flutter firebase エラーの原因について

Question

import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:todoapp/main_model.dart';

void main() async{
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter todo',
      home: ChangeNotifierProvider<MainModel>(
        create: (_) => MainModel()..getTodoList(),
            child: Scaffold(
            appBar: AppBar(
              title: Text('flutter todo'),
            ),
            body: Consumer<MainModel>(builder: (context, model, child) {
              final todoList = model.todoList;
                return ListView(
                  children: todoList
                      .map(
                      (todo) => ListTile(
                        title: Text(todo.title),
                      ),
                  ).toList(),
                );
              }
            ),
            floatingActionButton: FloatingActionButton(
              onPressed: (){

              },
              tooltip: 'Increment',
              child: Icon(Icons.add),
            ),
          )
      ),
    );
  }
}

import 'package:cloud_firestore/cloud_firestore.dart';

class Todo{
  Todo(DocumentSnapshot doc){

    this.title = doc.data()['title'];

    final Timestamp timestamp = doc.data()['createdAt'];
    this.createdAt = timestamp.toDate();
  }

  String title;
  DateTime createdAt;
}

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/cupertino.dart';
import 'package:todoapp/todo.dart';

class MainModel extends ChangeNotifier{

  List<Todo> todoList = [];

  Future getTodoList() async {
    final snapshot =
    await FirebaseFirestore.instance.collection('todoList').get();
    final docs = snapshot.docs;
    final todoList = docs.map((doc) => Todo(doc)).toList();
    this.todoList = todoList;
    notifyListeners();
  }
}

###エラー文

W/example.apptod(11143): Accessing hidden method Ldalvik/system/CloseGuard;->close()V (greylist,core-platform-api, linking, allowed)
W/DynamiteModule(11143): Local module descriptor class for providerinstaller not found.
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putInt(Ljava/lang/Object;JI)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putLong(Ljava/lang/Object;JJ)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getObject(Ljava/lang/Object;J)Ljava/lang/Object; (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putObject(Ljava/lang/Object;JLjava/lang/Object;)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getInt(Ljava/lang/Object;J)I (greylist, linking, allowed)
I/DynamiteModule(11143): Considering local module providerinstaller:0 and remote module providerinstaller:0
W/ProviderInstaller(11143): Failed to load providerinstaller module: No acceptable module found. Local version is 0 and remote version is 0.
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getObject(Ljava/lang/Object;J)Ljava/lang/Object; (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putObject(Ljava/lang/Object;JLjava/lang/Object;)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getInt(Ljava/lang/Object;J)I (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putInt(Ljava/lang/Object;JI)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getInt(Ljava/lang/Object;J)I (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putObject(Ljava/lang/Object;JLjava/lang/Object;)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putLong(Ljava/lang/Object;JJ)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putInt(Ljava/lang/Object;JI)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getObject(Ljava/lang/Object;J)Ljava/lang/Object; (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putLong(Ljava/lang/Object;JJ)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getObject(Ljava/lang/Object;J)Ljava/lang/Object; (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getLong(Ljava/lang/Object;J)J (greylist,core-platform-api, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getInt(Ljava/lang/Object;J)I (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putInt(Ljava/lang/Object;JI)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->putObject(Ljava/lang/Object;JLjava/lang/Object;)V (greylist, linking, allowed)
W/example.apptod(11143): Accessing hidden method Lsun/misc/Unsafe;->getInt(Ljava/lang/Object;J)I (greylist, linking, allowed)
D/skia (11143): Shader compilation error
D/skia (11143): ------------------------
D/skia (11143): Errors:
D/skia (11143):

---

一度動作したのですが、ビルドし直すとこのエラーが表示されました。
ググってみたのですがわかりませんでした
よろしくお願いします。

Comments

[mather]

エラー文もテキストとして提示してください。

> ググってみたのですがわかりませんでした
どの部分が重要だと思ってググりましたか？
見た感じほぼ答えになるエラーメッセージが出ていると思うのですが。

[mather]

エラーメッセージが変わりましたね…

Answer 1

android-permission
上記のリンクと同様に
android/app/src/main/AndroidManifest.xml
に権限のリクエストとして
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
をいれてみてはどうでしょうか?

