Flutter 如何获得通过颤振的总时间-使用定时器颤振
我有一个计时器，它有一个小的动画，是一个圆圈围绕它。从另一个路由调用计时器开始（Flutter 如何获得通过颤振的总时间-使用定时器颤振,flutter,flutter-layout,flutter-animation,flutter-timer,Flutter,Flutter Layout,Flutter Animation,Flutter Timer,我有一个计时器，它有一个小的动画，是一个圆圈围绕它。从另一个路由调用计时器开始（ExamTimer（大小：40.0），）。当我导航到另一条路线时，会出现以下错误： ════════ Exception caught by widgets library ═══════════════════════════════════════════════════════ The following assertion was thrown while finalizing the widget tree
ExamTimer（大小：40.0），════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
The following assertion was thrown while finalizing the widget tree:
ExamTimerState#c1b45(tickers: tracking 1 ticker) was disposed with an active Ticker.
ExamTimerState created a Ticker via its TickerProviderStateMixin, but at the time dispose() was called on the mixin, that Ticker was still active. All Tickers must be disposed before calling super.dispose().
Tickers used by AnimationControllers should be disposed by calling dispose() on the AnimationController itself. Otherwise, the ticker will leak.
The offending ticker was: _WidgetTicker(created by ExamTimerState#c1b45(lifecycle state: created, tickers: tracking 0 tickers))
The stack trace when the _WidgetTicker was actually created was:
#0 new Ticker.<anonymous closure> (package:flutter/src/scheduler/ticker.dart:66:40)
#1 new Ticker (package:flutter/src/scheduler/ticker.dart:68:6)
#2 new _WidgetTicker (package:flutter/src/widgets/ticker_provider.dart:237:80)
#3 TickerProviderStateMixin.createTicker (package:flutter/src/widgets/ticker_provider.dart:168:34)
#4 new AnimationController (package:flutter/src/animation/animation_controller.dart:245:21)
#5 ExamTimerState.initState (package:azmoonasli/models/ExamTimer.dart:27:18)
#6 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4355:58)
#7 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#8 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#9 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5551:32)
#10 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#11 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#12 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#13 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#14 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#15 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#16 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#17 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#18 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#19 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#20 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#21 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#22 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#23 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#24 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#25 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#26 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#27 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#28 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#29 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#30 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#31 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#32 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#33 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#34 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#35 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#36 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#37 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#38 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#39 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#40 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#41 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#42 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5551:32)
#43 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#44 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#45 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#46 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#47 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#48 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#49 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#50 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5551:32)
#51 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#52 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#53 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#54 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#55 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#56 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#57 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#58 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#59 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#60 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#61 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#62 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#63 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#64 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#65 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#66 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#67 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#68 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#69 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#70 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#71 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#72 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#73 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#74 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#75 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#76 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#77 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#78 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#79 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#80 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#81 ParentDataElement.mount (package:flutter/src/widgets/framework.dart:4617:11)
#82 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#83 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5551:32)
#84 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#85 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#86 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#87 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#88 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#89 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#90 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#91 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#92 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#93 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#94 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#95 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#96 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#97 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#98 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#99 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#100 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#101 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#102 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#103 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#104 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#105 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#106 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#108 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#109 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#110 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#111 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#112 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#113 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#114 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#115 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#116 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#117 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#118 