I'm trying to find out if there is a specific user in the bank. I intend to get this user's information and give them the option to update their information or not.
For that, I'm bringing his identifier from the previous page and trying to get his data like this:
Future<List>? _list;
.
.
#override
void initState() {
_list = widget.userServices.searchUser(widget.cpf);
super.initState();
}
This returns me a json correctly.
This is my service to get a user's data:
searchUser(cpf) async {
try {
final response = await http.get(
Uri.parse(BaseUrl.baseUrl + 'api/user/buscaProdutorPorCPF/$cpf'));
if (response.statusCode == 200) {
return json.decode(response.body);
} else {
throw Exception("Error");
}
} catch (e) {
throw Exception(e.toString());
}
}
Finally, I'm trying to display the information with this example code:
#override
#override
Widget build(BuildContext context) {
return FutureBuilder(
future: _list,
builder: (context, snapshot) {
print(snapshot);
if (snapshot.hasData)
return _buildBody(snapshot.data);
else if (snapshot.hasError)
return _buildErrorPage(snapshot.error);
else
return _buildLoadingPage();
},
);
}
Widget _buildBody(List userList) => Scaffold(
appBar: AppBar(
title: Text('Employee Title = ${userList[0].nome}'),
),
body: ListView.builder(
itemCount: userList.length,
itemBuilder: (context, index) {
return ListTile(
title: Text(userList[index].email!),
);
},
),
);
Widget _buildErrorPage(error) => Material(
child: Center(
child: Text("ERROR: $error"),
),
);
Widget _buildLoadingPage() => Material(
child: Center(
child: CircularProgressIndicator(),
),
);
But I'm getting the following error:
I appreciate if anyone can help me analyze this error!
I think modifying the code like this:
return FutureBuilder(
//rest of code
);
and
Widget _buildBody(List userList) => //rest of code
will resolve the problem.
At first, when i started writing my calls to get data from firestore, it worked. But when i tried writing more docs to my collection, it failed to bring data for the docs i recently added. Then, when i deleted the first one i added, i stopped receiveing data from firestore all together. I have tried several methods, but have all ended in failure.
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
class collect extends StatefulWidget {
#override
_collectState createState() => _collectState();
}
class _collectState extends State<collect>
{
Future _data;
void initState()
{
super.initState();
_data = getStuff();
}
Future getStuff()
async {
var firestore = FirebaseFirestore.instance;
QuerySnapshot qn = await firestore.collection("buses").get();
return qn.docs;
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: FutureBuilder(
future: _data,
builder: (_, snapshot)
{
if(snapshot.connectionState == ConnectionState.waiting)
{
return Center(
child:Text("Loading")
);
}
else if(snapshot.connectionState == ConnectionState.done)
{
return ListView.builder(itemCount: snapshot.data.length,itemBuilder:(_, index)
{
return Container(
child: ListTile(
title: Text(snapshot.data[index].data()["name"].toString()),
subtitle: Text(snapshot.data[index].data()["price"].toString()),
),
);
});
}
},
),
);
}
}
```
Define your database call as,
Future getStuff() async {
var docs;
await FirebaseFirestore.instance
.collection("buses")
.get()
.then((querySnapshot) {
docs = querySnapshot.docs;
});
return docs;
}
Then use the FutureBuilder in the build() function as,
return Scaffold(
body: Center(
child: FutureBuilder<dynamic>(
future: getStuff(),
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
if (snapshot.hasData) {
return ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (_, index) {
return Container(
child: ListTile(
title: Text(
snapshot.data[index].data()["name"].toString()),
subtitle: Text(
snapshot.data[index].data()["price"].toString()),
),
);
});
} else {
return CircularProgressIndicator();
}
},
),
),
);
I wrapped the FutureBuilder inside a Center just for clarity, you may remove that Center widget.
