在 Flutter 中出现“未引用声明”错误，即使它在 main.dart 中被引用

Question

I am completing the Angela Yu Flutter course, am working on the "Quizzler" project, and continue to get an error stating that the declaration in a dart file isn't referenced, however it appears (to me) to be. Both getQuestionText and getQuestionAnswer are resulting in the same error. I have made sure to import quiz_brain.dart into main.dart. Any help would be very much appreciated.

excerpt from quiz_brain.dart:

  void nextQuestion (){
    if (_questionNumber < _questionBank.length){_questionNumber++;
  }

  String get() {
    return _questionBank[_questionNumber].questionText;
  }

    String getQuestionText (){
      return _questionBank[_questionNumber].questionText;
  }
  bool getQuestionAnswer () {
    return _questionBank[_questionNumber].questionAnswer;
  }
}

excerpt from main.dart:

Expanded(
          flex: 5,
          child: Padding(
            padding: EdgeInsets.all(10.0),
            child: Center(
              child: Text(
                quizBrain.getQuestionText(),
                textAlign: TextAlign.center,
                style: TextStyle(
                  fontSize: 25.0,
                  color: Colors.white,
                ),
              ),
            ),
          ),
        ),

Answer 1

Have you checked if quizBrain has been initialized in main.dart? Make sure that quizBrain also has access to List _questionBank

Answer 2

With the quiz_brain.dart excerpt that you provided, please make sure you have your curly braces correct. You missed the curly closing braces for your nextQuestion() function. Because of that misplacement of that curly closing braces from the nextQuestion() function, you had an extra curly closing brace at the bottom of your excerpt.

Corrected quiz_brain.dart

void nextQuestion (){
  if (_questionNumber < _questionBank.length){
    _questionNumber++;
  }
}

String get() {
  return _questionBank[_questionNumber].questionText;
}

String getQuestionText () {
    return _questionBank[_questionNumber].questionText;
}

bool getQuestionAnswer () {
  return _questionBank[_questionNumber].questionAnswer;
}

Secondly, your get() function and getQuestionText() function does exactly the same thing, you may want to removing one of it.