Tickers used by AnimationControllers should be disposed by calling dispose()

[belatarmohammed]

I am working with flutter_gauge. Thanks for the great work.

════════ Exception caught by animation library ═════════════════════════════════════════════════════
The following assertion was thrown while notifying listeners for AnimationController:
setState() called after dispose(): _FlutterGaugeMainState#57037(lifecycle state: defunct, not mounted, tickers: tracking 1 ticker)

This error happens if you call setState() on a State object for a widget that no longer appears in the widget tree (e.g., whose parent widget no longer includes the widget in its build). This error can occur when code calls setState() from a timer or an animation callback.

The preferred solution is to cancel the timer or stop listening to the animation in the dispose() callback. Another solution is to check the "mounted" property of this object before calling setState() to ensure the object is still in the tree.
This error might indicate a memory leak if setState() is being called because another object is retaining a reference to this State object after it has been removed from the tree. To avoid memory leaks, consider breaking the reference to this object during dispose().

When the exception was thrown, this was the stack: 
#0      State.setState.<anonymous closure> (package:flutter/src/widgets/framework.dart:1112:9)
#1      State.setState (package:flutter/src/widgets/framework.dart:1147:6)
#2      new _FlutterGaugeMainState.<anonymous closure> (package:flutter_gauge/fluttergauge.dart:89:9)
#3      AnimationLocalListenersMixin.notifyListeners (package:flutter/src/animation/listener_helpers.dart:124:19)
#4      AnimationController.value= (package:flutter/src/animation/animation_controller.dart:362:5)
...
The AnimationController notifying listeners was: AnimationController#c0c4a(⏮ 0.000; paused)

════════ (5) Exception caught by animation library ═════════════════════════════════════════════════
'package:flutter/src/widgets/framework.dart': Failed assertion: line 3867 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
════════════════════════════════════════════════════════════════════════════════════════════════════

════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
The following assertion was thrown while finalizing the widget tree:
_FlutterGaugeMainState#89854(tickers: tracking 1 ticker) was disposed with an active Ticker.

_FlutterGaugeMainState 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 _FlutterGaugeMainState#89854(lifecycle state: created, no widget, not mounted, 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      new _FlutterGaugeMainState (package:flutter_gauge/fluttergauge.dart:84:41)
#6      FlutterGaugeMain.createState (package:flutter_gauge/fluttergauge.dart:60:47)
#7      new StatefulElement (package:flutter/src/widgets/framework.dart:4306:25)
#8      StatefulWidget.createElement (package:flutter/src/widgets/framework.dart:809:38)
#9      Element.inflateWidget (package:flutter/src/widgets/framework.dart:3189:40)
#10     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#11     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#12     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#13     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#14     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#15     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#16     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#17     MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5551:32)
#18     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#19     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#20     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#21     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#22     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#23     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#24     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#25     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#26     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#27     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#28     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#29     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#30     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#31     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#32     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
#33     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#34     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#35     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#36     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#37     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#38     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#39     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#40     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#41     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#42     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
#43     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#44     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#45     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#46     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#47     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
#48     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
#49     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
#50     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
#51     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5452:14)
#52     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#53     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5161:32)
#54     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5561:17)
#55     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#56     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#57     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#58     StatelessElement.update (package:flutter/src/widgets/framework.dart:4298:5)
#59     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#60     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#61     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#62     ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5)
#63     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#64     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#65     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#66     ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5)
#67     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#68     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5161:32)
#69     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5561:17)
#70     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#71     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#72     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#73     StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
#74     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#75     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#76     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#77     ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5)
#78     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#79     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#80     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#81     StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
#82     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#83     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5452:14)
#84     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#85     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#86     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#87     StatelessElement.update (package:flutter/src/widgets/framework.dart:4298:5)
#88     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#89     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5452:14)
#90     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#91     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#92     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#93     StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
#94     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#95     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#96     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#97     StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
#98     Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#99     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#100    Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#101    ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5)
#102    Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#103    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#104    Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#105    ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5)
#106    Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#107    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#108    Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#109    StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
#110    Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)
#111    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
#112    Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
#113    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2432:33)
#114    WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:773:20)
#115    RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:283:5)
#116    SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1102:15)
#117    SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1041:9)
#118    SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:957:5)
#122    _invoke (dart:ui/hooks.dart:259:10)
#123    _drawFrame (dart:ui/hooks.dart:217:3)
(elided 3 frames from package dart:async)

[ghost]

I have the same problem, I'm using gauge widget inside listView. I have solved this issue by adding this code:

@override
  void dispose() {    
    percentageAnimationController.dispose();
    subscription.cancel();
    super.dispose();
  }

to the _FlutterGaugeMainState state in fluttergauge.dart file.

Please add the dispose method to the code base

Your gauge widget very awesome thanks :)