Map不是类型'Map'的子类型。
Map不是类型'Map'的子类型。
我在Firebase上创建了一个实时数据库，并希望将存储的数据显示在Flutter上，但我注意到每当我打开用于显示存储数据的屏幕时，加载了一段时间的CircularProgressIndicator后，控制台上会打印出一个错误消息：“类型'_Map
import 'package:flutter/material.dart';
import 'package:firebase_database/firebase_database.dart';
class DailyTipsScreen extends StatefulWidget {
const DailyTipsScreen({Key? key}) : super(key: key);
@override
State
}
class _DailyTipsScreenState extends State
late DatabaseReference tipsRef;
@override
void initState() {
super.initState();
tipsRef = FirebaseDatabase.instance.ref().child('tips');
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Tips'),
),
body: StreamBuilder
stream: tipsRef.onValue,
builder: (context, snapshot) {
if (!snapshot.hasData) {
return const Center(
child: CircularProgressIndicator(),
);
}
final tips =
final dataSnapshot = snapshot.data!.snapshot;
(dataSnapshot.value as Map
tips.add(value);
});
return ListView.builder(
itemCount: tips.length,
itemBuilder: (context, index) {
final tip = tips[index];
final homeTeamName = tip['home_team_name'];
final awayTeamName = tip['away_team_name'];
final scoreFulltime = tip['score_fulltime'];
final bettingTips = tip['betting_tips'];
final odds =
bettingTips.forEach((key, value) {
odds.add(value['odds']);
});
final oddsString = odds.join(' / ');
return ListTile(
title: Text('$homeTeamName vs $awayTeamName'),
subtitle: Text('Score: $scoreFulltime, Odds: $oddsString'),
);
},
);
},
),
);
}
}