Flutter 登录Provider AuthService

Question

My application was working fine but after I update the whole package and flutter with the android studio it shows an error in the login section when I login/signup below is the error:

======== Exception caught by gesture ===================================================
The following ProviderNotFoundException was thrown while handling a gesture:
Error: Could not find the correct Provider<AuthService> above this SignIn Widget

This happens because you used a BuildContext that does not include the provider of your choice. There are a few common scenarios:

• You added a new provider in your main.dart and performed a hot-reload. To fix, perform a hot-restart.

• The provider you are trying to read it in a different route.

  Providers are "scoped". So if you insert of provider inside a route, then other routes will not be able to access that provider.

• You used a BuildContext that is an ancestor of the provider you are trying to read.

  Make sure that SignIn is under your MultiProvider/Provider. This usually happens when you are creating a provider and trying to read it immediately.

  For example, instead of:

   Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // Will throw a ProviderNotFoundError, because `context` is associated // to the widget that is the parent of `Provider<Example>` child: Text(context.watch<Example>()), ), }

  consider using builder like so:

   Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // we use `builder` to obtain a new `BuildContext` that has access to the provider builder: (context) { // No longer throws return Text(context.watch<Example>()), } ), }

  When the exception was thrown, this was the stack:

   #0 Provider._inheritedElementOf (package:provider/src/provider.dart:329:7) #1 Provider.of (package:provider/src/provider.dart:281:30) #2 ReadContext.read (package:provider/src/provider.dart:607:21) #3 _SignInState._toggleSignInButton (package:wallet_ui_app/pages/Login/pages/login_page.dart:391:13) #4 _SignInState.build.<anonymous closure> (package:wallet_ui_app/pages/Login/pages/login_page.dart:376:21) #5 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:989:21) #6 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:193:24) #7 TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:608:11) #8 BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:296:5) #9 BaseTapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:267:7) #10 GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:157:27) #11 GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:444:20) #12 GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:420:22) #13 RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:278:11) #14 GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:374:7) #15 GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:338:5) #16 GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:296:7) #17 GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:279:7) #21 _invoke1 (dart:ui/hooks.dart:185:10) #22 PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:293:7) #23 _dispatchPointerDataPacket (dart:ui/hooks.dart:98:31) (elided 3 frames from dart:async) Handler: "onTap" Recognizer: TapGestureRecognizer#0cb65 debugOwner: GestureDetector state: ready won arena finalPosition: Offset(216.1, 537.3) finalLocalPosition: Offset(98.3, 28.9) button: 1 sent tap down

I will post now below the code that I am getting an error from:

  void _onSignInButtonPress() {
    _pageController.animateToPage(0,
        duration: const Duration(milliseconds: 500), curve: Curves.decelerate);
  }

 void _toggleSignInButton() {
    print('_toggleSignInButton clicked');
    final String email = loginEmailController.text.trim();
    final String password = loginPasswordController.text.trim();
    context.read<AuthService>().login(
      email,
      password,
    ).whenComplete(() => IfAdminLoggedIn());
  }

Authservices.dart:

 class AuthService {
  final FirebaseAuth _auth;

  AuthService(this._auth);

  Stream<User> get authStateChanges => _auth.idTokenChanges();

  Future<String> login(String email, String password) async {

await _auth.signInWithEmailAndPassword(email: email, password: password);
}

is there any solution for this?

Answer 1

Use riverpod package its easier than provider and now with update packages provider deprecated and got too much bugs about (Provider not found)

Answer 2

The simplest solution for all providers is to include them at the root of your application, above MaterialApp.

And for the purpose of finding and debugging issues related to these providers I recommend using dart dev tools on a browser and checking out the widget hierarchy and see if the widget where you're trying to access the provider at falls under the hierarchy or not.

I had a similar issue earlier and I solved this using dart dev tools (I was easily able to spot that the provider I added was falling out of hierarchy and was not accessible, ie there was a sibling relation between widgets, which I did not expect, resulting the provider to be inaccessible).

Hope this also works for you.