Im am trying to get userData by id to show userProfile. I create a cubitProfile for this reason but when I go to the profile page the app ProviderNotFoundException(T, context.widget.runtimeType) apears. Can u help me with this error?
Here is my code:
profile
class ProfileScreen extends StatelessWidget {
final String id;
const ProfileScreen({Key? key, required this.id}) : super(key: key);
#override
Widget build(BuildContext context) {
return BlocBuilder<ProfileCubit, ProfileStates>(builder: (context, state) {
var cubit = ProfileCubit.get(context);
return Scaffold(
...
profileCubit
class ProfileCubit extends Cubit<ProfileStates> {
ProfileCubit() : super(ProfileInitState());
static ProfileCubit get(context) => BlocProvider.of(context);
late UserData userData;
void getUserDataById(String id) {
emit(ProfileGetUserLoadingState());
FirebaseFirestore.instance.collection('users').doc(id).get().then((value) {
userData = UserData.fromJson(jsonDecode(jsonEncode(value.data())));
emit(ProfileGetUserSuccessState());
}).catchError((error) {
print(error);
emit(ProfileGetUserErrorState());
});
}
bool isSameUser(String uid) {
if (FirebaseAuth.instance.currentUser!.uid != uid) {
return false;
} else {
return true;
}
}
}
Related
What I am trying to achieve is a small custom state management solution that I believe is powerful enough to run small and large apps. The core is based on the ValueNotifier and ValueListenable concepts in flutter. The data can be accessed anywhere in the app with out context since I am storing the data like this:
class UserData {
static ValueNotifier<DataLoader<User>> userData =
ValueNotifier(DataLoader<User>());
static Future<User> loadUserData() async {
await Future.delayed(const Duration(seconds: 3));
User user = User();
user.age = 23;
user.family = 'Naoushy';
user.name = 'Anass';
return user;
}
}
So by using UserData.userData you can use the data of the user whenever you want. Everything works fine until I encountered a problem of providing a child to my custom data consumer that rebuilds the widget when there is a new event fired. The DataLoader class looks like this:
enum Status { none, hasError, loading, loaded }
class DataLoader<T> {
Status status = Status.none;
T? data;
Object? error;
bool get hasError => error != null;
bool get hasData => data != null;
}
which is very simple. Now the class for consuming the data and rebuilding looks like this:
import 'dart:developer';
import 'package:flutter/material.dart';
import 'package:testing/utils/dataLoader/data_loader.dart';
class DataLoaderUI<T> extends StatefulWidget {
final ValueNotifier<DataLoader<T>> valueNotifier;
final Widget noneStatusUI;
final Widget hasErrorUI;
final Widget loadingUI;
final Widget child;
final Future<T> future;
const DataLoaderUI(
{Key? key,
required this.valueNotifier,
this.noneStatusUI = const Text('Data initialization has not started'),
this.hasErrorUI = const Center(child: Text('Unable to fetch data')),
this.loadingUI = const Center(
child: CircularProgressIndicator(),
),
required this.child,
required this.future})
: super(key: key);
#override
State<DataLoaderUI> createState() => _DataLoaderUIState();
}
class _DataLoaderUIState extends State<DataLoaderUI> {
Future startLoading() async {
widget.valueNotifier.value.status = Status.loading;
widget.valueNotifier.notifyListeners();
try {
var data = await widget.future;
widget.valueNotifier.value.data = data;
widget.valueNotifier.value.status = Status.loaded;
widget.valueNotifier.notifyListeners();
} catch (e) {
log('future error', error: e.toString());
widget.valueNotifier.value.error = e;
widget.valueNotifier.value.status = Status.hasError;
widget.valueNotifier.notifyListeners();
}
}
#override
void initState() {
super.initState();
log('init state launched');
if (!widget.valueNotifier.value.hasData) {
log('reloading or first loading');
startLoading();
}
}
//AsyncSnapshot asyncSnapshot;
#override
Widget build(BuildContext context) {
return ValueListenableBuilder<DataLoader>(
valueListenable: widget.valueNotifier,
builder: (context, dataLoader, ui) {
if (dataLoader.status == Status.none) {
return widget.noneStatusUI;
} else if (dataLoader.status == Status.hasError) {
return widget.hasErrorUI;
} else if (dataLoader.status == Status.loading) {
return widget.loadingUI;
} else {
return widget.child;
}
});
}
}
which is also simple yet very effective. since even if the initState function is relaunched if the data is already fetched the Future will not relaunch.
