Unable to write into Firebase Realtime Database

Question

I have tried diff versions of firebase dependencies and enabled all Google APIs but to no avail.

The rules for my firebase for read and write are both set to true. I want to write Hello in my database, Under the reference Location 1.

My pubyaml dependencies are as follows:

dependencies:
  cloud_firestore: ^2.5.1
  cupertino_icons: ^1.0.2
  firebase_auth: ^3.1.0
  firebase_core: ^1.6.0
  firebase_database: ^7.0.0

My app build Gradle dependencies

dependencies {
    implementation platform('com.google.firebase:firebase-bom:28.4.0')
    implementation 'com.google.firebase:firebase-database'
    implementation 'com.google.firebase:firebase-database'
    implementation 'com.google.firebase:firebase-storage'
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.android.support:multidex:1.0.3'
}

My code

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:trackkit/model/user_model.dart';
import 'package:trackkit/LoginSignup/home_screen.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';


class AddItem extends StatelessWidget{
  AddItem({Key? key}) : super(key: key);
  final FirebaseDatabase database = FirebaseDatabase.instance;
  @override
  Widget build(BuildContext context){
    DatabaseReference location = FirebaseDatabase.instance.reference().child("Location 1");
    
    return Scaffold(
        body:Column(
      children: [
        TextFormField(
          decoration: const InputDecoration(
            border: UnderlineInputBorder(),
            labelText: 'Product name',
          ),
        ),
        ElevatedButton(
          child: const Text('Save'),
          onPressed: () async  {
              await location
                  .push()
                  .set({"hello"});
          },
        ),
      ],
    ),
    );
  }
}

After I pressed the 'Save' Button The console log shows :

E/flutter ( 4825): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Invalid argument: LinkedHashSet len:1
E/flutter ( 4825): #0      StandardMessageCodec.writeValue (package:flutter/src/services/message_codecs.dart:426:7)
E/flutter ( 4825): #1      StandardMessageCodec.writeValue.<anonymous closure> (package:flutter/src/services/message_codecs.dart:423:9)
E/flutter ( 4825): #2      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:400:8)
E/flutter ( 4825): #3      StandardMessageCodec.writeValue (package:flutter/src/services/message_codecs.dart:421:13)
E/flutter ( 4825): #4      StandardMethodCodec.encodeMethodCall (package:flutter/src/services/message_codecs.dart:561:18)
E/flutter ( 4825): #5      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:148:13)
E/flutter ( 4825): #6      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)
E/flutter ( 4825): #7      MethodChannelDatabaseReference.set (package:firebase_database_platform_interface/src/method_channel/method_channel_database_reference.dart:97:42)
E/flutter ( 4825): #8      DatabaseReference.set (package:firebase_database/src/database_reference.dart:72:39)
E/flutter ( 4825): #9      AddItem.build.<anonymous closure> (package:trackkit/Screens/addnewitem.dart:30:20)
E/flutter ( 4825): #10     AddItem.build.<anonymous closure> (package:trackkit/Screens/addnewitem.dart:28:22)
E/flutter ( 4825): #11     _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:989:21)
E/flutter ( 4825): #12     GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:193:24)
E/flutter ( 4825): #13     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:608:11)
E/flutter ( 4825): #14     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:296:5)
E/flutter ( 4825): #15     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:230:7)
E/flutter ( 4825): #16     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:558:9)
E/flutter ( 4825): #17     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:94:12)
E/flutter ( 4825): #18     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:139:9)
E/flutter ( 4825): #19     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:400:8)
E/flutter ( 4825): #20     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:137:18)
E/flutter ( 4825): #21     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:123:7)
E/flutter ( 4825): #22     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:440:19)
E/flutter ( 4825): #23     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:420:22)
E/flutter ( 4825): #24     RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:278:11)
E/flutter ( 4825): #25     GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:374:7)
E/flutter ( 4825): #26     GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:338:5)
E/flutter ( 4825): #27     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:296:7)
E/flutter ( 4825): #28     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:279:7)
E/flutter ( 4825): #29     _rootRunUnary (dart:async/zone.dart:1444:13)
E/flutter ( 4825): #30     _CustomZone.runUnary (dart:async/zone.dart:1335:19)
E/flutter ( 4825): #31     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1244:7)
E/flutter ( 4825): #32     _invoke1 (dart:ui/hooks.dart:185:10)
E/flutter ( 4825): #33     PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:293:7)
E/flutter ( 4825): #34     _dispatchPointerDataPacket (dart:ui/hooks.dart:98:31)

I have been trying for 2 days, any help will be greatly appreciated !

Answer 1

In a more general way, I'd say you need to make sure the data you're sending to Firebase is in the right format.

For example, make sure you're sending JSON, and not entities.

Answer 2

You'd need to set a key-value pair if you're trying to write with curly braces ({"msg" : "hello"}). If not, then you just need to remove the curly brace and write it as ("hello") as mentioned by puf. More details can be read in the docs.