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74575775bd
This fixes some theoretical bugs whereby we were using hashCode to try
to get unique keys for objects, but really we wanted object identity.
It also lays the groundwork for a new GlobalKey concept.
I tried to keep the impact on the code minimal, which is why the "Key"
constructor is actually a factory that returns a StringKey. The code
has this class hierarchy:
```
KeyBase
|
Key--------------+---------------+
| | |
StringKey ObjectKey UniqueKey
```
...where the constructors are Key and Key.stringify (StringKey),
Key.fromObjectIdentity (ObjectKey), and Key.unique (UniqueKey).
We could instead of factory methods use regular constructors with the
following hierarchy:
```
KeyBase
|
LocalKey---------+---------------+
| | |
Key ObjectIdentityKey UniqueKey
```
...with constructors Key, Key.stringify, ObjectIdentityKey, and
UniqueKey, but I felt that that was maybe a more confusing hierarchy.
I don't have a strong opinion on this.
45 lines
922 B
Dart
45 lines
922 B
Dart
// Copyright 2015 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'package:sky/widgets/basic.dart';
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abstract class ButtonBase extends StatefulComponent {
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ButtonBase({ Key key, this.highlight: false }) : super(key: key);
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bool highlight;
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void syncFields(ButtonBase source) {
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highlight = source.highlight;
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}
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void _handlePointerDown(_) {
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setState(() {
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highlight = true;
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});
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}
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void _handlePointerUp(_) {
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setState(() {
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highlight = false;
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});
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}
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void _handlePointerCancel(_) {
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setState(() {
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highlight = false;
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});
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}
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Widget build() {
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return new Listener(
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child: buildContent(),
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onPointerDown: _handlePointerDown,
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onPointerUp: _handlePointerUp,
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onPointerCancel: _handlePointerCancel
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);
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}
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Widget buildContent();
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}
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