我正在尝试从 api 获取数据并显示在列表或卡片视图中
I am trying to fetch data from api and show in list or card view
enter code here#in extractedData 数据已提取，但我收到一条错误消息 I/flutter (7967): type '(dynamic, dynamic) => Null' is not a subtype of type ' （动态）=> 'f' 的动态'
E/flutter (7967): [错误:flutter/lib/ui/ui_dart_state.cc(209)] 未处理的异常：类型“(dynamic, dynamic) => Null”不是类型“(dynamic) => dynamic”的子类型' 'f'
E/flutter（7967）：#0 CategoryModels.fetchData（包：apiwork/models/category_model.dart:64:7）
E/flutter ( 7967):
Future<void> fetchData() async{
var url = "my api goes here..........";
try{
final response = await http.get(Uri.parse(url));
final extractedData = json.decode(response.body);
final List<CategoryModel> loadedProduct = [];
if(extractedData == null){
return;
}
extractedData.forEach((prodId,productData){
loadedProduct.add(CategoryModel(
id:productData['id'],
image:productData['images'],
name:productData['name'],
));
});
_cItems = loadedProduct;
notifyListeners();
print(_cItems);
}catch(e){
print(e);
throw e;
}
}
#这是我的 home.dart
class HomeScreen extends StatefulWidget {
const HomeScreen({Key? key}) : super(key: key);
@override
_HomeScreenState createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
bool _selected =false;
var _selectedIndex = 1;
var _isInit = true;
var _isLoading = false;
@override
void didChangeDependencies(){
// TODO: implement didChangeDependencies
if(_isInit){
setState(() {
_isLoading = true;
});
Provider.of<CategoryModels>(context).fetchData();
setState(() {
_isLoading = false;
});
}
_isInit = false;
super.didChangeDependencies();
}
void changeAnimatedContainerHeight(bool index){
setState(() {
_selected = index;
_selected = !_selected;
print(_selected);
});
}
void onTapped(var index){
setState(() {
_selectedIndex = index;
});
}
final List<String> imageList = [
'https://th.bing.com/th/id/OIP.ayY5Ok1_cnPjwSRxEQERuwHaEO?pid=ImgDet&w=698&h=399&rs=1',
'https://2qcolg3kl2ha3kfo912rzv2v-wpengine.netdna-ssl.com/wp-content/uploads/sites/8/2017/01/food-1400x550.jpg',
'https://th.bing.com/th/id/OIP.qIMnTRibgveVBeUXxEQwngHaE1?pid=ImgDet&w=1024&h=669&rs=1'
];
@override
Widget build(BuildContext context) {
return GestureDetector(
onTap: (){
FocusManager.instance.primaryFocus?.unfocus();
},
child: Scaffold(
resizeToAvoidBottomInset: false,
appBar: AppBar(
backgroundColor: Colors.transparent,
leading: const Icon(Icons.location_on_outlined,color: Colors.black,),
// title: const Text('Chitwan',style: TextStyle(color: Colors.black),),
elevation: 0,
actions: [
Padding(
padding: const EdgeInsets.only(right: 150.0,top: 5.0),
child: DropdownButton(
value:_selectedIndex,
items:const [
DropdownMenuItem(
child: Text("Chitwan"),
value: 1,
),
DropdownMenuItem(
child: Text("Kathmandu"),
value: 2,
),
DropdownMenuItem(
child: Text("Pokhara"),
value: 3,
),
DropdownMenuItem(
child: Text("Butwal"),
value: 4,
),
DropdownMenuItem(
child: Text("Hetauda"),
value: 5,
),
],
onChanged: onTapped,
),
),
// PopupMenuButton(itemBuilder: (BuildContext context){
// return[
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Chitwan"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Kathmandu"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Pokhara"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Butwal"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Hetauda"),
// )
// ),
// ];
// }),
IconButton(onPressed: (){
Provider.of<AuthProvider>(context,listen: false).logout(context);
}, icon: const Icon(Icons.person,color: Colors.black,)),
IconButton(onPressed: (){}, icon: const Icon(Icons.shopping_cart_outlined,color: Colors.black,)),
],
),
// drawer: AppDrawer(),
// body:BottomNavigation()
body: SingleChildScrollView(
scrollDirection: Axis.vertical,
child: Column(
children: [
Form(
child: Padding(
padding: const EdgeInsets.only(left:2.0),
child: Container(
height: 45.0,
width: 380.0,
decoration:const BoxDecoration(
color: Color(0xFFF2F3F7),
),
child: TextFormField(
decoration: const InputDecoration(
border: OutlineInputBorder(
borderSide: BorderSide.none,
),
icon: Padding(
padding: EdgeInsets.only(left: 5.0),
child: Icon(Icons.search),
),
hintText:'Hi, how can i help you?',
hintStyle: TextStyle(fontSize: 14.0)
),
),
),
),
),
// const SizedBox(height: 10.0),
AnimatedContainer(
height:_selected?220:140,
decoration:const BoxDecoration(
borderRadius: BorderRadius.only(bottomLeft: Radius.circular(40.0),bottomRight: Radius.circular(20.0)),
color: Colors.white,
),
duration: const Duration(seconds: 1),
