如何解决Flutter State对象未在changeNotifierProvider中更新
我做了一个changenotifierprovider，然后更改了其中的一些数据，当我打印它时，它显示了更新的数据。
但是，当我尝试获取相同的数据对象时，它显示的是存储在其中的先前版本，而不是最新的更新数据。
我还使用了notifyListeners（）;在其中进行更新，以便可以在所有正在使用数据的地方进行更新，但是不会发生。
data.dart文件：（提供者）
import 'dart:convert';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import '../Desktop/data_format.dart';
import '../auth/auth-api.dart' as auth;
class DataProvider with ChangeNotifier {
bool _subscribed = false;
List<DataTemplate> _data = [];
List<CategoryTemplate> _categorydata = [];
List<CategoryTemplate> get categorylist {
return [..._categorydata];
}
List<DataTemplate> get datalist {
print("New Data: $_data _subscribed = $_subscribed");
return [..._data];
}
bool get subscription {
return _subscribed;
}
Future<void> checkSubscription() async {
print("Checking Subscription");
try {
var _response = await http.get(auth.urlallusers);
var _extracteddata = jsonDecode(_response.body) as Map<String,dynamic>;
if (_extracteddata == null) {
return;
} else {
print("You User id is subscribed");
_subscribed = true;
}
} catch (error) {
print("Not Subscribed");
throw (error);
}
notifyListeners();
}
Future<bool> fetchData({bool force = false}) async {
if (_data.length == 0 || force == true) {
_data.clear();
String urldata;
await checkSubscription();
_subscribed ? urldata = auth.urldata : urldata = auth.urldemo;
try {
_subscribed ? print("Fetching data") : print("Fetching demo");
var _response = await http.get(urldata);
var _extracteddata = jsonDecode(_response.body) as Map<String,dynamic>;
List<DataTemplate> _loadeddata = [];
int itr = 0;
List<CategoryTemplate> _categoryloadeddata = [];
_extracteddata.forEach((category,subcategory) {
var _newdata = CategoryTemplate(
id: itr,category: category,subcategory: [],);
Map<String,dynamic> _subcategorylist = subcategory;
_subcategorylist.forEach((subcategoryname,names) {
_newdata.subcategory.add(subcategoryname);
Map<String,dynamic> name = names;
name.forEach((nametext,value) {
_loadeddata.add(
DataTemplate(
id: itr,subcategory: subcategoryname,name: nametext,address: _subscribed ? value['address'] : "demo",email: _subscribed ? value['mail'] : "demo",phonenumber: _subscribed ? value['mob'] : ["demo"].toList(),),);
itr++;
});
});
_categoryloadeddata.add(_newdata);
});
_loadeddata.forEach((element) {
_data.add(element);
});
_categoryloadeddata.forEach((element) {
_categorydata.add(element);
});
notifyListeners();
print("Data: $_data");
return false;
} catch (error) {
print("Error has occured during fetching data/demo");
throw (error);
}
} else {
print("All people data has already been fetched");
return false;
}
}
void addCategory() {
// _categorylist.add(value);
notifyListeners();
}
}
categorypage.dart文件：（正在调用数据的地方）
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../Desktop/data_format.dart';
import '../providers/data.dart';
import '../Desktop/categorytiles.dart';
import 'datatiles.dart';
import '../providers/category.dart';
class CategoryPage extends StatefulWidget {
@override
_CategoryPageState createState() => _CategoryPageState();
}
class _CategoryPageState extends State<CategoryPage> {
bool _pagecategory = true;
DataProvider _dataProvider;
List<DataTemplate> _filteredpeople;
List<CategoryTemplate> _categorylist;
bool _isLoadingCategory = true;
bool _isLoadingData = true;
bool _isInit = true;
