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works in debug but throws Unhandled in release build
Nice work - much appreciated however.. Compiling in release mode throws this: Unhandled Exception: LateInitializationError: Local 'result' has not been initialized.
it seems to be related to the following line in builders/widget.dart WidgetsBinding.instance!.addPostFrameCallback(_captureImage);
Symptom: perfect in debug, blank screen in release
Fixing it is beyond my skill as I'm just learning.
E/flutter (18180): #2 _PageTurnWidgetState._captureImage (package:ssv1/book_screen/builders/widget.dart:40) E/flutter (18180): #3 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144) E/flutter (18180): #4 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090) E/flutter (18180): #5 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:998) E/flutter (18180): #6 _rootRun (dart:async/zone.dart:1354) E/flutter (18180): #7 _CustomZone.run (dart:async/zone.dart:1258) E/flutter (18180): #8 _CustomZone.runGuarded (dart:async/zone.dart:1162) E/flutter (18180): #9 _invoke (dart:ui/hooks.dart:167) E/flutter (18180): #10 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:259) E/flutter (18180): #11 _drawFrame (dart:ui/hooks.dart:126) E/flutter (18180): E/flutter (18180): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: LateInitializationError: Local 'result' has not been initialized. E/flutter (18180): #0 LateError._throwLocalNotInitialized (dart:_internal-patch/internal_patch.dart:208) E/flutter (18180): #1 RenderObject.debugNeedsPaint (package:flutter/src/rendering/object.dart:2112) E/flutter (18180): #2 _PageTurnWidgetState._captureImage (package:ssv1/book_screen/builders/widget.dart:40) E/flutter (18180): #3 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144) E/flutter (18180): #4 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090) E/flutter (18180): #5 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:998) E/flutter (18180): #6 _rootRun (dart:async/zone.dart:1354) E/flutter (18180): #7 _CustomZone.run (dart:async/zone.dart:1258) E/flutter (18180): #8 _CustomZone.runGuarded (dart:async/zone.dart:1162) E/flutter (18180): #9 _invoke (dart:ui/hooks.dart:167) E/flutter (18180): #10 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:259) E/flutter (18180): #11 _drawFrame (dart:ui/hooks.dart:126) E/flutter (18180): E/flutter (18180): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: LateInitializationError: Local 'result' has not been initialized. E/flutter (18180): #0 LateError._throwLocalNotInitialized (dart:_internal-patch/internal_patch.dart:208) E/flutter (18180): #1 RenderObject.debugNeedsPaint (package:flutter/src/rendering/object.dart:2112) E/flutter (18180): #2 _PageTurnWidgetState._captureImage (package:ssv1/book_screen/builders/widget.dart:40) E/flutter (18180): #3 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144) E/flutter (18180): #4 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090) E/flutter (18180): #5 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:998) E/flutter (18180): #6 _rootRun (dart:async/zone.dart:1354) E/flutter (18180): #7 _CustomZone.run (dart:async/zone.dart:1258) E/flutter (18180): #8 _CustomZone.runGuarded (dart:async/zone.dart:1162) E/flutter (18180): #9 _invoke (dart:ui/hooks.dart:167) E/flutter (18180): #10 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:259) E/flutter (18180): #11 _drawFrame (dart:ui/hooks.dart:126) E/flutter (18180): E/flutter (18180): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: LateInitializationError: Local 'result' has not been initialized. E/flutter (18180): #0 LateError._throwLocalNotInitialized (dart:_internal-patch/internal_patch.dart:208) E/flutter (18180): #1 RenderObject.debugNeedsPaint (package:flutter/src/rendering/object.dart:2112) E/flutter (18180): #2 _PageTurnWidgetState._captureImage (package:ssv1/book_screen/builders/widget.dart:40) E/flutter (18180): #3 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144) E/flutter (18180): #4 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090) E/flutter (18180): #5 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:998) E/flutter (18180): #6 _rootRun (dart:async/zone.dart:1354) E/flutter (18180): #7 _CustomZone.run (dart:async/zone.dart:1258) E/flutter (18180): #8 _CustomZone.runGuarded (dart:async/zone.dart:1162) E/flutter (18180): #9 _invoke (dart:ui/hooks.dart:167) E/flutter (18180): #10 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:259) E/flutter (18180): #11 _drawFrame (dart:ui/hooks.dart:126) E/flutter (18180): E/flutter (18180): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: LateInitializationError: Local 'result' has not been initialized. E/flutter (18180): #0 LateError._throwLocalNotInitialized (dart:_internal-patch/internal_patch.dart:208) E/flutter (18180): #1 RenderObject.debugNeedsPaint (package:flutter/src/rendering/object.dart:2112) E/flutter (18180): #2 _PageTurnWidgetState._captureImage (package:ssv1/book_screen/builders/widget.dart:40) E/flutter (18180): #3 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144) E/flutter (18180): #4 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090) E/flutter (18180): #5 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:998) E/flutter (18180): #6 _rootRun (dart:async/zone.dart:1354) E/flutter (18180): #7 _CustomZone.run (dart:async/zone.dart:1258) E/flutter (18180): #8 _CustomZone.runGuarded (dart:async/zone.dart:1162) E/flutter (18180): #9 _invoke (dart:ui/hooks.dart:167) E/flutter (18180): #10 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:259) E/flutter (18180): #11 _drawFrame (dart:ui/hooks.dart:126) E/flutter (18180): E/flutter (18180): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: LateInitializationError: Local 'result' has not been initialized. E/flutter (18180): #0 LateError._throwLocalNotInitialized (dart:_internal-patch/internal_patch.dart:208) E/flutter (18180): #1 RenderObject.debugNeedsPaint (package:flutter/src/rendering/object.dart:2112) E/flutter (18180): #2 _PageTurnWidgetState._captureImage (package:ssv1/book_screen/builders/widget.dart:40) E/flutter (18180): #3 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144) E/flutter (18180): #4 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090) E/flutter (18180): #5 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:998) E/flutter (18180): #6 _rootRun (dart:async/zone.dart:1354) E/flutter (18180): #7 _CustomZone.run (dart:async/zone.dart:1258) E/flutter (18180): #8 _CustomZone.runGuarded (dart:async/zone.dart:1162) E/flutter (18180): #9 _invoke (dart:ui/hooks.dart:167) E/flutter (18180): #10 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:259) E/flutter (18180): #11 _drawFrame (dart:ui/hooks.dart:126)
(The following has failed to resolve) Downgrade to stable, cleanup, cache etc etc, copy to new project, compile with --no-shrink... all failed,
- Debug works perfectly with zero output problems reported on real phone, emulator, windows and chrome builds.
- Release compile fails on all platforms in exactly the same way.
After a while of edit and test, I have found a quick fix about this problem, you could change the function _captureImage to like this and it will work on release build, (You 'll need to copy this library to your own directory to edit PageTurnWidget file)
void _captureImage(Duration timeStamp) async { await Future.delayed(const Duration(milliseconds: 20)); final pixelRatio = MediaQuery.of(context).devicePixelRatio; final boundary = _boundaryKey.currentContext?.findRenderObject() as RenderRepaintBoundary; // if (boundary.debugNeedsPaint) { // await Future.delayed(const Duration(milliseconds: 20)); // return _captureImage(timeStamp); // } final image = await boundary.toImage(pixelRatio: pixelRatio); setState(() => _image = image); }
Thanks mate - it works. I was hoping for better performance once I could get it to work in release mode but unfortunately its still unusably slow . I might look into how to make the performance better. If you find anything please make sure you post it.
