Parse nested XML in Dart / Flutter

Question

I need help parsing a nested XML file in Dart/Flutter.

I have a Dart class

class Genre {
String id;
String title;
String token;
String type;
// For children objets I want to get list of IDs
// as String
List subGenres;
}

The XML file looks as follow:

So I have maybe unlimited levels of sub-genres. If a type of object is 'root' or 'container' it contains sub-genres, type 'genre' is a single record (like folders and files).

How can I get the list of all of my objects and parse it to class objects ?

Richard Heap · Accepted Answer

Use the xml package. I like to use a factory constructor that takes an XmlElement. There's no reason to limit yourself to a List for the children; you could have a List to build a tree that mirrors your XML. (You could, of course, do that instead if you prefer.)

Notice how the factory constructor iterates through any child XML elements, recursively calling itself. The normal constructor is private, so that only the factory constructor uses it. If a genre has no sub-genres, the subGenres list isEmpty.

import 'package:xml/xml.dart';

var sample = '''

  
    
    
      
      
      
    
  
  
    
    
  

''';

class Genre {
  Genre._(this.id, this.title, this.token, this.type, this.subGenres);

  factory Genre.fromElement(XmlElement genreElement) {
    return Genre._(
      genreElement.getAttribute('id'),
      genreElement.getAttribute('title'),
      genreElement.getAttribute('token'),
      genreElement.getAttribute('type'),
      genreElement
          .findElements('genre')
          .map((e) => Genre.fromElement(e))
          .toList(),
    );
  }

  String id;
  String title;
  String token;
  String type;
  List subGenres;
}

void main() {
  var root = XmlDocument.parse(sample).getElement('genres');
  var rootGenres = root
      .findElements('genre')
      .map((e) => Genre.fromElement(e))
      .toList();

  print(rootGenres);
}

Parse nested XML in Dart / Flutter

Answers (1)

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