I have 4 pages. I called getRide() method in every 4 pages. it's means 4 times database call. Am I right? Is it possible to create a singleton for this scenario?
Firebase Service:
class FirebaseService {
final Firestore _db = Firestore.instance;
Stream<List<RideModel>> getRide() {
return _db.collection('ride')
.snapshots()
.map((list) => list.documents.map((doc) => RideModel.fromFirestore(doc))
.toList());
}
}
Calling Method:
#override
void initState() {
super.initState();
db.getRide().listen(getRide);
}
void getRide(List<RideModel> model) {
if (!mounted) return;
setState(() {
rideModel = model;
});
}
I can't pass rideModel through Navigator. because when change data in ride collection need to change 4 pages UI.
Someone tells me this answer is correct for the above problem.
I found this way to solve this problem.
I used get_it package and create service locator,
GetIt locator = GetIt.instance;
void setupSingletons() async {
locator.registerLazySingleton<FirebaseService>(() => FirebaseService());
}
And then added to the main class
void main() {
setupSingletons();
runApp(MultiProvider(
providers: globalProviders,
child: MyApp(),
));
}
And every screen I added,
class _Screen1 extends State<Screen1> {
// final db = FirebaseService();
FirebaseService db = GetIt.I.get<FirebaseService>();
Related
I've developed a Unity App that uses Firebase as a BaaS and Firestore as a Database.
Firebase has a Client SDK to make calls that are usually called from client to server by an URL endpoint.
My concern is how my methods should be implemented to correctly work on client without blocking the user experience, cause if I made a heavy request, my Unity App is blocked, and no interaction is allowed to the user.
This is the code of my client DatabaseManager with the methods to retrieve a User from Firestore:
public class DatabaseManager
{
public DatabaseManager(FirebaseFirestore db)
{
this.db = db;
}
public async Task<User> GetUserByUIDAsync(string uid)
{
string documentID = uid;
return await AsyncGetDocumentFromCollection<User, User_FirestoreData>(COL_ID_USERS, documentID);
}
public async Task<PlainData> AsyncGetDocumentFromCollection<PlainData, FirestoreData>(string collectionID, string documentID) where PlainData : IConvertToFirestore<FirestoreData> where FirestoreData : IConvertToPlainData<PlainData>
{
try
{
DocumentReference docRef = db.Collection(collectionID).Document(documentID);
DocumentSnapshot documentSnapshot = await docRef.GetSnapshotAsync();
if (documentSnapshot.Exists)
{
Debug.Log("Get Document data for document:" + documentSnapshot.Id);
FirestoreData firestoreData = documentSnapshot.ConvertTo<FirestoreData>();
return firestoreData.ToPlainData();
}
else
{
Debug.Log($"Document {documentSnapshot.Id} does not exist!");
}
}
catch (Exception e)
{
Debug.Log(e);
}
return default(PlainData);
}
}
This is a simple call and when it's called from any MonoBehaviouryou couldn't notice the load difference when you call it like:
using UnityEngine.UI;
public class MyMono : MonoBehaviour
{
private void DatabaseManager db;
[SerializedField] private Button button = null;
private void Awake()
{
button.onClick.AddListener(async ()=> await CustomAwakeAsync(db));
}
private async Task CustomAwakeAsync(DatabaseManager db)
{
//if this Async method is heavier, this will block the main UI thread when the button is pressed
await db.GetUserByUIDAsync("xdfipñfajrfiñar");
}
}
But if instead of GetUserByUIDAsync I make a heavy call, or multiple recursive calls my application UI will freeze until it's finished...which is bad.
How should I build my code to avoid these case?
Note:
My easy way to test if it's blocking UI thread is having this class attached to a GameObject with Image component:
using UnityEngine;
public class InfiniteRotate : MonoBehaviour
{
public float speed = 1;
// Update is called once per frame
private void Update()
{
this.gameObject.transform.Rotate(0, 0, 1 * Time.deltaTime * speed);
}
}
If the image stop spinning, means that async/await is blocking the UI thread.
Your code as shown:
private void CustomAwake(DatabaseManager db)
{
await db.GetUserByUIDAsync("xdfipñfajrfiñar");
}
...should be producing the following error:
error CS4033: The 'await' operator can only be used within an async method. Consider marking this method with the 'async' modifier and changing its return type to 'Task'.
Even if somehow you managed to silence this error the method signature private void CustomAwake(DatabaseManager db) clearly indicates that this method is synchronous to the caller.
OP:
But if instead of GetUserByUIDAsync I make a heavy call, my application UI will freeze until it's finished...which is bad.
So if you are calling this from the same thread as Update, FixedUpdate etc (which by the looks of it you are) then you are going to block Unity and thus slow down your game.
If you are going to use async/await then you need to do so all the way back to the original caller.
Make it asynchronous
Change the method to:
private async Task<User> CustomAwake(DatabaseManager db) // Note the async Task
{
return await db.GetUserByUIDAsync("xdfipñfajrfiñar");
}
...and ensure that whatever calls it uses await in order to get the User.
