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| 1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 import 'animated_component.dart'; | |
| 6 import '../animation/animated_value.dart'; | |
| 7 import '../animation/curves.dart'; | |
| 8 import '../fn.dart'; | |
| 9 import '../theme/colors.dart'; | |
| 10 import 'dart:math' as math; | |
| 11 import 'dart:sky' as sky; | |
| 12 import 'material.dart'; | |
| 13 | |
| 14 const double _kWidth = 304.0; | |
| 15 const double _kMinFlingVelocity = 0.4; | |
| 16 const double _kBaseSettleDurationMS = 246.0; | |
| 17 const double _kMaxSettleDurationMS = 600.0; | |
| 18 const Curve _kAnimationCurve = parabolicRise; | |
| 19 | |
| 20 typedef void DrawerStatusChangeHandler (bool showing); | |
| 21 | |
| 22 class DrawerController { | |
| 23 | |
| 24 DrawerController(this.onStatusChange) { | |
| 25 position = new AnimatedValue(-_kWidth, onChange: _checkValue); | |
| 26 } | |
| 27 final DrawerStatusChangeHandler onStatusChange; | |
| 28 AnimatedValue position; | |
| 29 | |
| 30 bool _oldClosedState = true; | |
| 31 void _checkValue() { | |
| 32 var newClosedState = isClosed; | |
| 33 if (onStatusChange != null && _oldClosedState != newClosedState) { | |
| 34 onStatusChange(!newClosedState); | |
| 35 _oldClosedState = newClosedState; | |
| 36 } | |
| 37 } | |
| 38 | |
| 39 bool get isClosed => position.value == -_kWidth; | |
| 40 bool get _isMostlyClosed => position.value <= -_kWidth / 2; | |
| 41 void toggle(_) => _isMostlyClosed ? _open() : _close(); | |
| 42 | |
| 43 void handleMaskTap(_) => _close(); | |
| 44 void handlePointerDown(_) => position.stop(); | |
| 45 | |
| 46 void handlePointerMove(sky.PointerEvent event) { | |
| 47 if (position.isAnimating) | |
| 48 return; | |
| 49 position.value = math.min(0.0, math.max(position.value + event.dx, -_kWidth)
); | |
| 50 } | |
| 51 | |
| 52 void handlePointerUp(_) { | |
| 53 if (!position.isAnimating) | |
| 54 _settle(); | |
| 55 } | |
| 56 | |
| 57 void handlePointerCancel(_) { | |
| 58 if (!position.isAnimating) | |
| 59 _settle(); | |
| 60 } | |
| 61 | |
| 62 void _open() => _animateToPosition(0.0); | |
| 63 | |
| 64 void _close() => _animateToPosition(-_kWidth); | |
| 65 | |
| 66 void _settle() => _isMostlyClosed ? _close() : _open(); | |
| 67 | |
| 68 void _animateToPosition(double targetPosition) { | |
| 69 double distance = (targetPosition - position.value).abs(); | |
| 70 if (distance != 0) { | |
| 71 double targetDuration = distance / _kWidth * _kBaseSettleDurationMS; | |
| 72 double duration = math.min(targetDuration, _kMaxSettleDurationMS); | |
| 73 position.animateTo(targetPosition, duration, curve: _kAnimationCurve); | |
| 74 } | |
| 75 } | |
| 76 | |
| 77 void handleFlingStart(event) { | |
| 78 double direction = event.velocityX.sign; | |
| 79 double velocityX = event.velocityX.abs() / 1000; | |
| 80 if (velocityX < _kMinFlingVelocity) | |
| 81 return; | |
| 82 | |
| 83 double targetPosition = direction < 0.0 ? -_kWidth : 0.0; | |
| 84 double distance = (targetPosition - position.value).abs(); | |
| 85 double duration = distance / velocityX; | |
| 86 | |
| 87 if (distance > 0) | |
| 88 position.animateTo(targetPosition, duration, curve: linear); | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 class Drawer extends AnimatedComponent { | |
| 93 // TODO(abarth): We need a better way to become a container for absolutely | |
| 94 // positioned elements. | |
| 95 static final Style _style = new Style(''' | |
| 96 transform: translateX(0);'''); | |
| 97 | |
| 98 static final Style _maskStyle = new Style(''' | |
| 99 background-color: black; | |
| 100 will-change: opacity;''' | |
| 101 ); | |
| 102 | |
| 103 static final Style _contentStyle = new Style(''' | |
| 104 background-color: ${Grey[50]}; | |
| 105 will-change: transform; | |
| 106 width: ${_kWidth}px;''' | |
| 107 ); | |
| 108 | |
| 109 List<UINode> children; | |
| 110 int level; | |
| 111 DrawerController controller; | |
| 112 | |
| 113 double _position; | |
| 114 | |
| 115 Drawer({ | |
| 116 Object key, | |
| 117 this.controller, | |
| 118 this.children, | |
| 119 this.level: 0 | |
| 120 }) : super(key: key) { | |
| 121 animateField(controller.position, #_position); | |
| 122 } | |
| 123 | |
| 124 UINode build() { | |
| 125 String maskInlineStyle = 'opacity: ${(_position / _kWidth + 1) * 0.5}'; | |
| 126 String contentInlineStyle = 'transform: translateX(${_position}px)'; | |
| 127 | |
| 128 var mask = new EventListenerNode( | |
| 129 new Container( | |
| 130 style: _maskStyle, | |
| 131 inlineStyle: maskInlineStyle | |
| 132 ), | |
| 133 onGestureTap: controller.handleMaskTap, | |
| 134 onGestureFlingStart: controller.handleFlingStart | |
| 135 ); | |
| 136 | |
| 137 Material content = new Material( | |
| 138 content: new Container( | |
| 139 style: _contentStyle, | |
| 140 inlineStyle: contentInlineStyle, | |
| 141 children: children | |
| 142 ), | |
| 143 level: level); | |
| 144 | |
| 145 return new EventListenerNode( | |
| 146 new FillStackContainer( | |
| 147 style: _style, | |
| 148 children: [ mask, content ] | |
| 149 ), | |
| 150 onPointerDown: controller.handlePointerDown, | |
| 151 onPointerMove: controller.handlePointerMove, | |
| 152 onPointerUp: controller.handlePointerUp, | |
| 153 onPointerCancel: controller.handlePointerCancel | |
| 154 ); | |
| 155 } | |
| 156 } | |
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