使用带Flutter的Firebase数据库的权限被拒绝？

Question

我正在学习使用Firebase，我想使用firebase数据库执行Crud操作。

​

Firebase规则是：

    "rules": {
    ".read": true,
    ".write": true
  }

码

import 'package:flutter/material.dart';
import 'package:firebase_database/firebase_database.dart';
void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(

        primarySwatch: Colors.red,
        // This makes the visual density adapt to the platform that you run
        // the app on. For desktop platforms, the controls will be smaller and
        // closer together (more dense) than on mobile platforms.
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: FirebaseDemoScreen(),
    );
  }
}

class FirebaseDemoScreen extends StatelessWidget  {
  final databaseReference = FirebaseDatabase.instance.reference();
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return  Scaffold(
      appBar: AppBar(
        title: Text('Firebase Connect'),
      ),
      body: Center(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: <Widget>[

              RaisedButton(
                child: Text('Create Record'),
                onPressed: () {
                  createRecord();
                },
              ),

              RaisedButton(
                child: Text('View Record'),
                onPressed: () {
                  getData();
                },
              ),
              RaisedButton(
                child: Text('Update Record'),
                onPressed: () {
                  updateData();
                },
              ),
              RaisedButton(
                child: Text('Delete Record'),
                onPressed: () {
                  deleteData();
                },
              ),
            ],
          )
      ), //center
    );
  }



void createRecord(){
  databaseReference.child("1").set({
    'title': 'Mastering EJB',
    'description': 'Programming Guide for J2EE'
  });
  databaseReference.child("2").set({
    'title': 'Flutter in Action',
    'description': 'Complete Programming Guide to learn Flutter'
  });
}
void getData(){
  databaseReference.once().then((DataSnapshot snapshot) {
    print('Data : ${snapshot.value}');
  });
}

void updateData(){
  databaseReference.child('1').update({
    'description': 'J2EE complete Reference'
  });
}

void deleteData(){
  databaseReference.child('1').remove();
}
}

它导致一个错误：

错误:flutter/lib/ui/ui_dart_state.cc(166)未处理异常: PlatformException(-3，权限被拒绝)，)E/颤振(31408)：#0 (package:flutter/src/services/message_codecs.dart:569:7) E/颤振(31408)：#1 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:159:18) E/颤振(31408)：E/颤振(31408)：#2 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:332:12) E/颤振(31408)：#3 (package:firebase_database/src/database_reference.dart:74:31) E/ DatabaseReference.set (31408)：#4 FirebaseDemoScreen.createRecord (包:FirebaseDemoScreen.createRecord/main.dart:77:32)E/DatabaseReference.set (31408)：#5 FirebaseDemoScreen.build。(包装:学习/主要。飞镖:42:19)E/ _InkResponseState._handleTap (31408)：#6 _InkResponseState._handleTap _InkResponseState.build E/颤振(31408)：#7 _InkResponseState.build。(package:flutter/src/material/ink_well.dart:1059:38) E/颤振(31408)：#8 (package:flutter/src/gestures/recognizer.dart:182:24) E/颤振(31408)：#9 TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:522:11) E/颤振(31408)：#10 BaseTapGestureRecognizer._checkUp (包装:颤振/src/手势/踢踏舞:282:5)E/颤振(31408)：#11 (package:flutter/src/gestures/recognizer.dart:475:9) BaseTapGestureRecognizer.handlePrimaryPointer (包装:颤振/src/手势/踢踏舞:217:7)E/颤振(31408)：#12 PrimaryPointerGestureRecognizer.handleEvent BaseTapGestureRecognizer.handlePrimaryPointer/颤振(31408)：#13 PointerRouter._dispatch PointerRouter._dispatchEventToRoutes E/颤振(31408)：#14 PointerRouter._dispatchEventToRoutes。(package:flutter/src/gestures/pointer_router.dart:122:9) E/颤振(31408)：#15 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8) E/颤振(31408)：#16 PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:120:18) E/颤振(31408)：#17 PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:106:7)E/颤振(31408)：#18 (package:flutter/src/gestures/binding.dart:218:19) E/颤振(31408)：#19 GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22) E/颤振(31408)：#20 GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7) E/颤振(31408)：#21 GestureBinding._flushPointerEventQueue (包装:GestureBinding.dispatchEvent/src)/手势/绑定。飞镖:102:7)E/颤振(31408)：#22 (package:flutter/src/gestures/binding.dart:86:7) E/颤振(31408)：#23 _rootRunUnary (飞镖:异步/zone.dart:1206:13)E/ _CustomZone.runUnary (31408)：#24 _CustomZone.runUnary(飞镖:1100:19)E/颤振(31408)：#25 _CustomZone.runUnaryGuarded (飞镖:异步)/zone.dart:1005:7) E/颤振(31408)：#26 _invoke1 (飞镖:ui/钩子:10)E/颤振(31408)：#27 _dispatchPointerDataPacket (飞镖:ui/钩子:190:5)

Answer 1

解决了问题--我刚刚更新了Android，然后我重新启动了一次失效缓存并重新启动了android，现在它为我工作了。

误差

 plugin project :firebase_core_web not found

虽然还存在错误，但与防火墙的数据库连接是用相同的代码和防火墙规则构建的。

Answer 2

使规则测试模式为try 1：https://i.stack.imgur.com/Xeeis.png

Answer 3

您可能试图访问错误的位置，请检查您要访问的数据库。

mentioned.

• There

1. 转到蓝色标头
2. 上的"Database“选项，您会发现一个下拉列表，其中表示CloudFi还原Beta将其更改为”实时数据库“
3. 转到规则并将.write .read设置为true

https://github.com/firebase/quickstart-js/issues/239#issuecomment-417862631

https://github.com/firebase/quickstart-js/issues/239#issuecomment-465989989

如果上一个问题没有对你起作用，你可以参考这个问题来获得更多的答案。

https://github.com/firebase/quickstart-js/issues/239