A custom object that takes a parameter of (DocumentSnapShot documentsnapShot). also is an inner object from Firebase that retrieves a snapshot and set the values to my custom model also have its argument (DocumentSnapShot documentsnapShot). However, I wish to get the data from Firebase and pass it to my custom argument because mine takes multiple data not only Firebase. And it's not possible to iterate Firestore without an override.
Here's the code:
public UserSettings getUserSettings(DocumentSnapshot documentSnapshot){
Log.d(TAG, "getUserSettings: retrieving user account settings from firestore");
DocumentReference mSettings = mFirebaseFirestore.collection("user_account_settings").document(userID);
mSettings.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
#Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
UserAccountSettings settings = documentSnapshot.toObject(UserAccountSettings.class);
settings.setDisplay_name(documentSnapshot.getString("display_name"));
settings.setUsername(documentSnapshot.getString("username"));
settings.setWebsite(documentSnapshot.getString("website"));
settings.setProfile_photo(documentSnapshot.getString("profile_photo"));
settings.setPosts(documentSnapshot.getLong("posts"));
settings.setFollowers(documentSnapshot.getLong("followers"));
settings.setFollowing(documentSnapshot.getLong("following"));
}
});
}
You cannot return something now that hasn't been loaded yet. Firestore loads data asynchronously, since it may take some time for this. Depending on your connection speed and the state, it may take from a few hundred milliseconds to a few seconds before that data is available. If you want to pass settings object to another method, just call that method inside onSuccess() method and pass that object as an argument. So a quick fix would be this:
#Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
UserAccountSettings settings = documentSnapshot.toObject(UserAccountSettings.class);
yourMethod(settings);
}
One more thing to mention is that you don't need to set the those values to object that already have them. You are already getting the data from the database as an object.
So remember, onSuccess() method has an asynchronous behaviour, which means that is called even before you are getting the data from your database. If you want to use the settings object outside that method, you need to create your own callback. To achieve this, first you need to create an interface like this:
public interface MyCallback {
void onCallback(UserAccountSettings settings);
}
Then you need to create a method that is actually getting the data from the database. This method should look like this:
public void readData(MyCallback myCallback) {
DocumentReference mSettings = mFirebaseFirestore.collection("user_account_settings").document(userID);
mSettings.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
#Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
UserAccountSettings settings = documentSnapshot.toObject(UserAccountSettings.class);
myCallback.onCallback(settings);
}
});
}
In the end just simply call readData() method and pass an instance of the MyCallback interface as an argument wherever you need it like this:
readData(new MyCallback() {
#Override
public void onCallback(UserAccountSettings settings) {
Log.d("TAG", settings.getDisplay_name());
}
});
This is the only way in which you can use that object of UserAccountSettings class outside onSuccess() method. For more informations, you can take also a look at this video.
Use LiveData as return type and observe the changes of it's value to execute desired operation.
private MutableLiveData<UserAccountSettings> userSettingsMutableLiveData = new MutableLiveData<>();
public MutableLiveData<UserAccountSettings> getUserSettings(DocumentSnapshot documentSnapshot){
DocumentReference mSettings = mFirebaseFirestore.collection("user_account_settings").document(userID);
mSettings.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
#Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
UserAccountSettings settings = documentSnapshot.toObject(UserAccountSettings.class);
settings.setDisplay_name(documentSnapshot.getString("display_name"));
settings.setUsername(documentSnapshot.getString("username"));
settings.setWebsite(documentSnapshot.getString("website"));
settings.setProfile_photo(documentSnapshot.getString("profile_photo"));
settings.setPosts(documentSnapshot.getLong("posts"));
settings.setFollowers(documentSnapshot.getLong("followers"));
settings.setFollowing(documentSnapshot.getLong("following"));
userSettingsMutableLiveData.setValue(settings);
}
});
return userSettingsMutableLiveData;
}
Then from your Activity/Fragment observe the LiveData and inside onChanged do your desired operation.
getUserSettings().observe(this, new Observer<UserAccountSettings>() {
#Override
public void onChanged(UserAccountSettings userAccountSettings) {
//here, do whatever you want on `userAccountSettings`
}
});
I am trying to add Firebase Analytics to my flutter app to display different screen names on the dashboard. I used a method that I found here on stackoverflow in this link:
How do I track Flutter screens in Firebase analytics?
I added this code in a separate file:
import 'package:firebase_analytics/firebase_analytics.dart';
import 'package:flutter/widgets.dart';
// A Navigator observer that notifies RouteAwares of changes to state of their Route
final routeObserver = RouteObserver<PageRoute>();
mixin RouteAwareAnalytics<T extends StatefulWidget> on State<T>
implements RouteAware {
AnalyticsRoute get route;
#override
void didChangeDependencies() {
routeObserver.subscribe(this, ModalRoute.of(context) as PageRoute<dynamic>);
super.didChangeDependencies();
}
#override
void dispose() {
routeObserver.unsubscribe(this);
super.dispose();
}
#override
void didPop() {}
#override
void didPopNext() {
// Called when the top route has been popped off,
// and the current route shows up.
