如何在颤振中访问模型名称/提供程序名称的数据形式实例

Question

我有一个从API获取数据的质询提供程序。我将数据存储在List<Challenge>数组中。在挑战屏幕中，我得到了List<Challenge>数组。现在我得到的是Instance of 'ChallengeModel'.

在ListView.builder()中，如果我这样做challenge[index].title我得到空。

代码如下：

挑战模型：

import 'package:flutter/material.dart';
class ChallengeModel {
int id;
int status;
String title;
String description;
String startDate;
String endDate;
ChallengeModel({
@required id,
@required title,
@required description,
@required startDate,
@required endDate,
@required status,
});

}

在提供程序中，如何在数组中添加ChallengeModel数据：

_challenges.add(
ChallengeModel(
id: result['id'],
title: result['title'],
description: result['description'],
startDate: result['start_date'],
endDate: result['end_date'],
status: finalStatus,
)
);  

挑战屏幕：

@override
Widget build(BuildContext context) {
final challengeProvider = Provider.of<ChallengesProvider>(context);
var challenges = challengeProvider.items;
print(challenges);
return ListView.builder(
itemCount: challenges.length,
itemBuilder: (BuildContext context, int index) {
return Container(
padding: EdgeInsets.symmetric(vertical: 10, horizontal: 20),
child: Card(
child: Column(
children: <Widget>[
Text(
"${challenges[index].title}",
style: Theme.of(context).textTheme.title,
),
],
),
),
);
},
);
}
}

API 数据和上述提供程序项的终端打印结果。

flutter: {
id:3,
group_id:1,
title:Demo Challlenge,
description:<p>lorem epson</p>,
start_date:2019-12-12 00:00:00,
end_date:2020-01-13 00:00:00,
status_id:2,
creator_id:1,
moderator_id:1,
created_at:2019-12-12 14:26:57,
updated_at:2019-12-12 14:26:57,
deleted_at:null,
teams:[
{
id:1,
group_id:1,
name:Havens Blade,
logo:https://source.unsplash.com/random/200x200,
status_id:2,
creator_id:2,
moderator_id:2,
created_at:2019-12-11 01:27:16,
updated_at:2019-12-11 01:27:16,
deleted_at:null,
pivot:{
challenge_id:3,
team_id:1
}
},
{
id:2,
group_id:1,
name:Let's Do it, 
logo: https://source.unsplash.com/random/200x200, 
status_id: 2, 
creator_id: 1, 
moderator_id: 1, 
created_at: 2019-12-11 14:34:36, 
updated_at: 2019-12-11 14:34:36, 
deleted_at: null, 
{
id: 3, 
group_id: 1, 
name: OneMORE, 
logo: https://source.unsplash.com/random/200x200, 
status_id: 2, 
creator_id: 1, 
moderator_id: 1, 
created_at: 2019-12-11 14:35:30, 
updated_at: 2019-12-11 14:35<…>
flutter: --------------------------------------
flutter: challenges final completed
flutter: [Instance of 'ChallengeModel', Instance of 'ChallengeModel', Instance of 'ChallengeModel']

Answer 1

@override
String toString() => 'AllDataModel(data: $data)';
@override
bool operator ==(covariant AllDataModel other) {
if (identical(this, other)) return true;
return other.data == data;
}
@override
int get hashCode => data.hashCode;

Answer 2

模型中缺少this关键字，如下所示。

class ChallengeModel {
int id;
int status;
String title;
String description;
String startDate;
String endDate;
ChallengeModel({
@required this.id,
@required this.title,
@required this.description,
@required this.startDate,
@required this.endDate,
@required this.status,
});

}

由于此.title或任何其他数据无法访问。