【发布时间】：2021-04-29 04:39:41
【问题描述】：
Flutter 错误：引发了另一个异常：“DiagnosticsProperty”实例。重定向到该页面时显示空白屏幕。
我已成功将文本项目、一张图片和一份 pdf 上传到 firebase 数据库，并且能够在卡片小部件视图和列表瓷砖视图中检索所有这些内容现在我试图在单击列表中的列表项目时获取单个视图查看。
请检查我的代码，当我尝试重定向到所需的检索页面时看到一个空白屏幕。
RetrievePage.dart
import 'dart:async';
import 'dart:io';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:gadjet_inventory/Form/ListTileFeed.dart';
import 'package:gadjet_inventory/Form/ListTiles.dart';
import 'package:gadjet_inventory/main.dart';
import 'package:intl/intl.dart';
import 'package:gadjet_inventory/Form/Data.dart';
import 'package:gadjet_inventory/Form/UploadData.dart';
import 'package:pdf_flutter/pdf_flutter.dart';
// ignore: must_be_immutable
import 'package:url_launcher/url_launcher.dart';
import 'Data.dart';
class RetrievePage extends StatefulWidget {
// String currentEmail;
//RetrievePage(this.currentEmail);
@override
_RetrievePageState createState() => _RetrievePageState();
}
class _RetrievePageState extends State<RetrievePage> {
List<Data> dataList = [];
List<bool> favList = [];
bool searchState = false;
FirebaseAuth auth = FirebaseAuth.instance;
@override
void initState() {
// TODO: implement initState
super.initState();
DatabaseReference referenceData = FirebaseDatabase.instance.reference().child("Data");
referenceData.once().then((DataSnapshot dataSnapShot) {
dataList.clear();
favList.clear();
var keys = dataSnapShot.value.keys;
var values = dataSnapShot.value;
for (var key in keys) {
Data data = new Data(
values [key]['imgUrl'],
values [key]['cattegorrytype'],
values [key]['companyname'],
values [key]['modelname'],
values [key]['seriesname'],
values [key]['serielnumber'],
values [key]['year'],
key
//key is the uploadid
);
dataList.add(data);
auth.currentUser().then((value) {
DatabaseReference reference = FirebaseDatabase.instance.reference().child("Data").child(key).child("Fav")
.child(value.uid).child("state");
reference.once().then((DataSnapshot snapShot){
if(snapShot.value!=null){
if(snapShot.value=="true"){
favList.add(true);
}else{
favList.add(false);
}
}else{
favList.add(false);
}
});
});
}
Timer(Duration(seconds: 1),(){
setState(() {
//
});
});
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(
"List View",
),
actions: <Widget>[
// action button
],
),
body: Center(
child: Container(
child: ListView.separated(
itemBuilder: (BuildContext context, int index) {
Column(
children: <Widget>[
Image.network(
dataList[index].imgUrl != null
? dataList[index].imgUrl
: '',
width: 500,
height: 500,
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
Expanded(
flex: 1,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Text( "Cattegorry Type:- "
"$dataList[index].cattegorrytype",
style: TextStyle(color: Colors.black),
),
),
),
],
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
Expanded(
flex: 1,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Theme(
data: ThemeData(
hintColor: Colors.blue,
),
child: Text( "Company Name:- "
"$dataList[index].companyname",
style: TextStyle(color: Colors.black),
),
),
),
),
Expanded(
flex: 1,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Theme(
data: ThemeData(
hintColor: Colors.blue,
),
child: Text( "Model Name:- "
"$dataList[index].modelname",
style: TextStyle(color: Colors.black),
),
),
),
),
],
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
Expanded(
flex: 1,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Theme(
data: ThemeData(
hintColor: Colors.blue,
),
child: Text( "Series Name:- "
"$dataList[index].seriesname",
style: TextStyle(color: Colors.black),
),
),
),
),
Expanded(
flex: 1,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Theme(
data: ThemeData(
hintColor: Colors.blue,
),
child: Text( "Year Of MFG:- "
"$dataList[index].year",
style: TextStyle(color: Colors.black),
),
),
),
),
],
),
],
);
},
),
),
),
);
}
}
请解决我看到空白屏幕并显示错误“引发另一个异常：'DiagnosticsProperty' 实例”的问题
【问题讨论】：
标签： firebase flutter data-retrieval