_setCurrentScreen(route);
}
#override
void didPush() {
// Called when the current route has been pushed.
_setCurrentScreen(route);
}
#override
void didPushNext() {}
Future<void> _setCurrentScreen(AnalyticsRoute analyticsRoute) {
print('Setting current screen to $analyticsRoute');
return FirebaseAnalytics.**setCurrentScreen**(
screenName: screenName(analyticsRoute),
screenClassOverride: screenClass(analyticsRoute),
);
}
}
enum AnalyticsRoute { screenName }
String screenClass(AnalyticsRoute route) {
switch (route) {
case AnalyticsRoute.screenName:
return 'screenName';
}
throw ArgumentError.notNull('route');
}
String screenName(AnalyticsRoute route) {
switch (route) {
case AnalyticsRoute.screenName:
return '/screenName';
}
throw ArgumentError.notNull('route');
}
I then added the route observer in the screen that I want to track.
The setCurrentScreen method is not working well and the app is not building. Any suggestions on what I could do to build it.
From the FlutterFire documentation on screen tracking:
await FirebaseAnalytics.instance
.setCurrentScreen(
screenName: 'Products'
);
I'm currently working on a simple project crypto_wallet. State management (BLoC) and Value Equality (freezed) creating CRUD operation of DB (Firebase) and in the watch method, I use StreamSubcription code is :
#injectable
class CoinWatcherBloc extends Bloc<CoinWatcherEvent, CoinWatcherState> {
final ICoinRepository _repository;
CoinWatcherBloc(this._repository, this._coinStreamSubscription) :
super(CoinWatcherState.initial());
StreamSubscription<Either<CoinFailure, KtList<CoinEntity>>>? _coinStreamSubscription;
#override
Stream<CoinWatcherState> mapEventToState(CoinWatcherEvent event) async* {
yield* event.map(
watchCoin: (e) async* {
yield CoinWatcherState.loadInProgress();
await _coinStreamSubscription?.cancel();
_coinStreamSubscription = _repository.watchCoin().listen(
(failureOrSuccess) => add(
CoinWatcherEvent.coinsReceived(failureOrSuccess),
),
);
},
coinsReceived: (e) async* {
yield e.failureOrCoin.fold(
(f) => CoinWatcherState.loadFailure(f),
(coin) => CoinWatcherState.loadSuccess(coin),
);
},
);
}
#override
Future<void> close() async {
await _coinStreamSubscription?.cancel();
return super.close();
}
}
And at last I closed the stream. I inject all third party modules on #lazySingleton :
#module
abstract class FirebaseInjectableModule {
#lazySingleton
FirebaseAuth get firebaseAuth => FirebaseAuth.instance;
#lazySingleton
FirebaseFirestore get firebaseFirestore => FirebaseFirestore.instance;
#lazySingleton
GoogleSignIn get googleSignIn => GoogleSignIn();
}
Then It says :
Object/factory with type StreamSubscription<Either<CoinFailure, KtList<CoinEntity>>> is not
registered inside GetIt.
(Did you accidentally do GetIt sl=GetIt.instance(); instead of GetIt sl=GetIt.instance;
Did you forget to register it?)
If I also register this class like this.
#lazySingleton
StreamSubcription get streamSubcription => StreamSubcription();
Then it throws compile time error that abstract classes can't be instantiated like the all Third Party Classes I've registered. How to inject abstract classes? Is there any other way to do this? or I shouldn't use StreamSubcription something else? I'd be thankful <3 :)
You should not add this._coinStreamSubscription to your bloc's constructor. Remove it from the constructor, and declare it as a late final instance.
class CoinWatcherBloc extends Bloc<CoinWatcherEvent, CoinWatcherState> {
final ICoinRepository _repository;
CoinWatcherBloc(this._repository) :
super(CoinWatcherState.initial());
late final StreamSubscription<Either<CoinFailure, KtList<CoinEntity>>>? _coinStreamSubscription;
get_it was trying to inject the abstract streamSubscription since it is in your constructor. And you do not need this. Also, if you look at it from a testing perspective, there is no need to mock the streamSubscription, you can instead mock the class that supplies data to it - which is the repository in this case
I generally just inject the implementation of the abstract class like
#LazySingleton(as:AbstractClass).
I have a flutter app talking to the Firebase Realtime Database. I get the data asynchronously, obviously, but my UI allows the user to move to a different part of the app, which means by the time the request completes, the Widget may be unmounted. Best practices say to cancel the async work instead of checking the mounted property but I cannot seem to figure out how to do this for some reason.
#override void initState() {
super.initState();
firebaseRealtimeReference.child('myData').once().then((results) {
if (mounted) {
setState(() {
_myLocalData = results;
}
}
}
/* Alternately with async/await: */
_myLocalData = firebaseRealtimeDatabaseReference.child('myData').once();
}
#override Widget build(BuildContext context) {
return new MyWidget(_myLocalData);
}
#override dispose() {
// Instead of checking mounted in the future, I should instead
// cancel the work in progress here.
super.dispose();
}