I am using the class like this:
class TabOne extends StatefulWidget {
static Tab tab = const Tab(
icon: Icon(Icons.upload),
);
const TabOne({Key? key}) : super(key: key);
#override
State<TabOne> createState() => _TabOneState();
}
class _TabOneState extends State<TabOne> {
#override
Widget build(BuildContext context) {
return DataLoaderUI<User>(
valueNotifier: UserData.userData,
future: UserData.loadUserData(),
child: Text(UserData.userData.value.data!.name??'No name'));
}
}
The error is in this line:
Text(UserData.userData.value.data!.name??'No name'));
Null check operator used on a null value
Since I am passing the Text widget as an argument with the data inside it. Flutter is trying to pass it but not able to since there is no data yet so its accessing null values. I tried with a normal string and it works perfectly. I looked at the FutureBuilder widget and they use a kind of builder and also the ValueLisnableBuilder has a builder as an arguement. The problem is that I am not capable of creating something like it for my custom solution. How can I just pass the child that I want without having such an error and without moving the ValueLisnable widget into my direct UI widget?
I have found the solution.
Modify the DataLoaderUI class to this:
import 'dart:developer';
import 'package:flutter/material.dart';
import 'package:testing/utils/dataLoader/data_loader.dart';
class DataLoaderUI<T> extends StatefulWidget {
final ValueNotifier<DataLoader<T>> valueNotifier;
final Widget noneStatusUI;
final Widget hasErrorUI;
final Widget loadingUI;
final Widget Function(T? snapshotData) child;
final Future<T> future;
const DataLoaderUI(
{Key? key,
required this.valueNotifier,
this.noneStatusUI = const Text('Data initialization has not started'),
this.hasErrorUI = const Center(child: Text('Unable to fetch data')),
this.loadingUI = const Center(
child: CircularProgressIndicator(),
),
required this.child,
required this.future})
: super(key: key);
#override
State<DataLoaderUI<T>> createState() => _DataLoaderUIState<T>();
}
class _DataLoaderUIState<T> extends State<DataLoaderUI<T>> {
Future startLoading() async {
widget.valueNotifier.value.status = Status.loading;
widget.valueNotifier.notifyListeners();
try {
var data = await widget.future;
widget.valueNotifier.value.data = data;
widget.valueNotifier.value.status = Status.loaded;
widget.valueNotifier.notifyListeners();
} catch (e) {
log('future error', error: e.toString());
widget.valueNotifier.value.error = e;
widget.valueNotifier.value.status = Status.hasError;
widget.valueNotifier.notifyListeners();
}
}
#override
void initState() {
super.initState();
log('init state launched');
if (!widget.valueNotifier.value.hasData) {
log('reloading or first loading');
startLoading();
}
}
//AsyncSnapshot asyncSnapshot;
#override
Widget build(BuildContext context) {
return ValueListenableBuilder<DataLoader<T>>(
valueListenable: widget.valueNotifier,
builder: (context, dataLoader, ui) {
if (dataLoader.status == Status.none) {
return widget.noneStatusUI;
} else if (dataLoader.status == Status.hasError) {
return widget.hasErrorUI;
} else if (dataLoader.status == Status.loading) {
return widget.loadingUI;
} else {
return widget.child(dataLoader.data);
}
});
}
}
and use it like this:
DataLoaderUI<User>(
valueNotifier: UserData.userData,
future: UserData.loadUserData(),
child: (user) {
return Text(user!.name ?? 'kk');
});
Take a look at my version of the same sort of state management approach here: https://github.com/lukehutch/flutter_reactive_widget
This is a case.
I want to use one TimerWidget for 1+ forms.
And i don`t want to save its state in the Store.
So I created it as an Event, and realized like this.
/// Action
class TimeIsOnAction extends AppAction {
TimeIsOnAction(this.timerCounter);
final int timerCounter;
#override
Future<AppState?> reduce() async {
return state.copyWith(timerCounter: Event(timerCounter));
}
}
/// Widget
class TimerWidget extends StatelessWidget {
const TimerWidget({Key? key, required this.timerCounter}) : super(key: key);
final Event<int> timerCounter;
#override
Widget build(BuildContext context) {
final timer = timerCounter.state ?? 0;
// !!!! Consume or Not ???