I am trying to show a live count of total documents in an Appbar. I get the right information in my console, but when i try to pass it with an Provider it returns an Instance of 'Future'. Can someone tell why i am getting still an Instence even if i await the result and the result is printed correctly in my console?
this is where i get the Future int and print the result to my console.
class AuthenticationService extends ChangeNotifier {
Future<int> totalJumps(jumpDict) async {
var respectsQuery = _db.collection(jumpDict);
var querySnapshot = await respectsQuery.get();
var result = querySnapshot.docs.length;
print(result);
// notifyListeners();
return result;
}
}
This is were it should show the result as a int in the title of the appBar
class LazyListOnline extends StatefulWidget {
static const String id = 'Lazy_list_online';
#override
_LazyListOnlineState createState() => _LazyListOnlineState();
}
class _LazyListOnlineState extends State<LazyListOnline> {
#override
Widget build(BuildContext context) {
String userDict = Provider.of<AuthenticationService>(context).findJumpDict;
var _firestoreDb =
FirebaseFirestore.instance.collection(userDict).snapshots();
var totalJump = Provider.of<AuthenticationService>(context)
.totalJumps(userDict)
.toString();
return Scaffold(
appBar: AppBar(
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () {
Navigator.popAndPushNamed(context, HomeDrawer.id);
}),
title: Text('totalJumps'),
body: Stack(children: [
Padding(
padding: const EdgeInsets.all(18.0),
child: Container(
decoration: BoxDecoration(),
),
StreamBuilder<QuerySnapshot>(
stream: _firestoreDb,
builder: (context, snapshot) {
if (!snapshot.hasData) return CircularProgressIndicator();
return ListView.builder(
itemCount: snapshot.data.docs.length,
itemBuilder: (context, int index) {
return JumpItem(
snapshot: snapshot.data,
index: index,
);
});
}),
]),
);
}
}
I think you just need to store only the amount of documents as an int in Provider like.
class DocumentData extends ChangeNotifier {
int documentLength;
void setCurrentLengthOfDocuments(int length) {
this. documentLength = length;
notifyListeners();
}
}
Then in StreamBuilder. Every time data has been changed. You just need to update. Regrading to your example be something like.
StreamBuilder<QuerySnapshot>(
stream: _firestoreDb,
builder: (context, snapshot) {
if (!snapshot.hasData) return CircularProgressIndicator();
// Update amount of documents length
Provider.of<DocumentData>(context, listen: false)
.setCurrentLengthOfDocuments(lengthOfCurrentDocuments);
return ListView.builder(
itemCount: snapshot.data.docs.length,
itemBuilder: (context, int index) {
return JumpItem(
snapshot: snapshot.data,
index: index,
);
});
}),
]),
Then when you can get the length of documents every where on this page by just use Consumer widget. Or get the value directly from Provider.
I am retreiving data from cloud firestore and using Future builder and Listview Builder to display the data. But i am getting null values in the Listview builder i.e displaying the CircularProgressIndicator always.Can't figure out the problem.Any solution will be of great help.
The print(values) function prints out: [9,8] successfully
This is the code i implemented:
Future<List> getassignment() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
final name = prefs.getString('orgname') ?? '';
print(name);
var query = FirebaseFirestore.instance.collection('Org').doc(name).collection('Login').doc(FirebaseAuth.instance.currentUser.uid);
query.snapshots().forEach((doc) {
List values = List.from(doc.data()['fields']['class']);
print(values);
return values;
});
}
// void getlist() async{
// await getassignment();
// }
#override
void initState() {
// getlist();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Color(0xFF1976D2),
body: FutureBuilder(
future: getassignment(),
builder: (context,snapshot){
List list = snapshot.data;
if (!snapshot.hasData) {
return Center(child: CircularProgressIndicator());
} else{
return Container(
child: ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (context, position) {
return GestureDetector(
onTap: (){
Navigator.of(context).push(MaterialPageRoute<Null>(
builder: (BuildContext context){
return new SubjectList(
clas: list[position].toString(),
);
}
));
},
child: Card(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Text(list[position].toString(), style: TextStyle(fontSize: 22.0),),
),
),
);
},
),
);
}
},
),
);
}
You are assigning and returning data inside of foreach loop. So that won't return anything.
// try adding await in this line.
var query = await FirebaseFirestore.instance.collection('Org').doc(name).collection('Login').doc(FirebaseAuth.instance.currentUser.uid);
List values = query.snapshots().forEach((doc) => List.from(doc.data()['fields']['class']));
print(values);
return values;
You need to do something like this.
