flutter - Dart : ambiguous_set_or_map_literal_both

Question

您好，我是 Flutter 移动应用程序开发新手，正在学习 udemy 类(class)。 我陷入了一个困境，即讲师可以使用 map 和文字变量创建变量，而在我的编辑器中我收到此错误，上面写着

This literal contains both 'Map' and 'Iterable' spreads, which makes it impossible to determine whether the literal is a map or a set. Try removing or changing some of the elements so that all of the elements are consistent

我和导师一起检查了代码很多次，也检查了 Dart 官方文档，但无法解决它。如果有人可以帮助我，请。 谢谢。

final _questions = const [
    {
      'questionText':
          'Who is the current president of The United Stated of America?',
      'answers': [
        {'text': 'Donald Trump', 'score': 10},
        {'text': 'Ram Nath Kovind', 'score': -10},
        {'text': 'Pedro Sánchez', 'score': -10},
      ],
    },
    {
      'questionText': 'Which of these is the currency used in Japan?',
      'answers': {'text': 'Ringgit', 'score': -10},
      {'text': 'Yuan', 'score': -10},
      {'text': 'Yen', 'score': 10},
    },
    {
      'questionText': 'Which of these is the capital of Spain?',
      'answers': {'text': 'Madrid', 'score': 10},
      {'text': 'Washington DC', 'score': -10},
      {'text': 'Moscow', 'score': -10},
    },
    {
      'questionText': 'Which one is the language of Israel?',
      'answers': {'text': 'Persian', 'score': -10},
      {'text': 'Hebrew', 'score': 10},
      {'text': 'Turkish', 'score': -10},
    },
    {
      'questionText': 'Who among these was the Missile Man of India?',
      'answers': {'text': 'Pranab Mukherjee', 'score': -10},
      {'text': 'Sir APJ Abdul Kalam', 'score': 10},
      {'text': 'Bhagat Singh', 'score': -10}, 
    },
  ];

这是包含一些问题集的变量。 Screenshot of code

检查屏幕截图以获取更多错误信息。

Answer 1

answers 第一个元素是数组，接下来的元素语法错误

这应该有效

final _questions = const [
    {
      'questionText':
          'Who is the current president of The United Stated of America?',
      'answers': [
        {'text': 'Donald Trump', 'score': 10},
        {'text': 'Ram Nath Kovind', 'score': -10},
        {'text': 'Pedro Sánchez', 'score': -10},
      ],
    },
    {
      'questionText': 'Which of these is the currency used in Japan?',
      'answers': [
        {'text': 'Ringgit', 'score': -10},
        {'text': 'Yuan', 'score': -10},
        {'text': 'Yen', 'score': 10}
      ]
    },
    {
      'questionText': 'Which of these is the capital of Spain?',
      'answers': [
        {'text': 'Madrid', 'score': 10},
        {'text': 'Washington DC', 'score': -10},
        {'text': 'Moscow', 'score': -10}
      ]
    },
    {
      'questionText': 'Which one is the language of Israel?',
      'answers': [
        {'text': 'Persian', 'score': -10},
        {'text': 'Hebrew', 'score': 10},
        {'text': 'Turkish', 'score': -10}
      ]
    },
    {
      'questionText': 'Who among these was the Missile Man of India?',
      'answers': [
        {'text': 'Pranab Mukherjee', 'score': -10},
        {'text': 'Sir APJ Abdul Kalam', 'score': 10},
        {'text': 'Bhagat Singh', 'score': -10}
      ]
    },
  ];