timerCounter.consume();
return Center(child: Text('$timer'));
}
}
//////////////////////////////////////////////////////////////////////////////
/// Connector
class TimerWidgetConnector extends StatelessWidget {
const TimerWidgetConnector({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return StoreConnector<AppState, _Vm>(
vm: () => _Factory(),
builder: (context, vm) {
return TimerWidget(
timerCounter: vm.timerCounter,
);
},
);
}
}
///
class _Factory extends AppVmFactory {
#override
_Vm fromStore() {
return _Vm(
timerCounter: state.timerCounter,
);
}
}
///
class _Vm extends Vm {
final Event<int> timerCounter;
_Vm({
required this.timerCounter,
}) : super(equals: [timerCounter]);
}
/// Persisting
#override
Future<void> persistDifference(
{AppState? lastPersistedState, required AppState newState}) async {
if (lastPersistedState == null || lastPersistedState != newState) {
return _safeWrapperS(() async {
final json = newState.toJson();
final s = jsonEncode(json);
_saveString(_appStateKey, s);
return;
});
}
}
/// Applying 1
children: [
const Center(child: TimerWidgetConnector()),
Center(child: Text('$isDarkMode')),
/// Applying 2
10.verticalSpace,
const Center(child: TimerWidgetConnector()),
10.verticalSpace,
But! If i consume event in TimerWidget.build after applying - it works only on one Form
If i don't consume - its state automatically persisted with every event changing.
Is there recipe for that case?
I am saving modal object converted into String to SharedPreference and Killing the app. But when I come back to app SharedPreference has lost the saved data. I am new to flutter. Please help. I want to save my data and kill the app and again retrieve while coming back.
Here is my code
class HomeScreen extends StatefulWidget {
HomeScreen({Key? key}) : super(key: key);
#override
State<HomeScreen> createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> with WidgetsBindingObserver {
List<User> selectedUser = [];
List<User> visibleUser = [];
double screenHeight = 0.0;
static const _keyUser = 'users';
#override
initState() {
super.initState();
WidgetsBinding.instance!.addObserver(this);
getUsersFromSharedPref();
}
Future<void> getUsersFromSharedPref() async {
final pref = await SharedPreferences.getInstance();
setState((){
String savedJson = pref.getString(_keyUser) ?? '';
if(savedJson.length > 0) {
selectedUser = UserApi.getUsersFromSharedPref(savedJson);
}
});
}
Future<void> saveInSharedPref() async {
final pref = await SharedPreferences.getInstance();
String encodedData = UserApi.getStringFromobject(selectedUser);
await pref.setString(_keyUser , encodedData);
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: FutureBuilder<List<User>>(
future: UserApi.getUserLocally(context),
builder: (context, snapshot) {
final allUsers = (selectedUser.isNotEmpty) ? selectedUser : snapshot.data;
visibleUser = (selectedUser.isNotEmpty)?(selectedUser.where((aUser) => (aUser.isDefaultUser)).toList()) : (allUser!.where((aUser) => (aUser.isDefaultUser)).toList());
.
.
.
})
);
}
#override
void dispose() {
super.dispose();
}
#override
void didChangeAppLifecycleState(AppLifecycleState state) {
super.didChangeAppLifecycleState(state);
final isBackground = state == AppLifecycleState.paused;
if (isBackground || (state == AppLifecycleState.inactive ||
state == AppLifecycleState.detached)) {
saveInSharedPref();
}
if(state == AppLifecycleState.resumed){
getUserFromSharedPref();
}
}
}
class UserApi {
static Future<List<User>> getUserLocally(BuildContext context) async {
final assetBundle = DefaultAssetBundle.of(context);
final data = await assetBundle.loadString('assets/data/Users.json');
final body = json.decode(data.toString()).cast<Map<String, dynamic>>();
return body.map<User>((json) => new User.fromJson(json)).toList();
}
static List<User> getUserFromSharedPref(String jsonString){
final body = json.decode(jsonString).cast<Map<String, dynamic>>();
return body.map<User>((json) => new User.fromJson(json)).toList();
}
}
I am not getting saved data after killing the app from SharedPreferences.
I have successfully stored a value as a string in the localStorage as below:
var acceptedCompany = jsonEncode('${item.company!.name!}');
print('storedCompany: $acceptedCompany'); // succesfully prints value as 'abc'
await sharedPref.save('savedCompany', acceptedCompany);
And now I want to read the stored value from another screen and assign it to a variable which I can then bind to my Text() widget. I have successfully accessed the value within my console. However when I try to assign the stored value to a variable, I get an error:
"Instance of Future<dynamic>"
Here is how am getting back the stored value:
class _SideBarState extends State < SideBar > {
SharedPref sharedPref = SharedPref();
var savedCompany;
String key = 'storedCompany';
#override
#override
void didChangeDependencies() {
getCompany();
super.didChangeDependencies();
}
getCompany() async {
savedCompany = await sharedPref.read(key);
print('getComp: $savedCompany'); // this returns the stored value i.e 'abc' but I can't assign this to the Text widget
}
#override
Widget build(BuildContext context) {
var savedCompany2 = getCompany();
print('getComp2: $savedCompany2'.toString()); // generates an error 'Instance of Future<dynamic>'
return Text($savedCompany2);
}
}
My SharedPref Class looks like this:
read(key) async {
final prefs = await SharedPreferences.getInstance();
final value = prefs.getString(key) ? ? 0;
// print('retrievedValue: ' + '$value');
return value;
}
save(key, value) async {
final prefs = await SharedPreferences.getInstance();
// prefs.setString(key, json.encode(value));
prefs.setString(key, value);
// print('savedToken:' + '$key');
}
How can I access the sharedPreference value and assign it to the variable that I can then bind to the Text widget?