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#119 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#120 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#121 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#122 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#123 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#124 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#125 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#126 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#127 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#128 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#129 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#130 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#131 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#132 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#133 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#134 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#135 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#136 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#137 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#138 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#139 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#140 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#141 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#142 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#143 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#144 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#145 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#146 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#147 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#148 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#149 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#150 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#151 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#152 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#153 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#154 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#155 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#156 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#157 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#158 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#159 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#160 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#161 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#162 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#163 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#164 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#165 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#166 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#167 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#168 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#169 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#170 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#171 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#172 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#173 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#174 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#175 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#176 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#177 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#178 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#179 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#180 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#181 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#182 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#183 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#184 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#185 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#186 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#187 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#188 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#189 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#190 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#191 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#192 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#193 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#194 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#195 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#196 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#197 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#198 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#199 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#200 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#201 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#202 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#203 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#204 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#205 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#206 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#207 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#208 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#209 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#210 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#211 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#212 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#213 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#217 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#224 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#225 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#226 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#227 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#228 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#229 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#230 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#231 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#232 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#233 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#234 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#235 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#236 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#237 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#238 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#239 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#240 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#241 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#242 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5219:32)
#243 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5561:17)
#244 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#245 _TheatreElement.update (package:flutter/src/widgets/overlay.dart:605:16)
#246 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#247 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#249 StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
#250 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#251 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#252 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#253 ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5)
#254 _InheritedNotifierElement.update (package:flutter/src/widgets/inherited_notifier.dart:94:11)
#255 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#256 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5452:14)
#257 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#258 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#259 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#260 StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
#261 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#262 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5452:14)
#263 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#264 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5452:14)
