Map of object containing a List<Object> for sqlite

Question

I am setting up my model classes to confirm to the docs for sqflite which suggest including a named constructor to convert to/from Maps to better handling of data between th

Answer 1

Here I am explaining the following

1. How to convert a model object into Map to use with sqlite
2. How to convert a Map object from sqlite into a model class.
3. How to parse JSON reponse properly in flutter
4. How to convert a model object into JSON

All of the above questions has same answer. Dart has great support for these operations. Here I am going to illustrate it with a detailed example.

class DoctorList{
  final List<Doctor> doctorList;

  DoctorList({this.doctorList});

  factory DoctorList.fromMap(Map<String, dynamic> json) {
    return DoctorList(
      doctorList: json['doctorList'] != null
          ? (json['doctorList'] as List).map((i) => Doctor.fromJson(i)).toList()
          : null,
    );
  }

  Map<String, dynamic> toMap() {
    final Map<String, dynamic> data = Map<String, dynamic>();
    if (this.doctorList != null) {
      data['doctorList'] = this.doctorList.map((v) => v.toMap()).toList();
    }
    return data;
  }
}

The above DoctorList class has a member which holds a list of 'Doctor' objects..

And see how I parsed the doctorList.

 doctorList: json['doctorList'] != null
      ? (json['doctorList'] as List).map((i) => Doctor.fromMap(i)).toList()
      : null,

You may wonder, how the Doctor class may look like. Here you go

class Doctor {
  final String doCode;
  final String doctorName;

  Doctor({this.doCode, this.doctorName});

  factory Doctor.fromMap(Map<String, dynamic> json) {
    return Doctor(
      doCode: json['doCode'],
      doctorName: json['doctorName'],
    );
  }

  Map<String, dynamic> toMap() {
    final Map<String, dynamic> data = Map<String, dynamic>();
    data['doCode'] = this.doCode;
    data['doctorName'] = this.doctorName;
    return data;
  }

}

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That's all. Hope you got the idea. Cheers!