curve: Curves.fastOutSlowIn,
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
const Expanded(
child: SizedBox(
height:100.0,
child: Padding(
padding: EdgeInsets.only(top: 20.0),
child: CategoryGrid(),
),
),
),
IconButton(onPressed:(){
changeAnimatedContainerHeight(_selected);
}, icon:Icon(_selected?Icons.expand_less:Icons.expand_more),color:Colors.black12,iconSize: 30.0,),
],
),
),
const SizedBox(height: 10.0),
CarouselSlider(
items:imageList.map((e) =>ClipRRect(
borderRadius: BorderRadius.circular(8.0),
child: Stack(
fit: StackFit.expand,
children: [
Padding(
padding: const EdgeInsets.all(15.0),
child: Image.network(e,fit: BoxFit.cover),
)
],
),
) ).toList()
, options: CarouselOptions(viewportFraction: 1,height: 140.0,autoPlay: true,autoPlayAnimationDuration: const Duration(milliseconds: 800),),),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Today's Special",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:150.0,
child: Padding(
padding: EdgeInsets.only(left: 0),
child:TodaySpecialGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Our Partners",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:180.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:OurPartnersGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Our Hotels",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:180.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:OurHotelGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("New Products",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:180.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:NewProductGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Vegetables",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:500.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:VegetableGrid(),
),
),
)
],
),
// const BottomNavigation()
]),
),
),
);
}
}
我认为这可能会解决您的问题：
extractedData.forEach((element){
loadedProduct.add(CategoryModel(
id:element['id'],
image:element!['images'],
name:element['name'],
));
如果您还有其他问题，请告诉我。
enter code here#in extractedData 数据已提取，但我收到一条错误消息 I/flutter (7967): type '(dynamic, dynamic) => Null' is not a subtype of type ' （动态）=> 'f' 的动态'
E/flutter (7967): [错误:flutter/lib/ui/ui_dart_state.cc(209)] 未处理的异常：类型“(dynamic, dynamic) => Null”不是类型“(dynamic) => dynamic”的子类型' 'f'
E/flutter（7967）：#0 CategoryModels.fetchData（包：apiwork/models/category_model.dart:64:7）
E/flutter ( 7967):
Future<void> fetchData() async{
var url = "my api goes here..........";
try{
final response = await http.get(Uri.parse(url));
final extractedData = json.decode(response.body);
final List<CategoryModel> loadedProduct = [];
if(extractedData == null){
return;
}
extractedData.forEach((prodId,productData){
loadedProduct.add(CategoryModel(
id:productData['id'],
image:productData['images'],
name:productData['name'],
));
});
_cItems = loadedProduct;
notifyListeners();
print(_cItems);
}catch(e){
print(e);
throw e;
}
}
#这是我的 home.dart
class HomeScreen extends StatefulWidget {
const HomeScreen({Key? key}) : super(key: key);
@override
_HomeScreenState createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
bool _selected =false;
var _selectedIndex = 1;
var _isInit = true;
var _isLoading = false;
@override
void didChangeDependencies(){
// TODO: implement didChangeDependencies
if(_isInit){
setState(() {
_isLoading = true;
});
Provider.of<CategoryModels>(context).fetchData();
setState(() {
_isLoading = false;
});
}
_isInit = false;
super.didChangeDependencies();
}
void changeAnimatedContainerHeight(bool index){
setState(() {
_selected = index;
_selected = !_selected;
print(_selected);
});
}
void onTapped(var index){
setState(() {
_selectedIndex = index;
});
}
final List<String> imageList = [
'https://th.bing.com/th/id/OIP.ayY5Ok1_cnPjwSRxEQERuwHaEO?pid=ImgDet&w=698&h=399&rs=1',
'https://2qcolg3kl2ha3kfo912rzv2v-wpengine.netdna-ssl.com/wp-content/uploads/sites/8/2017/01/food-1400x550.jpg',
'https://th.bing.com/th/id/OIP.qIMnTRibgveVBeUXxEQwngHaE1?pid=ImgDet&w=1024&h=669&rs=1'
];
@override
Widget build(BuildContext context) {
return GestureDetector(
onTap: (){
FocusManager.instance.primaryFocus?.unfocus();
},
child: Scaffold(
resizeToAvoidBottomInset: false,
appBar: AppBar(
backgroundColor: Colors.transparent,
leading: const Icon(Icons.location_on_outlined,color: Colors.black,),
// title: const Text('Chitwan',style: TextStyle(color: Colors.black),),
elevation: 0,
actions: [
Padding(
padding: const EdgeInsets.only(right: 150.0,top: 5.0),