@override
void didChangeDependencies() {
super.didChangeDependencies();
print("_isInit = $_isInit");
print("Is loading Category: $_isLoadingCategory");
if (_isInit) {
fetchData();
}
_dataProvider = Provider.of<DataProvider>(context);
setState(() {
_filteredpeople = _dataProvider.datalist;
_categorylist = _dataProvider.categorylist;
});
print("_filteredpeople = $_filteredpeople");
_isInit = false;
}
void fetchData() {
Provider.of<CategoryProvider>(context).fetchCategoryData().then((check) => {
setState(() {
_isLoadingCategory = check;
}),print("Is loading Category: $_isLoadingCategory"),});
Provider.of<DataProvider>(context).fetchData().then((check) => {
setState(() {
_isLoadingData = check;
}),print("Is loading Data: $_isLoadingData"),});
}
void _togglePage(bool _switchme) {
setState(
() {
_pagecategory = _switchme;
},);
}
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Color(0xffd4e6f1),floatingActionButtonLocation: FloatingActionButtonLocation.endFloat,floatingActionButton: FloatingActionButton(
elevation: 3,backgroundColor: Color(0xff1b4f72),child: Icon(
Icons.arrow_back_ios,color: Colors.white,size: 20,onPressed: () {
Navigator.pop(context);
},body: SafeArea(
child: Container(
margin: EdgeInsets.only(top: 20),child: Column(
children: <Widget>[
//SearchTab
Card(
shadowColor: Colors.blue[300],margin: EdgeInsets.symmetric(vertical: 5,horizontal: 30),shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(40)),elevation: 4,child: Container(
margin: EdgeInsets.symmetric(horizontal: 25,vertical: 10),padding: EdgeInsets.all(10),child: TextField(
cursorColor: Color(0xff5499c7),textAlign: TextAlign.justify,style: TextStyle(
color: Color(0xdd1a5276),fontFamily: "roboto",decoration: InputDecoration(
focusColor: Colors.black,enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Color(0xff5499c7),width: 2,focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Color(0xff5499c7),suffixIcon: Container(
child: IconButton(
icon: Icon(
Icons.search,color: Color(0xff5499c7),onPressed: () {},hintText:
_pagecategory ? "Search Category" : "Search People",hintStyle: TextStyle(
fontFamily: "roboto",color: Color(0x881a5276),onChanged: (text) {
setState(() {
_pagecategory
? _categorylist = _dataProvider.categorylist
.where((u) => u.category
.toLowerCase()
.contains(text.toLowerCase()))
.toList()
: _filteredpeople = _dataProvider.datalist
.where((u) => (u.name
.toLowerCase()
.contains(text.toLowerCase()) ||
u.address
.toLowerCase()
.contains(text.toLowerCase()) ||
u.subcategory
.toLowerCase()
.contains(text.toLowerCase())))
.toList();
});
},Padding(
padding: const EdgeInsets.all(10.0),child: Row(
mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[
FlatButton(
highlightColor: Colors.transparent,splashColor: Colors.transparent,color: _pagecategory
? Color(0xff5499c7)
: Colors.transparent,child: Text(
"Category",style: TextStyle(
fontFamily: "roboto",color:
_pagecategory ? Colors.white : Color(0xff5499c7),onPressed: () {
_togglePage(true);
},FlatButton(
highlightColor: Colors.transparent,color: _pagecategory
? Colors.transparent
: Color(0xff5499c7),child: Text(
"All People",color:
_pagecategory ? Color(0xff5499c7) : Colors.white,onPressed: () {
_togglePage(false);
},],// data region
Expanded(
child: GestureDetector(
onHorizontalDragUpdate: (details) {
details.delta.dx > 0
?