To overcome the problem, you can either set the value after the initState or using FutureBuilder.
FutureBuilder:
class SideBar extends StatefulWidget {
const SideBar({Key? key}) : super(key: key);
#override
State<SideBar> createState() => _SideBarState();
}
class _SideBarState extends State<SideBar> {
SharedPref sharedPref = SharedPref();
String key = 'storedCompany';
Future<String> getCompany() async {
return await sharedPref.read(key);
}
#override
Widget build(BuildContext context) {
return FutureBuilder<String>(
future: getCompany(),
builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
if (snapshot.hasData) {
return Text('Result: ${snapshot.data}');
} else if (snapshot.hasError) {
return Text('Error: ${snapshot.error}');
} else {
return Center(child: CircularProgressIndicator());
}
},
);
}
}
After initState():
class SideBar extends StatefulWidget {
const SideBar({Key? key}) : super(key: key);
#override
State<SideBar> createState() => _SideBarState();
}
class _SideBarState extends State<SideBar> {
SharedPref sharedPref = SharedPref();
String key = 'storedCompany';
String? _companyName;
Future<void> getCompany() async {
var name = await sharedPref.read(key);
setState(() {
_companyName = name;
});
}
#override
void initState() {
super.initState();
getCompany();
}
#override
Widget build(BuildContext context) {
if(_companyName == null) return Center(child:CircularProgressIndicator());
return Text(_companyName!);
}
}
I am working on one project with BLoC.I have made some classes to update the data.
Data will come once you pass the placeID.
But once you pass the PlaceID first time it will give the data and widgets updated.
But once I pass new placeID old data not being updated. It shows old data.
All Code Files:
RestaurantDetailBloc.dart
class RestaurantDetailBloc extends Bloc<RestaurantDetailEvent, RestaurantDetailState> {
static final RestaurantDetailBloc _restaurantDetailBlocSingleton = new RestaurantDetailBloc._internal();
factory RestaurantDetailBloc() {
return _restaurantDetailBlocSingleton;
}
RestaurantDetailBloc._internal();
RestaurantDetailState get initialState => new UnRestaurantDetailState();
#override
Stream<RestaurantDetailState> mapEventToState(
RestaurantDetailEvent event,
) async* {
try {
yield await event.applyAsync(currentState: currentState, bloc: this);
} catch (_, stackTrace) {
print('$_ $stackTrace');
yield currentState;
}
}
}
LoadRestaurantDetailEvent.dart
#immutable
abstract class RestaurantDetailEvent {
Future<RestaurantDetailState> applyAsync(
{RestaurantDetailState currentState, RestaurantDetailBloc bloc});
final RestaurantDetailProvider _provider = RestaurantDetailProvider();
}
class LoadRestaurantDetailEvent extends RestaurantDetailEvent {
#override
String toString() => 'LoadRestaurantDetailEvent';
String placeID;
LoadRestaurantDetailEvent({Key key,this.placeID});
#override
Future<RestaurantDetailState> applyAsync(
{RestaurantDetailState currentState, RestaurantDetailBloc bloc}) async {
try {
await Future.delayed(new Duration(seconds: 2));
var component = await _provider.getRestaurantReview(placeID);
print(component);
return new InRestaurantDetailState(component);
} catch (_, stackTrace) {
print('$_ $stackTrace');
return new ErrorRestaurantDetailState(_?.toString());
}
}
}
RestaurantDetailPage.dart
class RestaurantDetailPage extends StatelessWidget {
static const String routeName = "/restaurantDetail";
final String imageURL;
final String placeID;
const RestaurantDetailPage({Key key, this.imageURL,this.placeID}) : super(key: key);
#override
Widget build(BuildContext context) {
var _restaurantDetailBloc = new RestaurantDetailBloc();
return new RestaurantDetailScreen(restaurantDetailBloc: _restaurantDetailBloc,imageUrl: this.imageURL,placeId: this.placeID,);
}
}
RestaurantDetailProvider.dart
class RestaurantDetailProvider {
String getBaseUrl(String placeID){
final urlBase = "https://maps.googleapis.com/maps/api/place/details/json?placeid=$placeID&key=xxxxxxxxxxxxxGooglePlaceKey";
return urlBase;
