如何将未来列表设置为列表并更新 ListView
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【中文标题】如何将未来列表设置为列表并更新 ListView【英文标题】：How to set a future list to a list and update the ListView 【发布时间】：2020-02-12 06:21:26 【问题描述】：每当我单击按钮时，我都需要更新列表视图， 我尝试了以下代码，但它不能完美运行， 当我单击第一个按钮时，它不会更新任何内容，当我单击第二个按钮时，它会使用第一个按钮列表更新列表，当我单击第三个按钮时，它会使用第二个按钮的列表更新列表。 这是我的代码
import 'package:flutter/material.dart';
import 'products_list.dart';
class HomeScreen extends StatefulWidget
@override
_HomeScreenState createState() => _HomeScreenState();
class _HomeScreenState extends State<HomeScreen>
List<ProductsList> myinitlist = [];
@override
void initState()
super.initState();
myinitlist = List.from(productList);
@override
Widget build(BuildContext context)
return MaterialApp(
home: Scaffold(
body: SafeArea(
child: Column(
children: <Widget>[
Row(
children: <Widget>[
Expanded(
child: Container(
child: SearchBar(),
),
),
Padding(
padding: const EdgeInsets.fromLTRB(4.0, 4.0, 10.0, 4.0),
child: Hero(
tag: 'logo',
child: Image.asset(
'images/iglo_round.png',
height: 30.0,
width: 30.0,
),
),
),
],
),
Padding(
padding: const EdgeInsets.all(5.0),
child: Row(
children: <Widget>[
Expanded(
child: FlatButton(
onPressed: ()
setState(()
//i need to update this list with new items
myinitlist.removeRange(0, myinitlist.length);
getAllProductsInCategory(25504207);
myinitlist = List.from(productList);
);
,
child: Container(
child: Column(
children: <Widget>[
Image.asset(
'images/bulb.png',
width: 100,
height: 100,
),
Text('bulb')
],
),
),
),
),
Expanded(
child: FlatButton(
onPressed: ()
setState(()
//i need to update this list with new items
myinitlist.removeRange(0, myinitlist.length);
getAllProductsInCategory(25504204);
myinitlist = List.from(productList);
);
,
child: Container(
child: Column(
children: <Widget>[
Image.asset(
'images/bulb.png',
width: 100,
height: 100,
),
Text('bulb')
],
),
),
),
),
Expanded(
child: FlatButton(
onPressed: ()
setState(()
//i need to update this list with new items
myinitlist.removeRange(0, myinitlist.length);
getAllProductsInCategory(25504208);
print(myinitlist.length);
);
,
child: Container(
child: Column(
children: <Widget>[
Image.asset(
'images/bulb.png',
width: 100,
height: 100,
),
Text('bulb')
],
),
),
),
),
],
),
),
Flexible(
child: GridView.builder(itemCount: myinitlist.length,
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount
(crossAxisCount: 2),
itemBuilder: (BuildContext context, int index)
return Card(
child: Stack(
children: <Widget>[
GestureDetector(
onTap:()
,
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Expanded(
child: Center(
child: Image.network(myinitlist[index].proThummbnail,
fit: BoxFit.contain,
),
),
flex: 2,
),
Expanded(
child: Center(child: Text(myinitlist[index].proName,
style:
TextStyle(fontSize: 10.0),)),
flex: 1,
)
],
),
)
],
),
);
),
),
],
),
),
),
);
products_list.dart 文件包含以下代码
List<ProductsList> productList = [];
class ProductsList
int proId;
String proName;
String proThummbnail;
ProductsList(@required this.proId,@required this.proName,@required this.proThummbnail);
Future<List<ProductsList>> getAllProductsInCategory(int catid) async
// print(categoryList[0].catId);
String prodInCategoryUrl = 'https://app.ecwid'
'.com/api/v3/12424132/products?token'
'=public_xxxxxxxxxxxx&enabled=true&category=$catid';
Response allProductsInCategory = await get(prodInCategoryUrl);
print(allProductsInCategory.statusCode);
productList.removeRange(0, productList.length);
if(allProductsInCategory.statusCode == 200)
var allProductsInCategoryData = allProductsInCategory.body;
int totalcount = jsonDecode(allProductsInCategoryData)['count'];
for(int i=0;i<totalcount;i++)
// print(jsonDecode(categoryData)['items'][i]['id']);
// print(jsonDecode(categoryData)['items'][i]['name']);
productList.add(
ProductsList(proId: jsonDecode(allProductsInCategoryData)['items'][i]['id'],
proName: jsonDecode(allProductsInCategoryData)
['items'][i]['name'], proThummbnail: jsonDecode
(allProductsInCategoryData)
['items'][i]['thumbnailUrl']
)
);
print('products list length $productList.length');
return productList;
return productList;;
谁能帮我解决这个问题。 提前谢谢你。
【问题讨论】：
【参考方案1】：您的getAllProductsInCategory 是未来，因此您需要等待您的未来解决。尝试在它前面添加await。请注意，您可以在async 方法中使用await
【讨论】：
【参考方案2】：更新此代码
setState(()
//i need to update this list with new items
myinitlist.removeRange(0, myinitlist.length);
getAllProductsInCategory(25504207);
myinitlist = List.from(productList);
);
这样，（第一次更新onPressed: () async ...）//异步**
await getAllProductsInCategory(25504207);
setState(()
//i need to update this list with new items
myinitlist.clear();
myinitlist = List.from(productList);
);
【讨论】：
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