Merge pull request #2884 from HansMuller/scrollbar_thumb

Scrollbar thumb color, etc

examples/material_gallery/lib/demo/two_level_list_demo.dart

@@ -9,24 +9,21 @@ class TwoLevelListDemo extends StatelessWidget {
   Widget build(BuildContext context) {
     return new Scaffold(
       appBar: new AppBar(title: new Text('Expand/Collapse List Control')),
-      body: new Padding(
-        padding: const EdgeInsets.all(0.0),
-        child: new TwoLevelList(
-          type: MaterialListType.oneLine,
-          items: <Widget>[
-            new TwoLevelListItem(title: new Text('Top')),
-            new TwoLevelSublist(
-              title: new Text('Sublist'),
-              children: <Widget>[
-                new TwoLevelListItem(title: new Text('One')),
-                new TwoLevelListItem(title: new Text('Two')),
-                new TwoLevelListItem(title: new Text('Free')),
-                new TwoLevelListItem(title: new Text('Four'))
-              ]
-            ),
-            new TwoLevelListItem(title: new Text('Bottom'))
-          ]
-        )
+      body: new TwoLevelList(
+        type: MaterialListType.oneLine,
+        items: <Widget>[
+          new TwoLevelListItem(title: new Text('Top')),
+          new TwoLevelSublist(
+            title: new Text('Sublist'),
+            children: <Widget>[
+              new TwoLevelListItem(title: new Text('One')),
+              new TwoLevelListItem(title: new Text('Two')),
+              new TwoLevelListItem(title: new Text('Free')),
+              new TwoLevelListItem(title: new Text('Four'))
+            ]
+          ),
+          new TwoLevelListItem(title: new Text('Bottom'))
+        ]
       )
     );
   }

packages/flutter/lib/src/gestures/arena.dart

@@ -54,7 +54,7 @@ class _GestureArena {
 
   /// If a gesture attempts to win while the arena is still open, it becomes the
   /// "eager winnner". We look for an eager winner when closing the arena to new
-  /// participants, and if there is one, we resolve the arena it its favour at
+  /// participants, and if there is one, we resolve the arena in its favor at
   /// that time.
   GestureArenaMember eagerWinner;
 

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

@@ -6,6 +6,7 @@ import 'package:flutter/widgets.dart';
 
 import 'constants.dart';
 import 'scrollbar_painter.dart';
+import 'theme.dart';
 
 enum MaterialListType {
   oneLine,
@@ -44,7 +45,15 @@ class MaterialList extends StatefulWidget {
 }
 
 class _MaterialListState extends State<MaterialList> {
-  ScrollbarPainter _scrollbarPainter = new ScrollbarPainter();
+  ScrollbarPainter _scrollbarPainter;
+
+  @override
+  void initState() {
+    super.initState();
+    _scrollbarPainter = new ScrollbarPainter(
+      getThumbColor: () => Theme.of(context).highlightColor
+    );
+  }
 
   @override
   Widget build(BuildContext context) {

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

@@ -10,16 +10,20 @@ const double _kMinScrollbarThumbLength = 18.0;
 const double _kScrollbarThumbGirth = 6.0;
 const Duration _kScrollbarThumbFadeDuration = const Duration(milliseconds: 300);
 
+typedef Color GetThumbColor();
+
 class ScrollbarPainter extends ScrollableListPainter {
+  ScrollbarPainter({ GetThumbColor getThumbColor }) {
+    this.getThumbColor = getThumbColor ?? _defaultThumbColor;
+  }
 
+  GetThumbColor getThumbColor;
   double _opacity = 0.0;
-  int get _alpha => (_opacity * 0xFF).round();
 
-  // TODO(hansmuller): thumb color should come from ThemeData.
-  Color get thumbColor => const Color(0xFF9E9E9E);
+  Color _defaultThumbColor() => const Color(0xFF9E9E9E);
 
   void paintThumb(PaintingContext context, Rect thumbBounds) {
-    final Paint paint = new Paint()..color = thumbColor.withAlpha(_alpha);
+    final Paint paint = new Paint()..color = getThumbColor().withOpacity(_opacity);
     context.canvas.drawRect(thumbBounds, paint);
   }
 
@@ -54,7 +58,7 @@ class ScrollbarPainter extends ScrollableListPainter {
 
   @override
   void paint(PaintingContext context, Offset offset) {
-    if (_alpha == 0)
+    if (_opacity == 0.0)
       return;
     paintScrollbar(context, offset);
   }