【发布时间】：2022-01-19 09:27:26
【问题描述】：
在HomePage.dart 中，我使用http 包和flutter_bloc 获取api 数据用于架构。现在，一旦我获得数据并且如果我选择 HomePage.dart 中的任何项目，那么它将被添加到 MenuCart.dart 中。现在我面临的问题是
- 如果我多次单击同一项目，则会显示重复的
card小部件。 - 在
MenuCart.dart中，我添加了两个按钮+和-，我将数量增加到3，然后我决定删除该项目。现在我回到上一个屏幕，再次添加相同的项目，如果我转到MenuCart.dart，则数量显示4。
我的期望
- 它不应该生成重复的
card，而是数量应该增加。 - 在我删除一个项目并再次添加相同的项目后，数量必须显示
1。
在HomePage.dart 中，由于冗长，我显示的代码数量非常有限，但我添加了 bloc 和 MenuCart.dart 的代码。
HomePage.dart
GestureDetector(
onTap: () {
BlocProvider.of<MenuCartBloc>(context)
.add(AddToCart(data[index])); // Here adding an item in MenuCart
},
child: Container(
child: Center(
child: Padding(
padding: const EdgeInsets.all(4.5)
child: Text('ADD'),
),
),
),
);
DishMenuTypesId.dart（模型）
class DishMenuTypesIdData {
String? id;
int? status;
int? quantity;
String? dishPrice;
String? photo;
DishMenuTypesIdData({
this.id,
this.status,
this.quantity = 1,
this.dishPrice,
this.photo,
});
DishMenuTypesIdData.fromJson(Map<String, dynamic> json) {
id = json['id']?.toString();
status = json['status']?.toInt();
quantity = 1;
dishPrice = json['dish_price']?.toString();
photo = json['photo']?.toString();
}
Map<String, dynamic> toJson() {
final data = <String, dynamic>{};
data['id'] = id;
data['status'] = status;
data["quantity"] = quantity;
data['dish_price'] = dishPrice;
data['photo'] = photo;
return data;
}
}
class DishMenuTypesId {
String? message;
List<DishMenuTypesIdData?>? data;
DishMenuTypesId({
this.message,
this.data,
});
DishMenuTypesId.fromJson(Map<String, dynamic> json) {
message = json['message']?.toString();
if (json['data'] != null) {
final v = json['data'];
final arr0 = <DishMenuTypesIdData>[];
v.forEach((v) {
arr0.add(DishMenuTypesIdData.fromJson(v));
});
this.data = arr0;
}
}
Map<String, dynamic> toJson() {
final data = <String, dynamic>{};
data['message'] = message;
if (this.data != null) {
final v = this.data;
final arr0 = [];
v!.forEach((v) {
arr0.add(v!.toJson());
});
data['data'] = arr0;
}
return data;
}
}
MenuCartBloc.dart
class MenuCartBloc extends Bloc<MenuCartEvent, MenuCartState> {
MenuCartBloc() : super(MenuLoaded([]));
List<DishMenuTypesIdData> cart = [];
@override
Stream<MenuCartState> mapEventToState(
MenuCartEvent event,
) async* {
yield MenuLoading();
try {
if (event is AddToCart) {
final itemExist = cart.where((e) => e.id == event.dish.id);
if (itemExist.isNotEmpty) {
print("Not Empty"); // Here i am expecting to show qty 2 if i click an item more than 1 time
} else {
print("Empty");
cart.add(event.dish);
}
} else if (event is DeleteToCart) {
cart.remove(event.dish);
} else if (event is ClearAllCart) {
cart = [];
}
yield MenuLoaded(cart);
} catch (e) {
yield MenuFailed(e.toString());
}
}
}
MenuCartEvent.dart
abstract class MenuCartEvent {}
class AddToCart extends MenuCartEvent {
late final DishMenuTypesIdData dish;
AddToCart(this.dish);
}
class DeleteToCart extends MenuCartEvent {
late final DishMenuTypesIdData dish;
DeleteToCart(this.dish);
}
class ClearAllCart extends MenuCartEvent {}
MenuCartState.dart
abstract class MenuCartState {}
class MenuLoading extends MenuCartState {}
class MenuLoaded extends MenuCartState {
final List<DishMenuTypesIdData> cart;
MenuLoaded(this.cart);
}
class MenuFailed extends MenuCartState {
final String message;
MenuFailed(this.message);
}
MenuCart.dart
Widget build(BuildContext context) {
var height = MediaQuery.of(context).size.height;
var width = MediaQuery.of(context).size.width;
var lang = translator.activeLanguageCode;
return Container(
child: Padding(
padding: const EdgeInsets.only(top: 20.0, left: 10.0, right: 10.0),
child: BlocBuilder<MenuCartBloc, MenuCartState>(
builder: (context, state) {
