Map user = {};
Future<void> getUser(String idProfile) async {
final response = await ac.getItem("/v2/users/:0", [idProfile]);
if (response.statusCode >= 200 && response.statusCode < 300) {
setState(() {
user = json.decode(response.body);
print(user);
});
}
}
#override
void initState() {
super.initState();
getUser(getCurrentUser());
print(user);
}
With the first print, it returns me the user. However, at the second doesn't. I need to get the user information. How could I do it?
getUser is a future method, you need to wait until it fetches data from API. While you are using StatefulWidget , you can show landing indication while it fetch data from API.
If it is inside Column widget,
if (user.isEmpty) Text("fetching data")
else LoadDataWidget(),
Also you can use ternary operator.
Map user = {};
//Return a user from the function
Future<Map<String, dynamic>> getUser(String idProfile) async {
final response = await ac.getItem("/v2/users/:0", [idProfile]);
if (response.statusCode >= 200 && response.statusCode < 300) {
user = json.decode(response.body) as Map<String, dynamic>;
return user
}
else {
throw Exception();
}
}
// Set the user value in initstate
#override
void initState() {
super.initState();
user = getUser(getCurrentUser());
print(user);
}
Related
I'm trying to get datas from api and add them a list. But at this moment, I see datas i got but I can't get it out of the function. What should i do?
function
List<dynamic> xxx = [];
#override
void initState() {
super.initState();
Future<List<dynamic>> fetchCompanies(List<dynamic> datas) async {
var response = await Dio().get(CompaniesPath().url);
if (response.statusCode == HttpStatus.ok) {
Map<String, dynamic> company = jsonDecode(response.data);
for (int i = 0; i < company['Data'].length; i++) {
datas.add(company['Data'][i]);
}
//print(datas); //=> I see datas here
} else {
throw Exception();
}
return datas;
}
print(fetchCompanies(xxx));
}
When I run print(fetchCompanies(xxx)); I got "Instance of 'Future<List<dynamic>>'". How can i get data inside fetchCompanies to my xxx list?
You're trying to print future instance of List that's why you got
Instance of Future<List>
You have to wait until function finish executing.
Catch here is you can't call wait in initState() so you have to use .then method
try this:
fetchCompanies(xxx)
.then((result) {
print("result: $result");
});
It should already work fine like it is. But you probably want to call a setState to refresh the page. Try this:
#override
void initState() {
super.initState();
Future<List<dynamic>> fetchCompanies(List<dynamic> datas) async {
var response = await Dio().get(CompaniesPath().url);
if (response.statusCode == HttpStatus.ok) {
Map<String, dynamic> company = jsonDecode(response.data);
for (int i = 0; i < company['Data'].length; i++) {
datas.add(company['Data'][i]);
}
//print(datas); //=> I see datas here
setState(() {}); // added this
} else {
throw Exception();
}
return datas;
}
print(fetchCompanies(xxx));
}
In my code I want fetch data to backend without show in ui. Data getting from API, andaslo for that I use model class that same model and API call I used to fetch data and show in UI. That's work without any errors.But in this page I want get doctor_in vale is true or false from that same model and API call method.
model class
class DataDoctor {
String appId;
String channelName;
String receiver_name;
bool doctor_in;
DataDoctor(
{required this.appId,
required this.channelName,
required this.receiver_name,
required this.doctor_in});
factory DataDoctor.fromJson(Map<String, dynamic> json) {
return DataDoctor(
appId: json['appId'] == null ? null : json['appId'],
channelName: json['channelName'] == null ? null : json['channelName'],
receiver_name:
json['receiver_name'] == null ? null : json['receiver_name'],
doctor_in: json['doctor_in'] == null ? null : json['doctor_in'],
);
}
}
using this model I want get doctor_in boolean value
to the getDoctorActive() method
getDoctorActive() method
void getDoctorActive() {
Map<String, dynamic> jsonData =
json.decode(jsonDataAsString) as Map<String, dynamic>;
doctor_in.value = jsonData['doctor_in'].toString(); }
error
How to get data without show in UI in flutter?