My dashboard code looks like this,
Here I am doing get req in getReport method, I have added the RefreshIndicator in the code which when pulled down inside container should do the refresh, there I am calling my getData(), But I am not getting the refreshed content, I am adding my code below, let me know if anywhere I made a mistake.
below my dashboard.dart
class Window extends StatefulWidget {
#override
_WindowState createState() => _WindowState();
}
class _WindowState extends State<Window> {
Future reportList;
#override
void initState() {
super.initState();
reportList = getReport();
}
Future<void> getReport() async {
http.Response response =
await http.get(reportsListURL, headers: {"token": "$token"});
switch (response.statusCode) {
case 200:
String reportList = response.body;
var collection = json.decode(reportList);
return collection;
case 403:
break;
case 401:
return null;
default:
return 1;
}
}
getRefreshScaffold() {
return Center(
child: RaisedButton(
onPressed: () {
setState(() {
reportList = getReport();
});
},
child: Text('Refresh, Network issues.'),
),
);
}
getDashBody(var data) {
double maxHeight = MediaQuery.of(context).size.height;
return Column(
children: <Widget>[
Container(
height: maxHeight - 800,
),
Container(
margin: new EdgeInsets.all(0.0),
height: maxHeight - 188,
child: new Center(
child: new RefreshIndicator( //here I am adding the RefreshIndicator
onRefresh:getReport, //and calling the getReport() which hits the get api
child: createList(context, data),
),),
),
],
);
}
Widget createList(BuildContext context, var data) {
Widget _listView = ListView.builder(
itemCount: data.length,
itemBuilder: (context, count) {
return createData(context, count, data);
},
);
return _listView;
}
createData(BuildContext context, int count, var data) {
var metrics = data["statistic_cards"].map<Widget>((cardInfo) {
var cardColor = getColorFromHexString(cardInfo["color"]);
if (cardInfo["progress_bar"] != null && cardInfo["progress_bar"]) {
return buildRadialProgressBar(
context: context,
progressPercent: cardInfo["percentage"],
color: cardColor,
count: cardInfo["value"],
title: cardInfo["title"],
);
} else {
return buildSubscriberTile(context, cardInfo, cardColor);
}
}).toList();
var rowMetrics = new List<Widget>();
for (int i = 0; i < metrics.length; i += 2) {
if (i + 2 < metrics.length)
rowMetrics.add(Row(children: metrics.sublist(i, i + 2)));
else
rowMetrics.add(Row(children: [metrics[metrics.length - 1], Spacer()]));
}
return SingleChildScrollView(
child: LimitedBox(
// maxHeight: MediaQuery.of(context).size.height / 1.30,
child: Column(
mainAxisSize: MainAxisSize.max,
mainAxisAlignment: MainAxisAlignment.center,
children: rowMetrics,
),
),
);
}
#override
Widget build(BuildContext context) {
return FutureBuilder(
future: reportList,
builder: (BuildContext context, AsyncSnapshot snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
case ConnectionState.waiting:
case ConnectionState.active:
return Center(
child: CircularProgressIndicator(),
);
case ConnectionState.done:
var data = snapshot.data;
if (snapshot.hasData && !snapshot.hasError) {
return getDashBody(data);
} else if (data == null) {
return Center(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Text("Timeout! Log back in to continue"),
Padding(
padding: EdgeInsets.all(25.0),
),
RaisedButton(
onPressed: () {
setState(() {
token = null;
});
Navigator.of(context).pushReplacement(
CupertinoPageRoute(
builder: (BuildContext context) => LoginPage()),
);
},
child: Text('Login Again!'),
),
],
),
);
} else {
getRefreshScaffold();
}
}
},
);
}
}
Basic Example
Below is a State class of a StatefulWidget, where:
a ListView is wrapped in a RefreshIndicator
numbersList state variable is its data source
onRefresh calls _pullRefresh function to update data & ListView
_pullRefresh is an async function, returning nothing (a Future<void>)
when _pullRefresh's long running data request completes, numbersList member/state variable is updated in a setState() call to rebuild ListView to display new data
import 'package:flutter/material.dart';
import 'dart:math';
class PullRefreshPage extends StatefulWidget {
const PullRefreshPage();
#override
State<PullRefreshPage> createState() => _PullRefreshPageState();
}
class _PullRefreshPageState extends State<PullRefreshPage> {
List<String> numbersList = NumberGenerator().numbers;
#override
Widget build(BuildContext context) {
return Scaffold(
body: RefreshIndicator(
onRefresh: _pullRefresh,
child: ListView.builder(
itemCount: numbersList.length,
itemBuilder: (context, index) {
return ListTile(
title: Text(numbersList[index]),
);
},),
),
);
}
Future<void> _pullRefresh() async {
List<String> freshNumbers = await NumberGenerator().slowNumbers();
setState(() {
numbersList = freshNumbers;
});
// why use freshNumbers var? https://stackoverflow.com/a/52992836/2301224
}
}
class NumberGenerator {
Future<List<String>> slowNumbers() async {
return Future.delayed(const Duration(milliseconds: 1000), () => numbers,);
}
List<String> get numbers => List.generate(5, (index) => number);
String get number => Random().nextInt(99999).toString();
}
Notes
If your async onRefresh function completes very quickly, you may want to add an await Future.delayed(Duration(seconds: 2)); after it, just so the UX is more pleasant.
