_DropdownMenuState#f9cfe(tickers: tracking 1 ticker) was disposed with an active Ticker

[ryanhz]

flutter: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞════════════════════════
The following assertion was thrown while finalizing the widget
tree:
_DropdownMenuStatef9cfe(tickers: tracking 1 ticker) was disposed
with an active Ticker.
_DropdownMenuState 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
_DropdownMenuStatef9cfe(lifecycle state: created, tickers:
tracking 3 tickers))
The stack trace when the _WidgetTicker was actually created was:
0 new Ticker.
(package:flutter/src/scheduler/ticker.dart:64:40)
1 new Ticker
(package:flutter/src/scheduler/ticker.dart:66:6)
2 new _WidgetTicker
(package:flutter/src/widgets/ticker_provider.dart:225:80)
3
__DropdownMenuState&DropdownState&TickerProviderStateMixin.createTicker
(package:flutter/src/widgets/ticker_provider.dart:161:34)
4 new AnimationController
(package:flutter/src/animation/animation_controller.dart:245:21)
5 _DropdownMenuState.initState
(package:dropdown_menu/_src/dropdown_menu.dart:132:27)
6 StatefulElement._firstBuild
(package:flutter/src/widgets/framework.dart:4033:58)
7 ComponentElement.mount
(package:flutter/src/widgets/framework.dart:3902:5)
8 Element.inflateWidget
(package:flutter/src/widgets/framework.dart:3084:14)
9 Element.updateChild
(package:flutter/src/widgets/framework.dart:2887:12)
10 RenderObjectElement.updateChildren
(package:flutter/src/widgets/framework.dart:4875:32)
11 MultiChildRenderObjectElement.update
(package:flutter/src/widgets/framework.dart:5208:17)
12 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
13 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
14 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
15 ProxyElement.update
(package:flutter/src/widgets/framework.dart:4219:5)
16 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
17 RenderObjectElement.updateChildren
(package:flutter/src/widgets/framework.dart:4817:32)
18 MultiChildRenderObjectElement.update
(package:flutter/src/widgets/framework.dart:5208:17)
19 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
20 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
21 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
22 ProxyElement.update
(package:flutter/src/widgets/framework.dart:4219:5)
23 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
24 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
25 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
26 StatefulElement.update
(package:flutter/src/widgets/framework.dart:4085:5)
27 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
28 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
29 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
30 ProxyElement.update
(package:flutter/src/widgets/framework.dart:4219:5)
31 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
32 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
33 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
34 ProxyElement.update
(package:flutter/src/widgets/framework.dart:4219:5)
35 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
36 RenderObjectElement.updateChildren
(package:flutter/src/widgets/framework.dart:4817:32)
37 MultiChildRenderObjectElement.update
(package:flutter/src/widgets/framework.dart:5208:17)
38 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
39 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
40 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
41 StatefulElement.update
(package:flutter/src/widgets/framework.dart:4085:5)
42 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
43 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
44 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
45 ProxyElement.update
(package:flutter/src/widgets/framework.dart:4219:5)
46 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
47 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
48 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
49 StatefulElement.update
(package:flutter/src/widgets/framework.dart:4085:5)
50 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
51 SingleChildRenderObjectElement.update
(package:flutter/src/widgets/framework.dart:5099:14)
52 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
53 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
54 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
55 StatelessElement.update
(package:flutter/src/widgets/framework.dart:3981:5)
56 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
57 SingleChildRenderObjectElement.update
(package:flutter/src/widgets/framework.dart:5099:14)
58 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
59 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
60 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
61 StatefulElement.update
(package:flutter/src/widgets/framework.dart:4085:5)
62 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
63 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
64 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
65 StatefulElement.update
(package:flutter/src/widgets/framework.dart:4085:5)
66 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
67 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
68 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
69 ProxyElement.update
(package:flutter/src/widgets/framework.dart:4219:5)
70 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
71 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
72 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
73 ProxyElement.update
(package:flutter/src/widgets/framework.dart:4219:5)
74 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
75 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
76 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
77 StatefulElement.update
(package:flutter/src/widgets/framework.dart:4085:5)
78 Element.updateChild
(package:flutter/src/widgets/framework.dart:2876:15)
79 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:3935:16)
80 Element.rebuild
(package:flutter/src/widgets/framework.dart:3721:5)
81 BuildOwner.buildScope
(package:flutter/src/widgets/framework.dart:2340:33)
82
_WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame
(package:flutter/src/widgets/binding.dart:700:20)
83
_WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback
(package:flutter/src/rendering/binding.dart:285:5)
84
_WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback
(package:flutter/src/scheduler/binding.dart:1016:15)
85
_WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame
(package:flutter/src/scheduler/binding.dart:958:9)
86
_WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame
(package:flutter/src/scheduler/binding.dart:874:5)
90 _invoke (dart:ui/hooks.dart:236:10)
91 _drawFrame (dart:ui/hooks.dart:194:3)
(elided 3 frames from package dart:async)

When the exception was thrown, this was the stack:
0 __DropdownMenuState&DropdownState&TickerProviderStateMixin.dispose. (package:flutter/src/widgets/ticker_provider.dart:178:13)
1 __DropdownMenuState&DropdownState&TickerProviderStateMixin.dispose (package:flutter/src/widgets/ticker_provider.dart:191:6)
2 _DropdownMenuState.dispose (package:dropdown_menu/_src/dropdown_menu.dart:147:11)
3 StatefulElement.unmount (package:flutter/src/widgets/framework.dart:4107:12)
4 _InactiveElements._unmount (package:flutter/src/widgets/framework.dart:1737:13)
5 ListIterable.forEach (dart:_internal/iterable.dart:39:13)
6 _InactiveElements._unmountAll (package:flutter/src/widgets/framework.dart:1746:25)
7 BuildOwner.finalizeTree. (package:flutter/src/widgets/framework.dart:2426:27)
8 BuildOwner.lockState (package:flutter/src/widgets/framework.dart:2258:15)
9 BuildOwner.finalizeTree (package:flutter/src/widgets/framework.dart:2425:7)
10 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:702:18)
11 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:285:5)
12 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1016:15)
13 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:958:9)
14 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:874:5)
18 _invoke (dart:ui/hooks.dart:236:10)
19 _drawFrame (dart:ui/hooks.dart:194:3)
(elided 3 frames from package dart:async)

[basharalbashier]

has anyone got a way out?

even trying _controller.dispose(); everywhere never work!