API code
import 'dart:convert';
import 'package:http/http.dart';
import '../model/appIdModel.dart';
class ApiService {
loadData(String channelName) async {
final String url ='https://jsonplaceholder.typicode.com/posts/1=$channelName';
Future<List<Data>> getData() async {
Response response = await get(Uri.parse(url));
if (response.statusCode == 2000) {
Map<String, dynamic> json = jsonDecode(response.body);
List<dynamic> body = json['data'];
List<Data> datas = body.map((dynamic item) => Data.fromJson(item).toList();
return datas;
} else {
throw ('cannot fetch data');
}
}
}
}
initState
Timer? timer;
bool doctor_in = false;
#override
void initState() {
super.initState();
getDoctorActive();
timer =
Timer.periodic(Duration(seconds: 15), (Timer t) => checkDoctorActive());
}
checkDoctorActive
Future<void> checkDoctorActive() async {
if (doctor_in == true) {
future = client.getData(widget.channelName);
}
}
errors
API call
If you want to periodically fetch data in the background without updating the UI, you can create a class for that purpose, like this
class DoctorCheck{
Future<bool> isDoctorActive(String channelName) async {
// do the api call here as shown in the line below
// var jsonResponse = await client.getData(widget.channelName)
return Data.fromJson(jsonResponse).doctor_in == true;
}
}
And call it wherever you want, like this
bool isDoctorActive = await DoctorCheck().isDoctorActive(channelName);
It will return a bool whether the doctor is active or not.
Put it in a function like this
Future<void> dr() async {
bool isDrActive = await DoctorCheck().isDoctorActive(channelName);
setState(() { doctor_in = isDrActive; });
}
Whenever you call dr(), your variable doctor_in will be updated with the latest value of whether doctor is active or not.
From #rrttrr answer with a change
class DoctorCheck{
Future<bool> isDoctorActive(String channelName) async {
return Data.fromJson(json).doctor_in == true; // Change jsonResponse to json
}
}
So I have a Stateful Widget which has a List variable I want to update from the API call. My issue is that the List is empty even after I do the fetchItems() in the initState().
How can I then update the itemsList with the content of the fetchItems function?
Isnt the function suppose to update itemsList if I use setState().
class _ItemsWidgetState extends State<ItemsWidget> {
List<ItemsModel> itemsList = [];
void initState(){
fetchItems();
}
fetchItems() async {
final response = await http.get(url);
if (response.statusCode == 200) {
final fetchedItems = json.decode(response.body);
for (var item in fetchedItems) {
ItemsModel item = ItemsModel.fromJson(item);
setState(() {
itemsList.add(item);
});
}
} else {
throw Exception('Failed to load items');
}
}
Avoid calling setState inside loops, call it after your task has done.
Always call super.initState and mark initState as overrided
class _ItemsWidgetState extends State<ItemsWidget> {
List<ItemsModel> itemsList = [];
#override
void initState(){
super.initState();
fetchItems();
}
fetchItems() async {
final response = await http.get(url);
if (response.statusCode == 200) {
final fetchedItems = json.decode(response.body);
for (var item in fetchedItems) {
ItemsModel item = ItemsModel.fromJson(item);
/// Remove from setState
itemsList.add(item);
}
/// Tells to Flutter that now something has changed
setState(() {});
} else {
throw Exception('Failed to load items');
}
}
First check fetchedItems is a list type.
class _ItemsWidgetState extends State<ItemsWidget> {
List<ItemsModel> itemsList = [];
void initState(){
fetchItems();
}
fetchItems() async {
final response = await http.get(Uri.parse(url));
if (response.statusCode == 200) {
final fetchedItems = jsonDecode(response.body);
for (var item in fetchedItems) {
ItemsModel item = ItemsModel.fromJson(item);
setState(() {
itemsList.add(item);
});
}
} else {
throw Exception('Failed to load items');
}
}
I have an app contain login and register system ,the system is working correctly.
the problem is I want to keep user logged in by using flutter_session package but don't work.