DishMenuTypesIdData _cart = DishMenuTypesIdData();
if (state is MenuLoading) {
return PlatformCircularProgressIndicator();
} else if (state is MenuLoaded) {
return SingleChildScrollView(
child: Column(
children: [
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text(
'Your Reservation Details'.tr(),
style: TextStyle(
color: TuxedoColor.blackColor,
fontSize: lang == "en" ? 14.0 : 15.0,
fontFamily: lang == "en"
? 'OpenSansBold'
: 'ArabicSemiBold'),
),
GestureDetector(
onTap: () {
BlocProvider.of<MenuCartBloc>(context)
.add(ClearAllCart());
},
child: Row(
children: [
Icon(
Icons.close,
color: TuxedoColor.redColor,
size: 15.0,
),
Text(
'Clear All'.tr(),
style: TextStyle(
color: TuxedoColor.redColor,
fontSize: 12.0,
fontFamily: lang == "en"
? 'OpenSansRegular'
: 'ArabicLight'),
),
],
),
)
],
),
SizedBox(
height: 25.0,
),
Container(
height: height * 0.3,
child: ListView.builder(
shrinkWrap: true,
scrollDirection: Axis.vertical,
itemCount: state.cart.length,
itemBuilder: (BuildContext context, int index) {
_cart = state.cart[index];
return Dismissible(
key: UniqueKey(),
background: Container(
alignment: AlignmentDirectional.centerEnd,
color: TuxedoColor.redBrightColor,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Icon(
Icons.delete,
color: TuxedoColor.whiteColor,
),
),
),
onDismissed: (direction) {
BlocProvider.of<MenuCartBloc>(context)
.add(DeleteToCart(_cart));
setState(() {
state.cart.removeAt(index);
});
},
direction: DismissDirection.endToStart,
child: Card(
child: Row(
children: [
Stack(
children: [
ClipRRect(
borderRadius:
BorderRadius.circular(10.0),
child: CachedNetworkImage(
imageUrl:
_cart.photo!,
placeholder: (context, url) => Center(
child:
PlatformCircularProgressIndicator()),
errorWidget:
(context, url, error) =>
Icon(Icons.error),
width: width * 0.25,
height: height * 0.1,
fit: BoxFit.fill,
),
),
Positioned(
bottom: 0,
right: 0,
child: Container(
decoration: BoxDecoration(
color: TuxedoColor.redColor,
borderRadius: lang == "en"
? BorderRadius.only(
bottomRight:
Radius.circular(
10),
)
: BorderRadius.only(
bottomLeft:
Radius.circular(
10),
)),
height: 25.0,
width: 45.0,
child: Padding(
padding: const EdgeInsets.only(
left: 3.0, right: 3.0),
child: FittedBox(
fit: BoxFit.fitWidth,
child: Text(
'${_cart.dishPrice!} \SR',
style: TextStyle(
color: TuxedoColor
.whiteColor,
fontFamily: lang == "en"
? 'OpenSansSemiBold'
: 'ArabicSemiBold'),
),
),
),
),
)
],
),
Padding(
padding:
const EdgeInsets.only(left: 10.0),
child: Column(
children: [
Container(
width: width * 0.6,
child: Row(
mainAxisAlignment:
MainAxisAlignment
.spaceBetween,
children: [
Container(
height: 25.0,
child: Row(
children: [
MaterialButton(
color: TuxedoColor
.redColor,
shape: CircleBorder(),
onPressed: () {
setState(() {
var minus = state
.cart[index]
.quantity;
if (minus !=
null) {
minus--;
state
.cart[index]
.quantity = minus;
}
});
},
child: Text(
'-',
style: TextStyle(
color: Colors
.white,
fontSize: 20),
),
),
Text(_cart.quantity
.toString()),
MaterialButton(
color: TuxedoColor
.redColor,
shape: CircleBorder(),
onPressed: () {
setState(() {
var add = state
.cart[index]
.quantity;
if (add != null) {
add++;
state
.cart[index]
.quantity = add;
}
});
},
child: Text(
'+',
style: TextStyle(
color: Colors
.white,
fontSize: 20),
),
),
],
),
),
GestureDetector(
onTap: () {
BlocProvider.of<
MenuCartBloc>(
context)
.add(DeleteToCart(
state.cart[
index]));
},
child: Icon(
Icons.delete,
color:
TuxedoColor.redColor,
),
)
],
),
),
SizedBox(
height: 15.0,
)
],
),
),
],
),
),
);
}),
),
],
),
);
} else if (state is MenuFailed) {
return Center(child: Text(state.message));
}
return Container();
},
)),
);
}
【问题讨论】：
标签： flutter http dart flutter-bloc