我实现了添加到购物车功能的项目已成功添加到购物车中，但是当我重新加载 dart 页面时，购物车徽章中的计数未更新而不是计数更新。有人可以帮助我吗？ 这是我的主页。dart
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:badges/badges.dart';
import 'package:hospital/BestDeatProducts/best_deal_product_page.dart';
import 'package:hospital/CartPage/pages/cartPage.dart';
import 'package:hospital/Drawer/dropdown_menu.dart';
import 'package:hospital/FirstSection/carousel.dart';
import 'package:hospital/Drawer/drawercontent.dart';
import 'package:hospital/FloatingActionButton/ConsultWithDoctor/consult_with_doctor.dart';
import 'package:hospital/MedicineCateory/medicine_category_page.dart';
import 'package:hospital/SecondSection/second_page.dart';
import 'package:hospital/ThirdSection/third_page.dart';
import 'package:hospital/TrendingProducts/trending_product_page.dart';
import 'package:hospital/constant.dart';
import 'package:hospital/customApiVariable.dart';
import 'package:provider/provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'No Internet/connectivity_provider.dart';
import 'No Internet/no_internet.dart';
import 'package:http/http.dart' as http;
class HomePage extends StatefulWidget {
@override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
SharedPreferences loginData;
// late String username;
Future getUsername() async {
loginData = await SharedPreferences.getInstance();
setState(() {
// print("uname" + uname.toString());
print("dddpppuu1 : responceData_un" +
loginData.getString('responceData_un').toString());
print("dddpppuu2 : responceData_ue" +
loginData.getString('responceData_ue').toString());
print("dddpppuu3 : responceData_status" +
loginData.getString('responceData_status').toString());
String responceData_uid =
loginData.getString('responceData_uid').toString();
fetchData(responceData_uid);
});
}
var response;
var addToCartApi;
@override
void initState() {
// TODO: implement initState
//
super.initState();
Provider.of<ConnectivityProvider>(context, listen: false).startMonitering();
// for loading
getUsername();
}
fetchData(String argResponceData_uid) async {
var api = Uri.parse(
'$ecommerceBaseUrl/addToCartApi.php?a2rTokenKey=$a2rTokenKey&action=addToCartList&uid=${argResponceData_uid}');
print('cartpage' + api.toString());
response = await http.get(api);
print("Carousel" + response.body);
addToCartApi = jsonDecode(response.body);
print('addToCartApi' + addToCartApi['total'].toString());
print('totalPriceAfterOffer' + totalPriceAfterOffer.toString());
setState(() {});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: kGreen,
title: Text(
"BK Arogyam",
style: TextStyle(fontStyle: FontStyle.italic),
),
actions: [
response != null
? Badge(
position: BadgePosition.topEnd(top: 3, end: 18),
animationDuration: Duration(milliseconds: 300),
animationType: BadgeAnimationType.slide,
badgeContent: Text(
addToCartApi['total']['num'].toString(),
style: TextStyle(color: Colors.white),
),
child: IconButton(
icon: Icon(Icons.shopping_cart),
padding: EdgeInsets.only(right: 30.0),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => Cartpage()),
);
}),
)
: IconButton(
icon: Icon(Icons.shopping_cart),
// onPressed: () => print("open cart"),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => Cartpage()),
);
},
),
DropDownMenu(),
],
),
floatingActionButton: FloatingActionButton(
backgroundColor: kGreen,
onPressed: () => Navigator.push(context,
MaterialPageRoute(builder: (context) => ConsultWithDoctor())),
tooltip: 'Consult With Doctor',
child: Container(
child: Image(
image: AssetImage(
"assets/icons/cwd.png",
),
color: Colors.white,
width: 40,
height: 40,
),
),
),
drawer: Drawer(
child: DrawerContent(),
),
body: pageUI());
}
Widget pageUI() {
return Consumer<ConnectivityProvider>(
builder: (consumerContext, model, child) {
if (model.isOnline != null) {
return model.isOnline
? ListView(
children: [
Carousel(),
SizedBox(
height: 10.0,
),
MedicineCategoryPage(),
SizedBox(
height: 10.0,
),
SecondPage(),
SizedBox(
height: 10.0,
),
ThirdPage(),
SizedBox(
height: 10.0,
),
TrendingProductPage(),
SizedBox(
height: 16.0,
),
BestDealProductPage(),
SizedBox(
height: 10.0,
),
],
)
: NoInternet();
}
return Container(
child: Center(
child: CircularProgressIndicator(),
),
);
},
);
}
}
答案 0 :(得分：1)
您可以使用提供程序包提供的更改通知程序。
并观看有关如何使用的视频，正是为您的用例搜索 YouTube 更改通知程序提供商提供的成长中的开发人员
希望对你有帮助?
答案 1 :(得分：0)
您可以使用 provider(provider: ^5.0.0) 或 Getx(get: ^4.1.4) 来处理这种情况。 GetX 和 Provider 有很多示例可用。
如果您不想使用它们中的任何一个，那么将您的购物车/徽章计数存储到 tempCartCount 变量（例如：int cartCount = 0）并将其设置为徽章计数而不是“addToCartApi['total'][ 'num'].toString()" , 确保在更新/添加购物车项目上设置状态。
这里我提供了一个简单的示例，说明如何更新 appBar 上的计数。
如果您想从任何其他屏幕更改为全局，否则您可以将其设置为本地/私有。
import 'package:badges/badges.dart';
import 'package:flutter/material.dart';
class UpdateCountExample extends StatefulWidget {
@override
_UpdateCountExampleState createState() => _UpdateCountExampleState();
}
int cartCount = 0;
class _UpdateCountExampleState extends State<UpdateCountExample> {
List<String> cartArray = [];
@override
void initState() {
WidgetsBinding.instance!.addPostFrameCallback((timeStamp) {
setState(() {
cartCount = 0;
});
});
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("App Bar"),
actions: [
Padding(
padding: const EdgeInsets.only(right: 18.0, top: 5.0),
child: Badge(
badgeContent: Text(cartCount.toString()),
child: Icon(Icons.add_shopping_cart),
),
)
],
),
body: Container(
alignment: Alignment.center,
padding: EdgeInsets.all(20),
child: Column(
mainAxisSize: MainAxisSize.min,
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Text(
"Add item in cart",
textAlign: TextAlign.center,
style: TextStyle(fontWeight: FontWeight.bold, fontSize: 18, decoration: TextDecoration.none, color: Colors.black),
),
SizedBox(
height: 20,
),
InkWell(
onTap: () {
setState(() {
cartArray.add("value ${cartArray.length}");
cartCount = cartArray.length;
});
},
child: Container(
padding: const EdgeInsets.all(10.0),
color: Colors.amber,
child: Text(
"Add Item",
textAlign: TextAlign.center,
style: TextStyle(fontSize: 15, decoration: TextDecoration.none, color: Colors.black),
),
),
),
Expanded(
child: ListView.builder(
shrinkWrap: true,
itemCount: cartArray.length,
itemBuilder: (context, index) {
return Text(
cartArray[index],
style: TextStyle(fontSize: 20, color: Colors.black),
);
}),
)
],
),
),
);
}
}