Dart 如何转换列表<；列表<；地图<；字符串，字符串>&燃气轮机&燃气轮机；进入列表<；列表<；CustomObject>&燃气轮机；飞镖

我想把一个列表转换成一个自定义类，如何在dart中实现这一点

如何转换这个

List<List<Map<String, String>>> = [
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "IDP - Industrial Design Project phase II",
        "credit": "4",
        "hours": "40",
      }
    ],
    [
      {
        "course_name": "Data Base Management System",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
    ],
  ];

---

像这样的东西可以达到目的：

class StudentTimeTable {
  final String courseName;
  final String credit;
  final String hours;

  StudentTimeTable.fromMap(Map<String, String> map)
      : courseName = map['course_name'],
        credit = map['credit'],
        hours = map['hours'];

  @override
  String toString() =>
      'StudentTimeTable(courseName = $courseName, credit = $credit, hours = $hours)';
}

void main() {
  List<List<Map<String, String>>> input = [
    [
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "IDP - Industrial Design Project phase II",
        "credit": "4",
        "hours": "40",
      }
    ],
    [
      {
        "course_name": "Data Base Management System",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
    ],
  ];

  List<List<StudentTimeTable>> output = [
    ...input.map(
        (subList) => [...subList.map((map) => StudentTimeTable.fromMap(map))])
  ];

  output.forEach(print);
  // [StudentTimeTable(courseName = Estimation & Quantity Surveying, credit = 4, hours = 40), StudentTimeTable(courseName = IDP - Industrial Design Project phase II, credit = 4, hours = 40)]
  // [StudentTimeTable(courseName = Data Base Management System, credit = 4, hours = 40), StudentTimeTable(courseName = Estimation & Quantity Surveying, credit = 4, hours = 40)]
}

它返回一个列表，其中包含从

subList.map

返回的迭代器中的元素。此

map

的目的是将

map

转换为

studentchedule

这是通过调用我们的新构造函数来完成的，该构造函数采用

映射

：

---

像这样的东西可以达到目的：

class StudentTimeTable {
  final String courseName;
  final String credit;
  final String hours;

  StudentTimeTable.fromMap(Map<String, String> map)
      : courseName = map['course_name'],
        credit = map['credit'],
        hours = map['hours'];

  @override
  String toString() =>
      'StudentTimeTable(courseName = $courseName, credit = $credit, hours = $hours)';
}

void main() {
  List<List<Map<String, String>>> input = [
    [
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "IDP - Industrial Design Project phase II",
        "credit": "4",
        "hours": "40",
      }
    ],
    [
      {
        "course_name": "Data Base Management System",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
    ],
  ];

  List<List<StudentTimeTable>> output = [
    ...input.map(
        (subList) => [...subList.map((map) => StudentTimeTable.fromMap(map))])
  ];

  output.forEach(print);
  // [StudentTimeTable(courseName = Estimation & Quantity Surveying, credit = 4, hours = 40), StudentTimeTable(courseName = IDP - Industrial Design Project phase II, credit = 4, hours = 40)]
  // [StudentTimeTable(courseName = Data Base Management System, credit = 4, hours = 40), StudentTimeTable(courseName = Estimation & Quantity Surveying, credit = 4, hours = 40)]
}

它返回一个列表，其中包含从

subList.map

返回的迭代器中的元素。此

map

的目的是将

map

转换为

studentchedule

这是通过调用我们的新构造函数来完成的，该构造函数采用

映射

：

---

我只需要列表中的输出，这将帮助我实现这一点。输出已经是那种类型。我只是用foreach更容易打印。谢谢你，我的朋友，这真是一个魔术，效果很好。你能解释一下这是如何工作的吗？添加了一些解释。现在如何使用共享首选项保存和获取此列表？我只需要列表中的输出，这将帮助我实现这一点。输出已经是那种类型了。我只是用foreach更容易打印。谢谢你，我的朋友，这真是一个魔术，效果很好。你能解释一下这是如何工作的吗？添加了一些解释。现在如何使用共享首选项保存和获取此列表？

class StudentTimeTable {
  final String courseName;
  final String credit;
  final String hours;

  StudentTimeTable.fromMap(Map<String, String> map)
      : courseName = map['course_name'],
        credit = map['credit'],
        hours = map['hours'];

  @override
  String toString() =>
      'StudentTimeTable(courseName = $courseName, credit = $credit, hours = $hours)';
}

void main() {
  List<List<Map<String, String>>> input = [
    [
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "IDP - Industrial Design Project phase II",
        "credit": "4",
        "hours": "40",
      }
    ],
    [
      {
        "course_name": "Data Base Management System",
        "credit": "4",
        "hours": "40",
      },
      {
        "course_name": "Estimation & Quantity Surveying",
        "credit": "4",
        "hours": "40",
      },
    ],
  ];

  List<List<StudentTimeTable>> output = [
    ...input.map(
        (subList) => [...subList.map((map) => StudentTimeTable.fromMap(map))])
  ];

  output.forEach(print);
  // [StudentTimeTable(courseName = Estimation & Quantity Surveying, credit = 4, hours = 40), StudentTimeTable(courseName = IDP - Industrial Design Project phase II, credit = 4, hours = 40)]
  // [StudentTimeTable(courseName = Data Base Management System, credit = 4, hours = 40), StudentTimeTable(courseName = Estimation & Quantity Surveying, credit = 4, hours = 40)]
}

List<List<StudentTimeTable>> output = [...input.map((subList) => ...)]

[...subList.map((map) => StudentTimeTable.fromMap(map))]

  StudentTimeTable.fromMap(Map<String, String> map)
      : courseName = map['course_name'],
        credit = map['credit'],
        hours = map['hours'];

  final output = <List<StudentTimeTable>>[];

  for (final sublist in input) {
    final studentTimeTableSubList = <StudentTimeTable>[];

    for (final map in sublist) {
      studentTimeTableSubList.add(StudentTimeTable.fromMap(map));
    }

    output.add(studentTimeTableSubList);
  }

  final output = [
    for (final sublist in input)
      [for (final map in sublist) StudentTimeTable.fromMap(map)]
  ];