【发布时间】：2022-12-25 19:12:40
【问题描述】：
import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_core/firebase_core.dart';
void main() async {
//Run this first
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Smart Bin',
home: new HomePageWidget(),
);
}
}
class HomePageWidget extends StatefulWidget {
const HomePageWidget({Key key}) : super(key: key);
@override
_HomePageWidgetState createState() => _HomePageWidgetState();
}
class _HomePageWidgetState extends State<HomePageWidget> {
final scaffoldKey = GlobalKey<ScaffoldState>();
final currentBinRecord = FirebaseFirestore.instance.collection("current_bin");
@override
Widget build(BuildContext context) {
return Scaffold(
key: scaffoldKey,
appBar: AppBar(
title: Text(
'SmartBin',
),
),
body: SafeArea(
child: GestureDetector(
onTap: () => FocusScope.of(context).unfocus(),
child: Column(
mainAxisSize: MainAxisSize.max,
children: [
Expanded(
child: StreamBuilder<List<CurrentBinRecord>>(
stream: queryCurrentBinRecord(
queryBuilder: (currentBinRecord) =>
currentBinRecord.orderBy('level', descending: true),
),
builder: (context, snapshot) {
// Customize what your widget looks like when it's loading.
if (!snapshot.hasData) {
return Center(
child: SizedBox(
width: 50,
height: 50,
child: CircularProgressIndicator(),
),
);
}
List<CurrentBinRecord> listViewCurrentBinRecordList =
snapshot.data;
return ListView.builder(
padding: EdgeInsets.zero,
scrollDirection: Axis.vertical,
itemCount: listViewCurrentBinRecordList.length,
itemBuilder: (context, listViewIndex) {
final listViewCurrentBinRecord =
listViewCurrentBinRecordList[listViewIndex];
return Row(
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Text(
listViewCurrentBinRecord.area,
),
Text(
listViewCurrentBinRecord.level.toString(),
),
],
);
},
);
},
),
),
],
),
),
),
);
}
}
第一个错误是：
child: StreamBuilder<List<CurrentBinRecord>>
名称“CurrentBinRecord”不是类型，因此不能用作类型参数。 尝试将名称更正为现有类型，或定义名为“CurrentBinRecord”的类型。
第二个错误是：
stream: queryCurrentBinRecord未为类型“_HomePageWidgetState”定义方法“queryCurrentBinRecord”。 尝试将名称更正为现有方法的名称，或定义名为“queryCurrentBinRecord”的方法。
第三个错误是：
List<CurrentBinRecord> listViewCurrentBinRecordList = snapshot.data;名称“CurrentBinRecord”不是类型，因此不能用作类型参数。 尝试将名称更正为现有类型，或定义名为“CurrentBinRecord”的类型。
【问题讨论】：
标签： android flutter firebase dart google-cloud-firestore