Comments

[kimidoro]

ご回答ありがとうございます。修正してみたのですが、変わりませんでした。（一度は動作しました。）
加え、下記のようなエラーが出てしまったのですが、解決方法をご存じでしたらご教授お願いします。

E/flutter (15132): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: NoSuchMethodError: The method 'toDate' was called on null.
E/flutter (15132): Receiver: null
E/flutter (15132): Tried calling: toDate()
E/flutter (15132): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)
E/flutter (15132): #1 new Todo (package:apptodo/todo.dart:10:32)
E/flutter (15132): #2 MainModel.getTodoListRealtime.<anonymous closure>.<anonymous closure> (package:apptodo/main_model.dart:23:42)
E/flutter (15132): #3 MappedListIterable.elementAt (dart:_internal/iterable.dart:411:31)
E/flutter (15132): #4 ListIterator.moveNext (dart:_internal/iterable.dart:340:26)
E/flutter (15132): #5 new _GrowableList._ofEfficientLengthIterable (dart:core-patch/growable_array.dart:188:27)
E/flutter (15132): #6 new _GrowableList.of (dart:core-patch/growable_array.dart:150:28)
E/flutter (15132): #7 new List.of (dart:core-patch/array_patch.dart:50:28)
E/flutter (15132): #8 ListIterable.toList (dart:_internal/iterable.dart:211:44)
E/flutter (15132): #9 MainModel.getTodoListRealtime.<anonymous closure> (package:apptodo/main_model.dart:23:53)
E/flutter (15132): #10 _rootRunUnary (dart:async/zone.dart:1362:47)
E/flutter (15132): #11 _CustomZone.runUnary (dart:async/zone.dart:1265:19)
E/flutter (15132): #12 _CustomZone.runUnaryGuarded (dart:async/zone.dart:1170:7)
E/flutter (15132): #13 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
E/flutter (15132): #14 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
E/flutter (15132): #15 _ForwardingStreamSubscription._add (dart:async/stream_pipe.dart:123:11)
E/flutter (15132): #16 _MapStream._handleData (dart:async/stream_pipe.dart:218:10)
E/flutter (15132): #17 _ForwardingStreamSubscription._handleData (dart:async/stream_pipe.dart:153:13)
E/flutter (15132): #18 _rootRunUnary (dart:async/zone.dart:1362:47)
E/flutter (15132): #19 _CustomZone.runUnary (dart:async/zone.dart:1265:19)
E/flutter (15132): #20 _CustomZone.runUnaryGuarded (dart:async/zone.dart:1170:7)
E/flutter (15132): #21 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
E/flutter (15132): #22 _DelayedData.perform (dart:async/stream_impl.dart:591:14)
E/flutter (15132): #23 _StreamImplEvents.handleNext (dart:async/stream_impl.dart:706:11)
E/flutter (15132): #24 _PendingEvents.schedule.<anonymous closure> (dart:async/stream_impl.dart:663:7)
E/flutter (15132): #25 _rootRun (dart:async/zone.dart:1346:47)
E/flutter (15132): #26 _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter (15132): #27 _CustomZone.runGuarded (dart:async/zone.dart:1162:7)
E/flutter (15132): #28 _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1202:23)
E/flutter (15132): #29 _rootRun (dart:async/zone.dart:1354:13)
E/flutter (15132): #30 _CustomZone.run (dart:async/zone.dart:1258:19)
E/flutter (15132): #31 _CustomZone.runGuarded (dart:async/zone.dart:1162:7)
E/flutter (15132): #32 _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1202:23)
E/flutter (15132): #33 _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
E/flutter (15132): #34 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)

[endiv]

NoSuchMethodError: The method 'toDate' was called on null.が怪しいですね。https://stackoverflow.com/questions/54985317/unhandled-exception-nosuchmethoderror-the-method-todate-was-called-on-nullを参考に時刻ににnullが入らないように先に入れてみてはどうでしょう

[kimidoro]

ご回答ありがとうございました。
firebaseに登録した時刻のコレクションのスペルミスが原因でした。
ありがとうございました！

[endiv]

コレクションのミスでしたか！僕も一回やってしまった事があったのに特定できず申し訳ないです

[kimidoro]

いえいえこちらこそ
今後、機会がありましたら質問させていただきます。
ありがとうございました！