Selecting different dates on the calendar throws error: !_debugDuringDeviceUpdate

Question

Hi,

I am using Sfcalendar (Resource View) for my app on the web. When I select a different date and move my cursor somewhere, it throws an error saying using null operator on a null value. This has happened multiple times and because of it, the entire calendar freezes no operation can be done further.

If you guys could fix this, it will be very helpful.

Running on Web:

Error:Unexpectednullvalue. at Object.throw_ [asthrow](http://localhost:55606/dart_sdk.js:5063:11) at Object.nullCheck (http://localhost:55606/dart_sdk.js:5390:30) at sfcalendar._SfCalendarState.new.[_updateMouseHoverPosition](http://localhost:55606/packages/syncfusion_flutter_calendar/src/calendar/views/timeline_view.dart.lib.js:27796:32) at sfcalendar._SfCalendarState.new.[_pointerEnterEvent](http://localhost:55606/packages/syncfusion_flutter_calendar/src/calendar/views/timeline_view.dart.lib.js:27859:42) at http://localhost:55606/packages/syncfusion_flutter_calendar/src/calendar/views/timeline_view.dart.lib.js:29127:49 at Function._handleDeviceUpdateMouseEvents (http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:5073:110) at mouse_tracker.MouseTracker.new.[_handleDeviceUpdate](http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:5018:34) at http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:5045:36 at mouse_tracker.MouseTracker.new.[_deviceUpdatePhase](http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:4983:7) at http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:5032:33 at mouse_tracker.MouseTracker.new.[_monitorMouseConnection](http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:4974:7) at mouse_tracker.MouseTracker.new.updateWithEvent (http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:5031:36) at binding$5.WidgetsFlutterBinding.new.dispatchEvent (http://localhost:55606/packages/flutter/src/rendering/layer.dart.lib.js:5351:44) at binding$5.WidgetsFlutterBinding.new.[_handlePointerEventImmediately](http://localhost:55606/packages/flutter/src/gestures/binding.dart.lib.js:327:14) at binding$5.WidgetsFlutterBinding.new.handlePointerEvent (http://localhost:55606/packages/flutter/src/gestures/binding.dart.lib.js:301:43) at binding$5.WidgetsFlutterBinding.new.[_flushPointerEventQueue](http://localhost:55606/packages/flutter/src/gestures/binding.dart.lib.js:291:14) at binding$5.WidgetsFlutterBinding.new.[_handlePointerDataPacket](http://localhost:55606/packages/flutter/src/gestures/binding.dart.lib.js:282:54) at Object.invoke1 (http://localhost:55606/dart_sdk.js:190231:7) at _engine.EnginePlatformDispatcher.__.invokeOnPointerDataPacket (http://localhost:55606/dart_sdk.js:171674:15) at _engine.PointerBinding.__.[_onPointerData](http://localhost:55606/dart_sdk.js:172556:49) at http://localhost:55606/dart_sdk.js:172984:26 at http://localhost:55606/dart_sdk.js:172951:16 at loggedHandler (http://localhost:55606/dart_sdk.js:172655:11)══╡ EXCEPTION CAUGHT BY SCHEDULER LIBRARY ╞═════════════════════════════════════════════════════════The following assertion was thrown during a scheduler callback:Assertion failed: file:///Users/santhoshramachandran/Downloads/flutter/packages/flutter/lib/src/rendering/mouse_tracker.dart:201:12!_debugDuringDeviceUpdate isnottrueWhen the exception was thrown,this was the stack: dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 251:49 throw_ dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 29:3 assertFailed packages/flutter/src/rendering/mouse_tracker.dart 201:13[_deviceUpdatePhase] packages/flutter/src/rendering/mouse_tracker.dart 353:5 updateAllDevices packages/flutter/src/rendering/binding.dart 380:7
packages/flutter/src/scheduler/binding.dart 1145:15[_invokeFrameCallback] packages/flutter/src/scheduler/binding.dart 1090:9 handleDrawFrame packages/flutter/src/scheduler/binding.dart 996:5[_handleDrawFrame] lib/_engine/engine/platform_dispatcher.dart 1011:13 invoke lib/_engine/engine/platform_dispatcher.dart 159:5 invokeOnDrawFrame lib/_engine/engine.dart 461:45

Running on MacOS:

[ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Null check operator used on a null value
#0      _SfCalendarState._updateMouseHoverPosition (package:syncfusion_flutter_calendar/src/calendar/sfcalendar.dart:4817:44)
#1      _SfCalendarState._pointerEnterEvent (package:syncfusion_flutter_calendar/src/calendar/sfcalendar.dart:4913:5)
#2      _SfCalendarState._addResourcePanel.<anonymous closure> (package:syncfusion_flutter_calendar/src/calendar/sfcalendar.dart:8083:21)
#3      MouseTracker._handleDeviceUpdateMouseEvents (package:flutter/src/rendering/mouse_tracker.dart:409:28)
#4      MouseTracker._handleDeviceUpdate (package:flutter/src/rendering/mouse_tracker.dart:278:5)
#5      MouseTracker.updateWithEvent.<anonymous closure>.<anonymous closure> (package:flutter/src/rendering/mouse_tracker.dart:332:9)
#6      MouseTracker._deviceUpdatePhase (package:flutter/src/rendering/mouse_tracker.dart:206:9)
#7      MouseTracker.updateWithEvent.<anonymous closure> (package:flutter/src/rendering/mouse_tracker.dart:312:7)
#8      MouseTracker._monitorMouseConnection (package:flutter/src/rendering/mouse_tracker.dart:190:9)
#9      MouseTracker.updateWithEvent (package:flutter/src/rendering/mouse_tracker.dart:311:5)
#10     RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:314:20)
#11     GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:374:7)
#12     GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:338:5)
#13     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:296:7)
#14     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:279:7)
#15     _rootRunUnary (dart:async/zone.dart:1442:13)
#16     _CustomZone.runUnary (dart:async/zone.dart:1335:19)
#17     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1244:7)
#18     _invoke1 (dart:ui/hooks.dart:170:10)
#19     PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:331:7)
#20     _dispatchPointerDataPacket (dart:ui/hooks.dart:94:31)

1 Reply

MK Muthulakshmi Kalaiselvan Syncfusion Team January 14, 2022 07:54 AM UTC

Hi,

Thank you for contacting Syncfusion support.

Based on the provided information, we have checked, and we could not reproduce the mentioned issue. It is working fine as expected from our end.

For your reference, we have attached the tested sample.

https://www.syncfusion.com/downloads/support/forum/171946/ze/select-different-dates-1765146253

Please check the sample and let us know if you are still facing the issue. If not, could you please modify the shared sample to replicate the issue, or, if possible, share the calendar code snippets used with the replication procedure, so that we can investigate further and provide you with a potential solution as soon as possible?

Regards,

Muthulakshmi K

Muthulakshmi Kalaiselvan · Answer

Hi, 
 
Thank you for contacting Syncfusion support. 
 
Based on the provided information, we have checked, and we could not reproduce the mentioned issue. It is working fine as expected from our end. 
 
For your reference, we have attached the tested sample.  
https://www.syncfusion.com/downloads/support/forum/171946/ze/select-different-dates-1765146253 
 
Please check the sample and let us know if you are still facing the issue. If not, could you please modify the shared sample to replicate the issue, or, if possible, share the calendar code snippets used with the replication procedure, so that we can investigate further and provide you with a potential solution as soon as possible? 
 
Regards, 
Muthulakshmi K