child: DropdownButton(
value:_selectedIndex,
items:const [
DropdownMenuItem(
child: Text("Chitwan"),
value: 1,
),
DropdownMenuItem(
child: Text("Kathmandu"),
value: 2,
),
DropdownMenuItem(
child: Text("Pokhara"),
value: 3,
),
DropdownMenuItem(
child: Text("Butwal"),
value: 4,
),
DropdownMenuItem(
child: Text("Hetauda"),
value: 5,
),
],
onChanged: onTapped,
),
),
// PopupMenuButton(itemBuilder: (BuildContext context){
// return[
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Chitwan"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Kathmandu"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Pokhara"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Butwal"),
// )
// ),
// PopupMenuItem(child: InkWell(
// onTap: (){},
// child: Text("Hetauda"),
// )
// ),
// ];
// }),
IconButton(onPressed: (){
Provider.of<AuthProvider>(context,listen: false).logout(context);
}, icon: const Icon(Icons.person,color: Colors.black,)),
IconButton(onPressed: (){}, icon: const Icon(Icons.shopping_cart_outlined,color: Colors.black,)),
],
),
// drawer: AppDrawer(),
// body:BottomNavigation()
body: SingleChildScrollView(
scrollDirection: Axis.vertical,
child: Column(
children: [
Form(
child: Padding(
padding: const EdgeInsets.only(left:2.0),
child: Container(
height: 45.0,
width: 380.0,
decoration:const BoxDecoration(
color: Color(0xFFF2F3F7),
),
child: TextFormField(
decoration: const InputDecoration(
border: OutlineInputBorder(
borderSide: BorderSide.none,
),
icon: Padding(
padding: EdgeInsets.only(left: 5.0),
child: Icon(Icons.search),
),
hintText:'Hi, how can i help you?',
hintStyle: TextStyle(fontSize: 14.0)
),
),
),
),
),
// const SizedBox(height: 10.0),
AnimatedContainer(
height:_selected?220:140,
decoration:const BoxDecoration(
borderRadius: BorderRadius.only(bottomLeft: Radius.circular(40.0),bottomRight: Radius.circular(20.0)),
color: Colors.white,
),
duration: const Duration(seconds: 1),
curve: Curves.fastOutSlowIn,
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
const Expanded(
child: SizedBox(
height:100.0,
child: Padding(
padding: EdgeInsets.only(top: 20.0),
child: CategoryGrid(),
),
),
),
IconButton(onPressed:(){
changeAnimatedContainerHeight(_selected);
}, icon:Icon(_selected?Icons.expand_less:Icons.expand_more),color:Colors.black12,iconSize: 30.0,),
],
),
),
const SizedBox(height: 10.0),
CarouselSlider(
items:imageList.map((e) =>ClipRRect(
borderRadius: BorderRadius.circular(8.0),
child: Stack(
fit: StackFit.expand,
children: [
Padding(
padding: const EdgeInsets.all(15.0),
child: Image.network(e,fit: BoxFit.cover),
)
],
),
) ).toList()
, options: CarouselOptions(viewportFraction: 1,height: 140.0,autoPlay: true,autoPlayAnimationDuration: const Duration(milliseconds: 800),),),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Today's Special",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:150.0,
child: Padding(
padding: EdgeInsets.only(left: 0),
child:TodaySpecialGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Our Partners",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:180.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:OurPartnersGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Our Hotels",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:180.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:OurHotelGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("New Products",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:180.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:NewProductGrid(),
),
),
)
],
),
const SizedBox(height: 10.0),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:[
const Padding(
padding:EdgeInsets.only(right: 0.0),
child: Text("Vegetables",style: TextStyle(fontWeight: FontWeight.bold),),
),
Padding(
padding: const EdgeInsets.only(left: 170.0),
child: GestureDetector(onTap: (){},child: const Text("More",style: TextStyle(color: Color(0xFFE10A35),fontWeight: FontWeight.w600),)),
),
const Padding(
padding: EdgeInsets.only(right: 20.0),
child: Icon(Icons.chevron_right,color: Color(0xFFE10A35),),
),
],
),
const SizedBox(height: 10.0),
Row(
children: const [
Expanded(
child: SizedBox(
height:500.0,
child: Padding(
padding: EdgeInsets.only(left: 8.0),
child:VegetableGrid(),
),
),
)
],
),
// const BottomNavigation()
]),
),
),
);
}
}
我认为这可能会解决您的问题：
extractedData.forEach((element){
loadedProduct.add(CategoryModel(
id:element['id'],
image:element!['images'],
name:element['name'],
));
如果您还有其他问题，请告诉我。