This gives time for the user to complete a swipe / pull down gesture & for the refresh indicator to render / animate / spin indicating data has been fetched.
FutureBuilder Example
Here's another version of the above State<PullRefreshPage> class using a FutureBuilder, which is common when fetching data from a Database or HTTP source:
class _PullRefreshPageState extends State<PullRefreshPage> {
late Future<List<String>> futureNumbersList;
#override
void initState() {
super.initState();
futureNumbersList = NumberGenerator().slowNumbers();
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: FutureBuilder<List<String>>(
future: futureNumbersList,
builder: (context, snapshot) {
return RefreshIndicator(
child: _listView(snapshot),
onRefresh: _pullRefresh,
);
},
),
);
}
Widget _listView(AsyncSnapshot snapshot) {
if (snapshot.hasData) {
return ListView.builder(
itemCount: snapshot.data.length,
itemBuilder: (context, index) {
return ListTile(
title: Text(snapshot.data[index]),
);
},);
}
else {
return Center(
child: Text('Loading data...'),
);
}
}
Future<void> _pullRefresh() async {
List<String> freshNumbers = await NumberGenerator().slowNumbers();
setState(() {
futureNumbersList = Future.value(freshNumbers);
});
}
}
Notes
slowNumbers() function is the same as in the Basic Example above, but the data is wrapped in a Future.value() since FutureBuilder expects a Future, but setState() should not await async data
according to Rémi, Collin & other Dart/Flutter demigods it's good practice to update Stateful Widget member variables inside setState() (futureNumbersList in FutureBuilder example & numbersList in Basic example), after its long running async data fetch functions have completed.
see https://stackoverflow.com/a/52992836/2301224
if you try to make setState async, you'll get an exception
updating member variables outside of setState and having an empty setState closure, may result in hand-slapping / code analysis warnings in the future
Not sure about futures, but for refresh indicator you must return a void so
Use something like
RefreshIndicator(
onRefresh: () async {
await getData().then((lA) {
if (lA is Future) {
setState(() {
reportList = lA;
});
return;
} else {
setState(() {
//error
});
return;
}
});
return;
},
Try this and let me know!
EDIT:
Well, then just try this inside you refresh method
setState(() {
reportList = getReport();
});
return reportList;
Try this:
onRefresh: () {
setState(() {});
}}
instead of onRefresh:getReport
reportList field is Future which returns its value once. So, when you call getReport again it changes nothing. Actually, more correctly it'll be with Stream and StreamBuilder instead of Future and FutureBuilder. But for this code it can be shortest solution
Easy method: you can just use Pull Down to Refresh Package - https://pub.dev/packages/pull_to_refresh
In Non-scrollable list view, RefreshIndicator does not work, so you have to wrap your widget with Stack for implementing pull down to refresh.
RefreshIndicator(
onRefresh: () {
// Refresh Functionality
},
child: Stack(
children: [
ListView(
padding: EdgeInsets.zero,
shrinkWrap: true,
children: [
SizedBox(
height: MediaQuery.of(context).size.height,
)
],
),
// Your Widget
],
);
),
I am working on a huge project which contains CustomScrollView, NestedScrollView, ListView, etc I tried every answer above and all of the answers use RefreshIndicator from flutter SDK. It doesn't work entirely with my app because I also have horizontal scroll views. So in order to implement it I had to use NestedScrollView on almost every screen. Then I came to know about liquid_pull_to_refresh, applied it to the top widget, and WOLAAH! If you need a separate logic for each screen then use it at the top of each screen but in my case, I'm refreshing the whole project's data.