#265 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#266 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#267 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#268 StatelessElement.update (package:flutter/src/widgets/framework.dart:4298:5)
#269 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#270 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#272 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2432:33)
#273 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:773:20)
#274 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:283:5)
#275 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1102:15)
#276 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1041:9)
#277 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:957:5)
#281 _invoke (dart:ui/hooks.dart:259:10)
#282 _drawFrame (dart:ui/hooks.dart:217:3)
(elided 3 frames from package dart:async)
When the exception was thrown, this was the stack:
#0 TickerProviderStateMixin.dispose.<anonymous closure> (package:flutter/src/widgets/ticker_provider.dart:185:13)
#1 TickerProviderStateMixin.dispose (package:flutter/src/widgets/ticker_provider.dart:203:6)
#2 StatefulElement.unmount (package:flutter/src/widgets/framework.dart:4435:12)
#3 _InactiveElements._unmount (package:flutter/src/widgets/framework.dart:1748:13)
#4 _InactiveElements._unmount.<anonymous closure> (package:flutter/src/widgets/framework.dart:1746:7)
...
════════════════════════════════════════════════════════════════════════════════════════════════════
════════ widgets库捕获到异常═══════════════════════════════════════════════════════
完成小部件树时引发了以下断言：
ExamTimerState#c1b45（股票代码：跟踪1股票代码）与活动股票代码一起处理。
ExamTimerState通过其TickerProviderStateMixin创建了一个Ticker，但在mixin上调用dispose（）时，该Ticker仍处于活动状态。在调用super.dispose（）之前，必须先处理所有标记。
应通过调用AnimationController本身上的dispose（）来处理AnimationController使用的标记。否则，自动售票机将泄漏。
有问题的代码是：_Widgeticker（由ExamTimerState创建#c1b45（生命周期状态：已创建，代码：跟踪0个代码））
实际创建_widgeticker时的堆栈跟踪为：
#0新的股票代码。（软件包：颤振/src/scheduler/ticker.dart:66:40）
#1个新的自动售票机（软件包：颤振/src/scheduler/Ticker.dart:68:6）
#2个新的widgeticker（包：flatter/src/widgets/ticker\u provider.dart:237:80）
#3 TickerProviderStateMixin.createTicker（包：flatter/src/widgets/ticker\u provider.dart:168:34）
#4个新的AnimationController（包：颤振/src/animation/animation_控制器。dart:245:21）
#5 ExamTimerState.initState（包：azmoonasli/models/ExamTimer.dart:27:18）
#6 StatefulElement.\u firstBuild（包：flatter/src/widgets/framework.dart:4355:58）
#7 ComponentElement.mount（包：flatter/src/widgets/framework.dart:4201:5）
#8 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#9 MultiChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5551:32）
#10 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#11 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#12 ComponentElement.performRebuild（包：flatter/src/widgets/framework.dart:4243:16）
#13.Element.rebuild（包：flatter/src/widgets/framework.dart:3947:5）
#14 ComponentElement._firstBuild（包：flatter/src/widgets/framework.dart:4206:5）
#15 StatefulElement.\u firstBuild（包：flatter/src/widgets/framework.dart:4381:11）
#16 ComponentElement.mount（包：flatter/src/widgets/framework.dart:4201:5）
#17 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#18 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#19 ComponentElement.performRebuild（包：flatter/src/widgets/framework.dart:4243:16）
#20 Element.rebuild（包：flatter/src/widgets/framework.dart:3947:5）
#21 ComponentElement._firstBuild（包：flatter/src/widgets/framework.dart:4206:5）
#22 ComponentElement.mount（包：flatter/src/widgets/framework.dart:4201:5）
#23 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#24 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#25 SingleChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5445:14）
#26 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#27 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#28 SingleChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5445:14）
#29 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#30 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#31 SingleChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5445:14）
#32 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#33 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#34 SingleChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5445:14）
#35 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#36 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#37 ComponentElement.performRebuild（包：flatter/src/widgets/framework.dart:4243:16）
#38 Element.rebuild（包：flatter/src/widgets/framework.dart:3947:5）
#39 ComponentElement._firstBuild（包：flatter/src/widgets/framework.dart:4206:5）
#40 ComponentElement.mount（包：flatter/src/widgets/framework.dart:4201:5）
#41 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#42 MultiChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5551:32）
#43 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#44 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#45 SingleChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5445:14）
#46 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#47 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#48 SingleChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5445:14）
#49 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#50 MultiChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5551:32）
#51 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#52 Element.updateChild（包：flatter/src/widgets/framework.dart:2988:12）
#53 SingleChildRenderObjectElement.mount（包：flatter/src/widgets/framework.dart:5445:14）
#54 Element.inflateWidget（包：flatter/src/widgets/framework.dart:3194:14）
#55.updateChi元素
import 'package:flutter/material.dart';
import 'dart:math' as math;
class ExamTimer extends StatefulWidget {
final double size;
ExamTimer({@required this.size, });
@override
ExamTimerState createState() => ExamTimerState();
}
class ExamTimerState extends State<ExamTimer> with TickerProviderStateMixin {
AnimationController controller;
String get timerString {
Duration duration = controller.duration * controller.value;
return '${duration.inMinutes}:${(duration.inSeconds % 60).toString().padLeft(2, '0')}';
}
@override
void initState() {
super.initState();
controller = AnimationController(
vsync: this,
duration: Duration(minutes: 20),
);
}
@override
Widget build(BuildContext context) {
ThemeData themeData = Theme.of(context);
controller.reverse(from: controller.value == 0.0 ? 1.0 : controller.value);
return Stack(
alignment: Alignment.center,
children: <Widget>[ AnimatedBuilder(
animation: controller,
builder: (BuildContext context, Widget child) {
return CustomPaint(
size: Size(widget.size, widget.size),
painter: TimerPainter(
animation: controller,
backgroundColor: Colors.white,
color: themeData.indicatorColor,
));
},
),
AnimatedBuilder(
animation: controller,
builder: (BuildContext context, Widget child) {
return Text(
timerString,
style: TextStyle(fontSize: 12.0),
);
}),
],
);
}
}
class TimerPainter extends CustomPainter {
TimerPainter({
this.animation,
this.backgroundColor,
this.color,
}) : super(repaint: animation);
final Animation<double> animation;
final Color backgroundColor, color;
@override
void paint(Canvas canvas, Size size) {
Paint paint = Paint()
..color = backgroundColor
..strokeWidth = 5.0
..strokeCap = StrokeCap.round
..style = PaintingStyle.stroke;
canvas.drawCircle(size.center(Offset.zero), size.width / 2.0, paint);
paint.color = color;
double progress = (1.0 - animation.value) * 2 * math.pi;
canvas.drawArc(Offset.zero & size, math.pi * 1.5, progress, false, paint);
}
@override
bool shouldRepaint(TimerPainter old) {
return animation.value != old.animation.value ||
color != old.color ||
backgroundColor != old.backgroundColor;
}
}
controller?.dispose();
yourTimer.cancel();
//start a stopwatch
final watch = StopWatch()..start();
//Eleapsed time
watch.eleapsed //returns a Duration
//Stop it
watch.stop()
//You can also reset when you return to your page
watch.reset();
//Start
final timer = Timer.periodic(Duration(seconds:1), (Timer ticker){
if(ticker.tick == 2){//Wait for 1*2 seconds
//Navigate here
}
//Total eleapsed time
timer.tick*yourDurationUnit // used when creating this timer
)