountPicture] is the main account picture on the left, while
+/// [otherAccountsPictures] are the smaller account pictures on the right.
+/// [accountName] and [accountEmail] provide access to the top and bottom rows
+/// of the account details in the lower part of the header. When touched, this
+/// area triggers [onDetailsPressed] and toggles the dropdown icon on the right.
+///
+/// Requires one of its ancestors to be a [Material] widget.
+///
+/// See also:
+///
+///  * [Drawer]
+///  * [DrawerItem]
+///  * <https://www.google.com/design/spec/patterns/navigation-drawer.html>
+
+class UserAccountsDrawerHeader extends StatefulWidget {
+  /// Creates a material design drawer header.
+  ///
+  /// Requires one of its ancestors to be a [Material] widget.
+  UserAccountsDrawerHeader({
+    Key key,
+    this.decoration,
+    this.currentAccountPicture,
+    this.otherAccountsPictures,
+    this.accountName,
+    this.accountEmail,
+    this.onDetailsPressed
+  }) : super(key: key);
+
+  /// A callback that gets called when the account name/email/dropdown
+  /// section is pressed.
+  final VoidCallback onDetailsPressed;
+
+  /// Decoration for the main drawer header container useful for applying
+  /// backgrounds.
+  final BoxDecoration decoration;
+
+  /// A widget placed in the upper-left corner representing the current
+  /// account picture. Normally a [CircleAvatar].
+  final Widget currentAccountPicture;
+
+  /// A list of widgets that represent the user's accounts. Up to three of them
+  /// are arranged in a row in the header's upper-right corner. Normally a list
+  /// of [CircleAvatar] widgets.
+  final List<Widget> otherAccountsPictures;
+
+  /// A widget placed on the top row of the account details representing
+  /// account name.
+  final Widget accountName;
+
+  /// A widget placed on the bottom row of the account details representing
+  /// account email.
+  final Widget accountEmail;
+
+  @override
+  _UserAccountsDrawerHeaderState createState() =>
+      new _UserAccountsDrawerHeaderState();
+}
+
+class _UserAccountsDrawerHeaderState extends State<UserAccountsDrawerHeader> {
+  /// Saves whether the account dropdown is open or not.
+  bool isOpen = false;
+
+  @override
+  Widget build(BuildContext context) {
+    assert(debugCheckHasMaterial(context));
+    final List<Widget> otherAccountsPictures = config.otherAccountsPictures ??
+        <Widget>[];
+    return new DrawerHeader(
+      decoration: config.decoration,
+      child: new Column(
+        children: <Widget>[
+          new Flexible(
+            child: new Stack(
+              children: <Widget>[
+                new Positioned(
+                  top: 0.0,
+                  right: 0.0,
+                  child: new Row(
+                    children: otherAccountsPictures.take(3).map(
+                      (Widget picture) {
+                        return new Container(
+                          margin: const EdgeInsets.only(left: 16.0),
+                          width: 40.0,
+                          height: 40.0,
+                          child: picture
+                        );
+                      }
+                    ).toList()
+                  )
+                ),
+                new Positioned(
+                  top: 0.0,
+                  child: new Container(
+                    width: 72.0,
+                    height: 72.0,
+                    child: config.currentAccountPicture
+                  )
+                )
+              ]
+            )
+          ),
+          new Container(
+            height: 56.0,
+            child: new InkWell(
+              onTap: () {
+                setState(() {
+                  isOpen = !isOpen;
+                });
+                if (config.onDetailsPressed != null)
+                  config.onDetailsPressed();
+              },
+              child: new Container(
+                margin: const EdgeInsets.symmetric(vertical: 8.0),
+                child: new Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+                  children: <Widget>[
+                    new DefaultTextStyle(
+                      style: const TextStyle(
+                        fontWeight: FontWeight.w500,
+                        color: Colors.white
+                      ),
+                      child: config.accountName
+                    ),
+                    new Row(
+                      crossAxisAlignment: CrossAxisAlignment.center,
+                      children: <Widget>[
+                        new DefaultTextStyle(
+                          style: const TextStyle(color: Colors.white),
+                          child: config.accountEmail
+                        ),
+                        new Flexible(
+                          child: new Align(
+                            alignment: FractionalOffset.centerRight,
+                            child: new Icon(
+                              isOpen ? Icons.arrow_drop_up :
+                                  Icons.arrow_drop_down,
+                              color: Colors.white
+                            )
+                          )
+                        )
+                      ]
+                    )
+                  ]
+                )
+              )
+            )
+          )
+        ]
+      )
+    );
+  }
+}