first I have preloading page contain checking if user is logged in by using functions below :
void gotoTabPae() {
print('ok');
Future.delayed(const Duration(milliseconds: 3000), () {
Navigator.of(context).pushReplacementNamed('tabs');
});
}
void gotoLoginPage() {
print('no');
Future.delayed(const Duration(milliseconds: 3000), () {
Navigator.of(context).pushReplacementNamed('login');
});
}
getuser() async {
var loginedUser;
SharedPreferences preferences = await SharedPreferences.getInstance();
setState(() {
loginedUser= preferences.getString('username');
});
loginedUser != null ? gotoTabPae() : gotoLoginPage();
}
#override
void initState() {
getuser();
super.initState();
}
when I run the app and login then when I restart the app it must go to 'tabs' page ,but the value of username is always null therefore it load login page ,the login function is :
login() async {
var formdata = formLoginKey.currentState;
if (formdata.validate()) {
formdata.save();
var data = {'username': username.text, 'password': password.text};
var url =xxxx/api/controller/users/login_user.php";
var response = await http.post(url, body: data);
var responsebody = jsonDecode(response.body);
if (responsebody['status'] == 'success') {
SharedPreferences pref = await SharedPreferences.getInstance();
pref.setString('username', username.text);
Navigator.of(context).pushReplacementNamed('tabs');
} else {
_showDialog(context, responsebody['status']);
}
} else {
}
}
But in tabs page it is load the session username corret :
getuser() async {
SharedPreferences preferences = await SharedPreferences.getInstance();
var logineduser = preferences.getString('username');
}
#override
void initState() {
getuser();
super.initState();
}
How can I solve this? where is my mistake ?
Your code is running the getuser() method in the initSate() method that too even before the super.initState();. That is the reason the value is no able to load which makes it null. You should use it in the build function.
Your code might look like this:
#override
Widget build(BuildContext context) {
var loginedUser;
loginedUser = await FlutterSession().get('username');
loginedUser != null ? return ClassName()(tabs.dart) : return ClassName()(login.dart);
}
I think that in your login function, pref.setString('username', username.text) is run before the response is received. Can you try this:
http.post(url, body: data).then((response) {
var responsebody = jsonDecode(response.body);
if (responsebody['status'] == 'success') {
SharedPreferences pref = await SharedPreferences.getInstance();
pref.setString('username', username.text);
Navigator.of(context).pushReplacementNamed('tabs');
}
});
and let me know the result?
in my main.dart i have among others those two functions:
Future<void> _fetchMasterData() async {
print("Start fetch");
var jwt = await API.attemptLogIn();
if (jwt != null) {
Map<String, dynamic> answer = jsonDecode(jwt);
if (answer['message'] == 'Auth ok') {
jwtToken = 'Bearer ' + answer['token'];
}
}
await _getArticles();
await _getMainCategories();
await _getIngredients();
await _getArticleIngredients();
print("EndMasterData fetch");
}
And
#override
void initState() {
super.initState();
_fetchMasterData();
}
What i would like to have is to wait in initState till _fethcMasterData is done bevore Widgert build is called.
Is that possible? Many thanks for any help!
Here how I use an async func in initstate;
builder() async {
favoriteDatabase =
await $FloorFavoriteDatabase.databaseBuilder('favorite_database.db')
.build();
setState(() {
favoriteDao = favoriteDatabase.favoriteDao;
});
}
#override
void initState() {
// TODO: implement initState
super.initState();
WidgetsBinding.instance.addPostFrameCallback((_) {
WidgetsBinding.instance.addPostFrameCallback((_) =>
getNamePreferences().then(updateName));
});
builder();
favoriteDao.findAllMoviesAsStreamW();
favoriteDao.findAllMoviesAsStream();
}
Also you can check this mini article too.
It is not possible to await in initState, so when you finish all loading process then you can call SetState method which populate your widget with actual data.
Second solution could be use of futurebuilder or streambuilder where you want to show data but it is only possible if any methods data is not dependent on each other.
Future<void> _fetchMasterData() async {
print("Start fetch");
var jwt = await API.attemptLogIn();
if (jwt != null) {
Map<String, dynamic> answer = jsonDecode(jwt);
if (answer['message'] == 'Auth ok') {
jwtToken = 'Bearer ' + answer['token'];
}
}
await _getArticles();
await _getMainCategories();
await _getIngredients();
await _getArticleIngredients();
print("EndMasterData fetch");
SetState((){}); // added line
}