初めまして
flutterの勉強のために下記を行おうとしたらスクショのようなエラーが発生しました。
どなたか教えていただけないでしょうか。
やりたいこと
- FirebaseのFirestoreの値を更新(update)する
- FirebaseのFirestoreの値を削除する
解決したいエラー
ボタンをタップするとエラーが出てしまいます。
======== Exception caught by widgets library ======================================================= The following _CastError was thrown building Builder(dirty): Null check operator used on a null value The relevant error-causing widget was: MaterialApp MaterialApp:file:///Users/lukasekine/StudioProjects/flutter_tutorial_3/lib/presentation/main/main.dart:16:12 When the exception was thrown, this was the stack: #0 BookListPage.build.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:flutter_tutorial_3/presentation/book_list/book_list_page.dart:81:31) #1 MaterialPageRoute.buildContent (package:flutter/src/material/page.dart:53:55) #2 MaterialRouteTransitionMixin.buildPage (package:flutter/src/material/page.dart:106:27) #3 _ModalScopeState.build.<anonymous closure>.<anonymous closure> (package:flutter/src/widgets/routes.dart:872:55) #4 Builder.build (package:flutter/src/widgets/basic.dart:7398:48) #5 StatelessElement.build (package:flutter/src/widgets/framework.dart:4827:28) #6 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4754:15) #7 Element.rebuild (package:flutter/src/widgets/framework.dart:4477:5) #8 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4735:5) #9 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4729:5) ... Normal element mounting (170 frames) #179 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3790:14) #180 MultiChildRenderObjectElement.inflateWidget (package:flutter/src/widgets/framework.dart:6422:36) #181 Element.updateChild (package:flutter/src/widgets/framework.dart:3540:18) #182 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5845:32) #183 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6445:17) #184 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #185 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4780:16) #186 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4928:11) #187 Element.rebuild (package:flutter/src/widgets/framework.dart:4477:5) #188 StatefulElement.update (package:flutter/src/widgets/framework.dart:4960:5) #189 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #190 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4780:16) #191 Element.rebuild (package:flutter/src/widgets/framework.dart:4477:5) #192 ProxyElement.update (package:flutter/src/widgets/framework.dart:5108:5) #193 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #194 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4780:16) #195 Element.rebuild (package:flutter/src/widgets/framework.dart:4477:5) #196 ProxyElement.update (package:flutter/src/widgets/framework.dart:5108:5) #197 _InheritedNotifierElement.update (package:flutter/src/widgets/inherited_notifier.dart:111:11) #198 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #199 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6291:14) #200 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #201 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4780:16) #202 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4928:11) #203 Element.rebuild (package:flutter/src/widgets/framework.dart:4477:5) #204 StatefulElement.update (package:flutter/src/widgets/framework.dart:4960:5) #205 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #206 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6291:14) #207 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #208 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6291:14) #209 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #210 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4780:16) #211 Element.rebuild (package:flutter/src/widgets/framework.dart:4477:5) #212 ProxyElement.update (package:flutter/src/widgets/framework.dart:5108:5) #213 Element.updateChild (package:flutter/src/widgets/framework.dart:3501:15) #214 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4780:16) #215 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4928:11) #216 Element.rebuild (package:flutter/src/widgets/framework.dart:4477:5) #217 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2659:19) #218 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:882:21) #219 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:363:5) #220 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144:15) #221 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1081:9) #222 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:995:5) #226 _invoke (dart:ui/hooks.dart:151:10) #227 PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:308:5) #228 _drawFrame (dart:ui/hooks.dart:115:31) (elided 3 frames from dart:async)
参考にしたもの(ほぼ丸パクしました)
- https://www.youtube.com/watch?v=W0oKfFgoKpM&list=PLuLRJz1UnJzFrDuXT5FjsSUPmqD79kUpB&index=6
- https://www.youtube.com/watch?v=q8jzhswdMyU&list=PLuLRJz1UnJz
私のレベルではどのコードを共有したら適切な解決方法をいただけるかわからないため、私の共有アイテムにフォルダをzipファイルでアップしてあります。
ご回答よろしくお願い致します。
↓↓コードが格納されているフォルダ↓↓
https://drive.google.com/file/d/1oERMM4xBv-G-vBkoP2krkVsZskhteG4y/view?usp=sharing