How to convert a grouped map to list in Flutter-CodePudding

I have this grouped map. I need to convert this map to a list for using this inside a listview builder.

        Plants Around Us: [
    {sequenceno: 193, 
    _id: 5f041, 
    chapter: Plants Around Us, 
    title: Plants Around Us, 
    package_description: In this module, let us discuss about different types of plants and about different places they live.,
     age_level: [99, 6], 
    pkg_sequence: 100, 
    packagescors: []},
         {sequenceno: 193,
     _id: 5ec50, 
    chapter: Plants Around Us,
     title: Activity: Types of Plants,
     package_description: Let us go through some activities based on the lesson ‘Types of Plants’., 
    age_level: [99, 6], 
    pkg_sequence: 101, 
    packagescors: []}
],
Leaves and Flowers: [
{sequenceno: 193,
 _id: 5c48, 
chapter: Leaves and Flowers, 
title: Leaves and Flowers,
 package_description: In this article,
 age_level: [99, 6], 
pkg_sequence: 100,
 packagescors: []},

How can I convert this grouped map to a List?

Model for the grouped data

class Chapter {
  String? chapter;
  List<Title>?title;

  Chapter({this.chapter,this.title});
  factory Chapter.fromMap(Map<String, dynamic> map) {
    return Chapter(
      chapter: map['chapter'],
      title: map["title"] != null
          ? List<Title>.from(
              map["title"].map((x) => Title.fromMap(x)))
          : [],
    );
  }
  Map<String, dynamic> toMap(){
      var map = <String,dynamic>{
      };
       return map;
      }
}

Title Model

class Title{
  String? sequenceno;
  String? id;
  String? chapter;
   String? title;
  String? packageDescription;
  String? ageLevel;
  String? pkgSequence;
  String? packagescors;
  Title({
    this.sequenceno,
    this.id,
    this.chapter,
    this.title,
    this.packageDescription,
    this.ageLevel,
    this.pkgSequence,
    this.packagescors,
  });
  factory Title.fromMap(Map<String, dynamic> map) {
    return Title(
      sequenceno: map['sequenceno'],
      id: map["_id"],
      chapter: map['chapter'],
      title: map['title'],
      packageDescription: map['package_description'],
      ageLevel: map['age_level'],
      pkgSequence: map['pkg_sequence'],
      // packagescors: map['packagescors'],
    );
}
Map<String, dynamic> toMap(){
      var map = <String,dynamic>{
        "sequenceno": sequenceno,
        "_id": id,
        "chapter": chapter,
        "title": title,
        "package_description": packageDescription,
        "age_level": ageLevel,
        "pkg_sequence": pkgSequence,
        // "packagescors": packagescors,
      };
       return map;
      }}

I created this model, because of the 'Chapter' is how its grouped and 'Title' Contains Multiple values all the related data of including id, and all other values

CodePudding user response：

You could simply do this

void main() {
  List<Map<String, List>> theList = [];
  theList.add({"Leaves and Flowers" : [{" _id": "5c48", "chapter": "Leaves and Flowers", "age_level": [99, 6]}]});
  print(theList);

  // output would be
  // [{Leaves and Flowers: [{ _id: 5c48, chapter: Leaves and Flowers, age_level: [99, 6]}]}]
}

But it can tend to get real messy, I suggest you take a look at classes & objects.

class LeafModel {
  String _id = "";
  String chapter = "";
  List<int> ageLevel = [];

  LeafModel(String _id, String chapter, List<int> ageLevel);
}

void main() {
  List<LeafModel> theList = [];
  theList.add(LeafModel("ID", "CHAPTER", [15, 16]));
}

Here's an example of how it'd look.

CodePudding user response：

First create a model where you will hide all your data (be careful with data variables) and then create a list based on your model, then import all your data into your model like this;

List<YourModel> yourModel = mapData.map((doc) => YourModel.fromMap(doc.data())).toList();