Added menu dividers

examples/material_gallery/lib/demo/menu_demo.dart

@@ -111,7 +111,7 @@ class MenuDemoState extends State<MenuDemo> {
             primary: new Text('An item with a sectioned menu'),
             right: new PopupMenuButton<String>(
               onSelected: showMenuSelection,
-              items: <PopupMenuItem>[
+              items: <PopupMenuEntry<String>>[
                 new PopupMenuItem(
                   value: 'Preview',
                   child: new ListItem(
@@ -128,12 +128,12 @@ class MenuDemoState extends State<MenuDemo> {
                 ),
                 new PopupMenuItem(
                   value: 'Get Link',
-                  hasDivider: true,
                   child: new ListItem(
                     left: new Icon(icon: 'content/link'),
                     primary: new Text('Get Link')
                   )
                 ),
+                new PopupMenuDivider(),
                 new PopupMenuItem(
                   value: 'Remove',
                   child: new ListItem(

examples/material_gallery/lib/gallery/drawer.dart

@@ -56,7 +56,7 @@ class GalleryDrawer extends StatelessComponent {
               ]
             )
           ),
-          new DrawerDivider(),
+          new Divider(),
           new DrawerItem(
             icon: 'action/hourglass_empty',
             selected: timeDilation != 1.0,

examples/stocks/lib/stock_home.dart

@@ -169,7 +169,7 @@ class StockHomeState extends State<StockHome> {
           },
           child: new Text('Dump App to Console')
         ),
-        new DrawerDivider(),
+        new Divider(),
         new DrawerItem(
           icon: 'action/thumb_up',
           onPressed: () => _handleStockModeChange(StockMode.optimistic),
@@ -190,7 +190,7 @@ class StockHomeState extends State<StockHome> {
             ]
           )
         ),
-        new DrawerDivider(),
+        new Divider(),
         new DrawerItem(
           icon: 'action/settings',
           onPressed: _handleShowSettings,

examples/widgets/card_collection.dart

@@ -128,20 +128,20 @@ class CardCollectionState extends State<CardCollection> {
           buildDrawerCheckbox("Fixed size cards", _fixedSizeCards, _toggleFixedSizeCards),
           buildDrawerCheckbox("Let the sun shine", _sunshine, _toggleSunshine),
           buildDrawerCheckbox("Vary font sizes", _varyFontSizes, _toggleVaryFontSizes, enabled: !_editable),
-          new DrawerDivider(),
+          new Divider(),
           buildDrawerColorRadioItem("Deep Purple", Colors.deepPurple, _primaryColor, _selectColor),
           buildDrawerColorRadioItem("Green", Colors.green, _primaryColor, _selectColor),
           buildDrawerColorRadioItem("Amber", Colors.amber, _primaryColor, _selectColor),
           buildDrawerColorRadioItem("Teal", Colors.teal, _primaryColor, _selectColor),
-          new DrawerDivider(),
+          new Divider(),
           buildDrawerDirectionRadioItem("Dismiss horizontally", DismissDirection.horizontal, _dismissDirection, _changeDismissDirection, icon: 'action/code'),
           buildDrawerDirectionRadioItem("Dismiss left", DismissDirection.left, _dismissDirection, _changeDismissDirection, icon: 'navigation/arrow_back'),
           buildDrawerDirectionRadioItem("Dismiss right", DismissDirection.right, _dismissDirection, _changeDismissDirection, icon: 'navigation/arrow_forward'),
-          new DrawerDivider(),
+          new Divider(),
           buildFontRadioItem("Left-align text", new TextStyle(textAlign: TextAlign.left), _textStyle, _changeTextStyle, icon: 'editor/format_align_left', enabled: !_editable),
           buildFontRadioItem("Center-align text", new TextStyle(textAlign: TextAlign.center), _textStyle, _changeTextStyle, icon: 'editor/format_align_center', enabled: !_editable),
           buildFontRadioItem("Right-align text", new TextStyle(textAlign: TextAlign.right), _textStyle, _changeTextStyle, icon: 'editor/format_align_right', enabled: !_editable),
-          new DrawerDivider(),
+          new Divider(),
           new DrawerItem(
             icon: 'device/dvr',
             onPressed: () { debugDumpApp(); debugDumpRenderTree(); },

packages/flutter/lib/material.dart

@@ -20,9 +20,9 @@ export 'src/material/date_picker.dart';
 export 'src/material/date_picker_dialog.dart';
 export 'src/material/dialog.dart';
 export 'src/material/drawer.dart';
-export 'src/material/drawer_divider.dart';
 export 'src/material/drawer_header.dart';
 export 'src/material/drawer_item.dart';
+export 'src/material/divider.dart';
 export 'src/material/dropdown.dart';
 export 'src/material/flat_button.dart';
 export 'src/material/flexible_space_bar.dart';

packages/flutter/lib/src/material/drawer_divider.dart → packages/flutter/lib/src/material/divider.dart

@@ -6,20 +6,29 @@ import 'package:flutter/widgets.dart';
 
 import 'theme.dart';
 
-class DrawerDivider extends StatelessComponent {
-  const DrawerDivider({ Key key }) : super(key: key);
+class Divider extends StatelessComponent {
+  Divider({ Key key, this.height: 16.0, this.indent: 0.0, this.color }) : super(key: key) {
+    assert(height >= 1.0);
+  }
+
+  final double height;
+  final double indent;
+  final Color color;
 
   Widget build(BuildContext context) {
+    final double bottom = (height ~/ 2.0).toDouble();
     return new Container(
       height: 0.0,
+      margin: new EdgeDims.only(
+        top: height - bottom - 1.0,
+        left: indent,
+        bottom: bottom
+      ),
       decoration: new BoxDecoration(
         border: new Border(
-          bottom: new BorderSide(
-            color: Theme.of(context).dividerColor
-          )
+          bottom: new BorderSide(color: color ?? Theme.of(context).dividerColor)
         )
-      ),
-      margin: const EdgeDims.symmetric(vertical: 8.0)
+      )
     );
   }
 }

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

@@ -6,6 +6,7 @@ import 'dart:async';
 
 import 'package:flutter/widgets.dart';
 
+import 'divider.dart';
 import 'icon.dart';
 import 'icon_button.dart';
 import 'icon_theme.dart';
@@ -26,20 +27,36 @@ const double _kMenuVerticalPadding = 8.0;
 const double _kMenuWidthStep = 56.0;
 const double _kMenuScreenPadding = 8.0;
 
-class PopupMenuItem<T> extends StatelessComponent {
+abstract class PopupMenuEntry<T> extends StatelessComponent {
+  PopupMenuEntry({ Key key }) : super(key: key);
+
+  double get height;
+  T get value => null;
+  bool get enabled => true;
+}
+
+class PopupMenuDivider extends PopupMenuEntry<dynamic> {
+  PopupMenuDivider({ Key key, this.height: 16.0 }) : super(key: key);
+
+  final double height;
+
+  Widget build(BuildContext context) => new Divider(height: height);
+}
+
+class PopupMenuItem<T> extends PopupMenuEntry<T> {
   PopupMenuItem({
     Key key,
     this.value,
     this.enabled: true,
-    this.hasDivider: false,
     this.child
   }) : super(key: key);
 
   final T value;
   final bool enabled;
-  final bool hasDivider;
   final Widget child;
 
+  double get height => _kMenuItemHeight;
+
   Widget build(BuildContext context) {
     final ThemeData theme = Theme.of(context);
     TextStyle style = theme.text.subhead;
@@ -49,7 +66,7 @@ class PopupMenuItem<T> extends StatelessComponent {
     Widget item = new DefaultTextStyle(
       style: style,
       child: new Baseline(
-        baseline: _kMenuItemHeight - _kBaselineOffsetFromBottom,
+        baseline: height - _kBaselineOffsetFromBottom,
         child: child
       )
     );
@@ -63,11 +80,8 @@ class PopupMenuItem<T> extends StatelessComponent {
 
     return new MergeSemantics(
       child: new Container(
-        height: _kMenuItemHeight,
+        height: height,
         padding: const EdgeDims.symmetric(horizontal: _kMenuHorizontalPadding),
-        decoration: !hasDivider ? null : new BoxDecoration(
-          border: new Border(bottom: new BorderSide(color: theme.dividerColor))
-        ),
         child: item
       )
     );
@@ -172,10 +186,10 @@ class _PopupMenu<T> extends StatelessComponent {
 }
 
 class _PopupMenuRouteLayout extends OneChildLayoutDelegate {
-  _PopupMenuRouteLayout(this.position, this.selectedIndex);
+  _PopupMenuRouteLayout(this.position, this.selectedItemOffset);
 
   final ModalPosition position;
-  final int selectedIndex;
+  final double selectedItemOffset;
 
   BoxConstraints getConstraintsForChild(BoxConstraints constraints) {
     return new BoxConstraints(
@@ -195,8 +209,8 @@ class _PopupMenuRouteLayout extends OneChildLayoutDelegate {
     double y = position?.top
       ?? (position?.bottom != null ? size.height - (position.bottom - childSize.height) : _kMenuScreenPadding);
 
-    if (selectedIndex != -1)
-      y -= (_kMenuItemHeight * selectedIndex) + _kMenuVerticalPadding + _kMenuItemHeight / 2.0;
+    if (selectedItemOffset != null)
+      y -= selectedItemOffset + _kMenuVerticalPadding + _kMenuItemHeight / 2.0;
 
     if (x < _kMenuScreenPadding)
       x = _kMenuScreenPadding;
@@ -224,7 +238,7 @@ class _PopupMenuRoute<T> extends PopupRoute<T> {
   }) : super(completer: completer);
 
   final ModalPosition position;
-  final List<PopupMenuItem<T>> items;
+  final List<PopupMenuEntry<T>> items;
   final dynamic initialValue;
   final int elevation;
 
@@ -242,19 +256,20 @@ class _PopupMenuRoute<T> extends PopupRoute<T> {
   Color get barrierColor => null;
 
   Widget buildPage(BuildContext context, Animation<double> animation, Animation<double> forwardAnimation) {
-    int selectedIndex = -1;
+    double selectedItemOffset = null;
     if (initialValue != null) {
-      for (int i = 0; i < items.length; i++)
-        if (initialValue == items[i].value) {
-          selectedIndex = i;
+      selectedItemOffset = 0.0;
+      for (int i = 0; i < items.length; i++) {
+        if (initialValue == items[i].value)
           break;
-        }
+        selectedItemOffset += items[i].height;
+      }
     }
     final Size screenSize = MediaQuery.of(context).size;
     return new ConstrainedBox(
       constraints: new BoxConstraints(maxWidth: screenSize.width, maxHeight: screenSize.height),
       child: new CustomOneChildLayout(
-        delegate: new _PopupMenuRouteLayout(position, selectedIndex),
+        delegate: new _PopupMenuRouteLayout(position, selectedItemOffset),
         child: new _PopupMenu(route: this)
       )
     );
@@ -269,7 +284,7 @@ class _PopupMenuRoute<T> extends PopupRoute<T> {
 Future/*<T>*/ showMenu/*<T>*/({
   BuildContext context,
   ModalPosition position,
-  List<PopupMenuItem/*<T>*/> items,
+  List<PopupMenuEntry/*<T>*/> items,
   dynamic/*=T*/ initialValue,
   int elevation: 8
 }) {
@@ -305,7 +320,7 @@ class PopupMenuButton<T> extends StatefulComponent {
     this.child
   }) : super(key: key);
 
-  final List<PopupMenuItem<T>> items;
+  final List<PopupMenuEntry<T>> items;
   final T initialValue;
   final PopupMenuItemSelected<T> onSelected;
   final String tooltip;