//Right Swipe
_togglePage(true)
: //Left Swipe
_togglePage(false);
},child: _pagecategory
? _isLoadingCategory
? Center(
child: CircularProgressIndicator(),)
: ListView.builder(
padding: EdgeInsets.all(10),itemCount: _categorylist.length,itemBuilder: (ctx,index) {
var dataitr = _categorylist[index];
return Container(
key: ValueKey(dataitr.id),child: CategoryTile(
category: dataitr.category,subcategory: dataitr.subcategory),);
},)
: _isLoadingData
? Center(
child: CircularProgressIndicator(),itemCount: _filteredpeople.length,index) {
var dataitr = _filteredpeople[index];
return Container(
key: ValueKey(_filteredpeople[index].id),child: DataTile(
name: dataitr.name,category: dataitr.category,subcategory: dataitr.subcategory,address: dataitr.address,email: dataitr.email,phonenumber: dataitr.phonenumber),)
],);
}
}
payment.dart：文件（付款成功后数据会更新）
import 'dart:convert';
import 'package:ShowWorld/models/listed_data.dart';
import 'package:ShowWorld/providers/data.dart';
import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:http/http.dart' as http;
import 'package:razorpay_flutter/razorpay_flutter.dart';
import '../auth/auth-api.dart' as auth;
class PaymentProvider with ChangeNotifier {
bool _notsubscribed = true;
Razorpay _razorpaySubscription = Razorpay();
@override
void dispose() {
super.dispose();
_razorpaySubscription.clear();
_razorpayListYourself.clear();
}
bool get subscriptionstatus {
return _notsubscribed;
}
void httpsubscribed() async {
var _extract = await http.get(auth.urlallusers);
_notsubscribed = jsonDecode(_extract.body) == null;
notifyListeners();
}
void _handlePaymentSuccess(PaymentSuccessResponse response) {
print("Payment Successful");
_notsubscribed = false;
notifyListeners();
Map<String,String> data = {
'mob': '${auth.user.phoneNumber}','timestamp': '${DateTime.now().toIso8601String()}',};
try {
sendhttpRequest(data);
Fluttertoast.showToast(
msg: "Payment Successful",backgroundColor: Colors.green,);
} catch (e) {
throw (e);
}
}
void sendhttpRequest(Map<String,String> data) async {
try {
await http
.patch(
auth.urlallusers,headers: {"Accept": "application/json"},body: jsonEncode(data),)
.then(
(value) async {
print("User Added to Subscription List");
await DataProvider().fetchData(force: true);
notifyListeners();
},);
} catch (e) {
throw (e);
}
}
void _handlePaymentError(PaymentFailureResponse response) {
print("Payment failed");
Fluttertoast.showToast(
msg: "Payment Failed",backgroundColor: Colors.red,);
}
void _handleExternalWallet(ExternalWalletResponse response) {
print("Choosing Wallet");
}
void makePayment(double price) {
_razorpaySubscription.on(
Razorpay.EVENT_PAYMENT_SUCCESS,_handlePaymentSuccess);
_razorpaySubscription.on(Razorpay.EVENT_PAYMENT_ERROR,_handlePaymentError);
_razorpaySubscription.on(
Razorpay.EVENT_EXTERNAL_WALLET,_handleExternalWallet);
var options = {
'key': '${auth.razorpaykey}','amount': price * 100,'name': 'Show World Subscription','description': 'Subscription','prefill': {
'contact': '${auth.user.phoneNumber}',}
};
try {
_razorpaySubscription.open(options);
notifyListeners();
} catch (e) {
throw (e);
}
}
调试控制台：
User Added to Subscription List
I/flutter (15578): Checking Subscription
W/libEGL (15578): EGLNativeWindowType 0x9faf8b08 disconnect failed
D/ViewRootImpl@daf6f43[Toast](15578): dispatchDetachedFromWindow
D/InputTransport(15578): Input channel destroyed: '41874fb',fd=215
I/flutter (15578): You User id is subscribed
I/flutter (15578): Fetching data
D/ViewRootImpl@6e7f972[MainActivity](15578): ViewPostIme key 0
D/ViewRootImpl@6e7f972[MainActivity](15578): ViewPostIme key 1
I/flutter (15578): Data: [Instance of 'DataTemplate',Instance of 'DataTemplate',Instance of 'DataTempl
ate',Instance of 'DataT
emplate',Instance of 'D
ataTemplate',Instance o
f 'DataTemplate',Instan
ce of 'DataTemplate',In
stance of 'DataTemplate',Instan
ce
D/ViewRootImpl@6e7f972[MainActivity](15578): ViewPostIme pointer 0
D/ViewRootImpl@6e7f972[MainActivity](15578): ViewPostIme pointer 1
I/flutter (15578): _isInit = true
I/flutter (15578): Is loading Category: true
I/flutter (15578): Category data has already been fetched
I/flutter (15578): All people data has already been fetched
I/flutter (15578): New Data: [Instance of 'DataTemplate',Instance of 'DataTemplate'] _subscribed = fals
e
I/flutter (15578): _filteredpeople = [Instance of 'DataTemplate',Instance of 'DataTemplate']
I/flutter (15578): Is loading Category: false
I/flutter (15578): Is loading Data: false
正如您在调试控制台中所看到的，“新数据：”的项目数少于数据：（因为未更新）
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 dio@foxmail.com 举报，一经查实，本站将立刻删除。