}
Future<void> loadAsync(String token) async {
/// write from keystore/keychain
await Future.delayed(new Duration(seconds: 2));
}
Future<void> saveAsync(String token) async {
/// write from keystore/keychain
await Future.delayed(new Duration(seconds: 2));
}
Future<Map<String, dynamic>> getRestaurantReview(String placeId)async{
var response = await http.get(getBaseUrl(placeId));
RestaurantReviews reviews = RestaurantReviews();
if(response.statusCode == 200){
var decodedJson = jsonDecode(response.body);
print(decodedJson);
//reviews.result = decodedJson['result'];
return decodedJson;
}
else{
}
}
}
InRestaurantDetailState.dart
#immutable
abstract class RestaurantDetailState extends Equatable {
RestaurantDetailState([Iterable props]) : super(props);
/// Copy object for use in action
RestaurantDetailState getStateCopy();
}
/// UnInitialized
class UnRestaurantDetailState extends RestaurantDetailState {
#override
String toString() => 'UnRestaurantDetailState';
#override
RestaurantDetailState getStateCopy() {
return UnRestaurantDetailState();
}
}
class InRestaurantDetailState extends RestaurantDetailState {
final resReview;
InRestaurantDetailState(this.resReview);
#override
String toString() => 'InRestaurantDetailState';
#override
RestaurantDetailState getStateCopy() {
return InRestaurantDetailState(resReview);
}
}
class ErrorRestaurantDetailState extends RestaurantDetailState {
final String errorMessage;
ErrorRestaurantDetailState(this.errorMessage);
#override
String toString() => 'ErrorRestaurantDetailState';
#override
RestaurantDetailState getStateCopy() {
return ErrorRestaurantDetailState(this.errorMessage);
}
}
RestaurantDetailScreenState.dart
class RestaurantDetailScreen extends StatefulWidget {
const RestaurantDetailScreen({
Key key,
#required RestaurantDetailBloc restaurantDetailBloc,
this.imageUrl, this.placeId,
}) : _restaurantDetailBloc = restaurantDetailBloc,
super(key: key);
final RestaurantDetailBloc _restaurantDetailBloc;
final String imageUrl;
final String placeId;
#override
RestaurantDetailScreenState createState() {
return new RestaurantDetailScreenState(_restaurantDetailBloc, imageUrl,placeId);
}
}
class RestaurantDetailScreenState extends State<RestaurantDetailScreen> {
final RestaurantDetailBloc _restaurantDetailBloc;
final String imageUrl;
final String placeId;
RestaurantDetailScreenState(this._restaurantDetailBloc, this.imageUrl,this.placeId);
#override
void initState() {
super.initState();
this._restaurantDetailBloc.dispatch(LoadRestaurantDetailEvent(placeID:placeId));
}
#override
void dispose() {
super.dispose();
}
#override
Widget build(BuildContext context) {
SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark);
final width = MediaQuery.of(context).size.width;
final height = MediaQuery.of(context).size.height;
return BlocBuilder<RestaurantDetailBloc, RestaurantDetailState>(
bloc: widget._restaurantDetailBloc,
builder: (
BuildContext context,
var currentState,
) {
if (currentState is UnRestaurantDetailState) {
return MaterialApp(
home: new Scaffold(
body: new Container(
color: Colors.white,
child: Center(
child: CircularProgressIndicator(),
),
),
));
}
if (currentState is ErrorRestaurantDetailState) {
return new Container(
child: new Center(
child: new Text(currentState.errorMessage ?? 'Error'),
));
}
if (currentState is InRestaurantDetailState) {
var resList = currentState.resReview;
print(resList);
return MaterialApp(
home: new Scaffold(
)
);
}
Please help me guys.I have spent whole day.
Thank you in advance.
You need to pass the data to the parent class for comparison. That's why we are using equatable. Do these changes and it should work. Let me know if it doesn’t.
class InRestaurantDetailState extends RestaurantDetailState {
final resReview;
//You need to change this line to
InRestaurantDetailState(this.resReview):super([resReview]);
#override
String toString() => 'InRestaurantDetailState';
#override
RestaurantDetailState getStateCopy() {
return InRestaurantDetailState(resReview);
}
}