packages/flutter/test/material/drawer_test.dart

@@ -7,13 +7,18 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   testWidgets('Drawer control test', (WidgetTester tester) async {
+    final Key containerKey = new Key('container');
+
     await tester.pumpWidget(
       new Scaffold(
         drawer: new Drawer(
           child: new Block(
             children: <Widget>[
               new DrawerHeader(
-                content: new Text('header')
+                child: new Container(
+                  key: containerKey,
+                  child: new Text('header')
+                )
               ),
               new DrawerItem(
                 icon: new Icon(Icons.archive),
@@ -28,8 +33,21 @@ void main() {
     expect(find.text('Archive'), findsNothing);
     ScaffoldState state = tester.firstState(find.byType(Scaffold));
     state.openDrawer();
+
     await tester.pump();
     await tester.pump(const Duration(seconds: 1));
     expect(find.text('Archive'), findsOneWidget);
+
+    RenderBox box = tester.renderObject(find.byType(DrawerHeader));
+    expect(box.size.height, equals(160.0 + 8.0 + 1.0)); // height + bottom margin + bottom edge
+
+    final double drawerWidth = box.size.width;
+    final double drawerHeight = box.size.height;
+
+    box = tester.renderObject(find.byKey(containerKey));
+    expect(box.size.width, equals(drawerWidth - 2 * 16.0));
+    expect(box.size.height, equals(drawerHeight - 2 * 16.0 - 1.0)); // bottom edge
+
+    expect(find.text('header'), findsOneWidget);
   });
 }

packages/flutter/test/material/user_accounts_drawer_header_test.dart

+// Copyright 2016 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:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('UserAccuntsDrawerHeader test', (WidgetTester tester) async {
+    final Key avatarA = new Key('A');
+    final Key avatarC = new Key('C');
+    final Key avatarD = new Key('D');
+
+    await tester.pumpWidget(
+      new Material(
+        child: new UserAccountsDrawerHeader(
+          currentAccountPicture: new CircleAvatar(
+            key: avatarA,
+            child: new Text('A')
+          ),
+          otherAccountsPictures: <Widget>[
+            new CircleAvatar(
+              child: new Text('B')
+            ),
+            new CircleAvatar(
+              key: avatarC,
+              child: new Text('C')
+            ),
+            new CircleAvatar(
+              key: avatarD,
+              child: new Text('D')
+            ),
+            new CircleAvatar(
+              child: new Text('E')
+            )
+          ],
+          accountName: new Text("name"),
+          accountEmail: new Text("email")
+        )
+      )
+    );
+
+    expect(find.text('A'), findsOneWidget);
+    expect(find.text('B'), findsOneWidget);
+    expect(find.text('C'), findsOneWidget);
+    expect(find.text('D'), findsOneWidget);
+    expect(find.text('E'), findsNothing);
+
+    expect(find.text('name'), findsOneWidget);
+    expect(find.text('email'), findsOneWidget);
+
+    RenderBox box = tester.renderObject(find.byKey(avatarA));
+    expect(box.size.width, equals(72.0));
+    expect(box.size.height, equals(72.0));
+
+    box = tester.renderObject(find.byKey(avatarC));
+    expect(box.size.width, equals(40.0));
+    expect(box.size.height, equals(40.0));
+
+    Point topLeft = tester.getTopLeft(find.byType(UserAccountsDrawerHeader));
+    Point topRight = tester.getTopRight(find.byType(UserAccountsDrawerHeader));
+
+    Point avatarATopLeft = tester.getTopLeft(find.byKey(avatarA));
+    Point avatarDTopRight = tester.getTopRight(find.byKey(avatarD));
+    Point avatarCTopRight = tester.getTopRight(find.byKey(avatarC));
+
+    expect(avatarATopLeft.x - topLeft.x, equals(16.0));
+    expect(avatarATopLeft.y - topLeft.y, equals(16.0));
+    expect(topRight.x - avatarDTopRight.x, equals(16.0));
+    expect(avatarDTopRight.y - topRight.y, equals(16.0));
+    expect(avatarDTopRight.x - avatarCTopRight.x, equals(40.0 + 16.0)); // size + space between
+  });
+}