Remove ButtonState

Clients should just use a GestureDetector (or an InkWell) instead.

examples/game/lib/main.dart

@@ -151,16 +151,18 @@ class TextureButton extends StatefulComponent {
   TextureButtonState createState() => new TextureButtonState();
 }
 
-class TextureButtonState extends ButtonState<TextureButton> {
-  Widget buildContent(BuildContext context) {
-    return new Listener(
+class TextureButtonState extends State<TextureButton> {
+  bool _highlight = false;
+
+  Widget build(BuildContext context) {
+    return new GestureDetector(
       child: new Container(
         width: config.width,
         height: config.height,
         child: new CustomPaint(
           callback: paintCallback,
           token: new _TextureButtonToken(
-            highlight,
+            _highlight,
             config.texture,
             config.textureDown,
             config.width,
@@ -168,9 +170,22 @@ class TextureButtonState extends ButtonState<TextureButton> {
           )
         )
       ),
-      onPointerUp: (_) {
+      onTapDown: () {
+        setState(() {
+          _highlight = true;
+        });
+      },
+      onTap: () {
+        setState(() {
+          _highlight = false;
+        });
         if (config.onPressed != null)
           config.onPressed();
+      },
+      onTapCancel: () {
+        setState(() {
+          _highlight = false;
+        });
       }
     );
   }
@@ -180,7 +195,7 @@ class TextureButtonState extends ButtonState<TextureButton> {
       return;
 
     canvas.save();
-    if (highlight && config.textureDown != null) {
+    if (_highlight && config.textureDown != null) {
       // Draw down state
       canvas.scale(size.width / config.textureDown.size.width, size.height / config.textureDown.size.height);
       config.textureDown.drawTexture(canvas, Point.origin, new Paint());

packages/flutter/lib/src/widgets/button_state.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/src/widgets/basic.dart';
-import 'package:sky/src/widgets/framework.dart';
-
-abstract class ButtonState<T extends StatefulComponent> extends State<T> {
-  bool highlight = false;
-
-  void _handlePointerDown(_) {
-    setState(() {
-      highlight = true;
-    });
-  }
-
-  void _handlePointerUp(_) {
-    setState(() {
-      highlight = false;
-    });
-  }
-
-  void _handlePointerCancel(_) {
-    setState(() {
-      highlight = false;
-    });
-  }
-
-  Widget build(BuildContext context) {
-    return new Listener(
-      onPointerDown: _handlePointerDown,
-      onPointerUp: _handlePointerUp,
-      onPointerCancel: _handlePointerCancel,
-      child: buildContent(context)
-    );
-  }
-
-  Widget buildContent(BuildContext context);
-}

packages/flutter/lib/src/widgets/drawer_item.dart

@@ -8,7 +8,6 @@ import 'package:sky/gestures.dart';
 import 'package:sky/material.dart';
 import 'package:sky/painting.dart';
 import 'package:sky/src/widgets/basic.dart';
-import 'package:sky/src/widgets/button_state.dart';
 import 'package:sky/src/widgets/framework.dart';
 import 'package:sky/src/widgets/icon.dart';
 import 'package:sky/src/widgets/ink_well.dart';

packages/flutter/lib/src/widgets/floating_action_button.dart

@@ -4,7 +4,6 @@
 
 import 'package:sky/gestures.dart';
 import 'package:sky/src/widgets/basic.dart';
-import 'package:sky/src/widgets/button_state.dart';
 import 'package:sky/src/widgets/framework.dart';
 import 'package:sky/src/widgets/icon.dart';
 import 'package:sky/src/widgets/ink_well.dart';

packages/flutter/lib/src/widgets/material_button.dart

@@ -4,7 +4,6 @@
 
 import 'package:sky/gestures.dart';
 import 'package:sky/src/widgets/basic.dart';
-import 'package:sky/src/widgets/button_state.dart';
 import 'package:sky/src/widgets/framework.dart';
 import 'package:sky/src/widgets/ink_well.dart';
 import 'package:sky/src/widgets/material.dart';

packages/flutter/lib/widgets.dart

@@ -9,7 +9,6 @@ export 'src/widgets/animated_container.dart';
 export 'src/widgets/app.dart';
 export 'src/widgets/basic.dart';
 export 'src/widgets/binding.dart';
-export 'src/widgets/button_state.dart';
 export 'src/widgets/card.dart';
 export 'src/widgets/checkbox.dart';
 export 'src/widgets/date_picker.dart';