Question

我做错了什么？当我尝试对_notes进行排序时，出现“构造函数的名称必须与封闭类的名称匹配”。错误。

List<Note> _notes = [
Note(id: '1', date: DateTime.utc(2020, 11, 9), title: 'One', name: 'Name1'),
Note(id: '2', date: DateTime.now(), title: 'Two', name: 'Name2'),
Note(id: '2', date: DateTime.utc(2020, 05, 15), title: 'Two', name: 'Name3')];
_notes.sort((a,b)=>a.date.difference(DateTime.now()).inDays.compareTo(b.date.difference(DateTime.now()).inDays));

Answer 1

它应该起作用：

 _notes.sort((a,b) => a.date.compareTo(b.date));

Answer 2

您确定已将代码放入例如主要？以下代码可以正常工作：

class Note {
  final String id;
  final DateTime date;
  final String title;
  final String name;

  Note({this.id, this.date, this.title, this.name});

  @override
  String toString() => 'Note(id: $id, date: $date, title: $title, name: $name)';
}

void main() {
  final _notes = [
    Note(id: '1', date: DateTime.utc(2020, 11, 9), title: 'One', name: 'Name1'),
    Note(id: '2', date: DateTime.now(), title: 'Two', name: 'Name2'),
    Note(id: '2', date: DateTime.utc(2020, 05, 15), title: 'Two', name: 'Name3')
  ];

  _notes.sort((a, b) => a.date
      .difference(DateTime.now())
      .inDays
      .compareTo(b.date.difference(DateTime.now()).inDays));

  _notes.forEach(print);
  // Note(id: 2, date: 2020-05-15 00:00:00.000Z, title: Two, name: Name3)
  // Note(id: 2, date: 2020-10-26 19:55:41.351673, title: Two, name: Name2)
  // Note(id: 1, date: 2020-11-09 00:00:00.000Z, title: One, name: Name1)
}

如何对对象列表进行排序？

2 个答案: