如何在Flutter/Dart中随机排列元素？

dgiusagp 于 2022-11-30 发布在 Flutter

关注(0)|答案(2)|浏览(218)

我正在尝试随机排序将出现在列中的小部件。

Widget build(BuildContext context){    return Column(
  children: [
    Question(
      questions[questionIndex]['singular'],
    ),
    ...(questions[questionIndex]['answers'] as List<Map<String, Object>>).map((answer) {
      return Answer(() => answerQuestion(answer['score']), answer['text']);
    }).toList()
  ],
);
}

我想打乱小部件中启动...(questions[questionIndex]...的部分，但当我这样做时，将.shuffle()添加到列表中，会出现Spread elements in list or set literals must implement 'Iterable'.错误。我也尝试过将打乱操作移到initState方法中，但随后应用程序会构建，但当我运行应用程序时，我在屏幕上看到错误。（NoSuchMethodError: 'shuffle'）。有人知道如何随机排列小部件列表吗？

flutter

来源：https://stackoverflow.com/questions/74588381/how-can-i-randomly-order-my-elements-in-flutter-dart

2条答案

按热度按时间

tjrkku2a1#

试试这个：

Widget build(BuildContext context) {
    var answers = (questions[questionIndex]['answers'] as List<Map<String, Object>>);
    answers.shuffle();
    return Column(
      children: [
        Question(
          questions[questionIndex]['singular'],
        ),
        ...answers
            .map((answer) {
          return Answer(() => answerQuestion(answer['score']), answer['text']);
        }).toList()
      ],
    );
  }

赞(0）回复(0）举报 2022-11-30

plicqrtu2#

使用shuffle方法对列表进行随机化/随机化：

...((questions[questionIndex]['answers'] as List<Map<String, Object>>)..shuffle())

- 完整代码：**

Column(
  children: [
    Question(
      questions[questionIndex]['singular'],
    ),
    ...((questions[questionIndex]['answers'] as List<Map<String, Object>>)
          ..shuffle())
        .map((answer) {
      return Answer(() => answerQuestion(answer['score']), answer['text']);
    }).toList()
  ],
)

赞(0）回复(0）举报 2022-11-30

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如何在Flutter/Dart中随机排列元素？

2条答案

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