flutter - Provider notifyListeners() is not update Consumers - Stack Overflow

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I am using Provider in my application. I have designed a simple question-answering mechanism. My code suddenly stopped working even though I didn’t change anything. Could it be that I have reached the maximum amount of data a Provider can hold, or is it a similar issue?

...
    questionState = QuestionState.answered;
    selectedOption = option;
    notifyListeners(); // <=== THIS IS UPDATE UI
    answerResponse = await ApiService.answerQuestion(
      startResponse!.gameID,
      activeQuestionNEW!.id,
      option?.id,
      startResponse!.levelConfig.timePerQuestion - remainingTime,
    );
    await Future.delayed(const Duration(seconds: 1));
    _checkQuestionAnswer();
    answerList.add(_createAnswerObject(option: option));
    LogService.logValue(answerResponse, valueName: 'answerResponse');
    notifyListeners(); // <=== THIS IS NOT UPDATE UI
    showResultAnimation();
    _playAnswerSound();
...

I am using Provider in my application. I have designed a simple question-answering mechanism. My code suddenly stopped working even though I didn’t change anything. Could it be that I have reached the maximum amount of data a Provider can hold, or is it a similar issue?

...
    questionState = QuestionState.answered;
    selectedOption = option;
    notifyListeners(); // <=== THIS IS UPDATE UI
    answerResponse = await ApiService.answerQuestion(
      startResponse!.gameID,
      activeQuestionNEW!.id,
      option?.id,
      startResponse!.levelConfig.timePerQuestion - remainingTime,
    );
    await Future.delayed(const Duration(seconds: 1));
    _checkQuestionAnswer();
    answerList.add(_createAnswerObject(option: option));
    LogService.logValue(answerResponse, valueName: 'answerResponse');
    notifyListeners(); // <=== THIS IS NOT UPDATE UI
    showResultAnimation();
    _playAnswerSound();
...

• flutter
• user-interface
• mobile
• provider

Share Improve this question Follow asked Mar 23 at 11:39 Feyiz Oktay AydırFeyiz Oktay Aydır 9988 bronze badges 1

• 1 Could you please share where this Provider used in the UI ? because if you use more than one Consumer for different Providers on one UI component it will need to combine the Providers method together so they can work – Mahmoud Al-shehyby Commented Mar 23 at 17:32

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1 Answer 1

Sorted by: Reset to default 1

It’s possible that your second notifyListeners() is not being executed due to an error or an issue in the state management flow. To debug this, follow these steps:

• Run your app in debug mode and add breakpoints near the second notifyListeners().

• Else wrap your logic in a try-catch block to see if any error occurs before reaching notifyListeners().

try {
  answerResponse = await ApiService.answerQuestion(
    startResponse!.gameID,
    activeQuestionNEW!.id,
    option?.id,
    startResponse!.levelConfig.timePerQuestion - remainingTime,
  );
  await Future.delayed(const Duration(seconds: 1));
  _checkQuestionAnswer();
  answerList.add(_createAnswerObject(option: option));
  LogService.logValue(answerResponse, valueName: 'answerResponse');

  notifyListeners(); // <=== Check if this executes
} catch (e, stackTrace) {
  debugPrint("Error before notifyListeners: $e");
  debugPrint(stackTrace.toString());
}

• Calling notifyListeners() updates only the widgets that are actively listening to the provider at that moment. Check if your Consumer or Selector widget is properly wrapped around the widget that should rebuild.

Consumer<MyProvider>(
  builder: (context, provider, child) {
    return Text(provider.someValue);
  },
);

If still not updating? Share more code which can help to reproduce the issue and understanding the problem ✌️

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