title: How to parse JSON without key in flutter
body: <p>I want parse a JSON. But this JSON not have key-value. Is only value.</p>
  
  <p>I tried creating the class but dont work. The error is type 'List' is not a subtype of type 'Map'.</p>
  
  <p>I tried to parse in the positions they occupy in the json (eg.: json [0] ....) But I'm not sure about this.</p>
  
  <p>Thanks in advance</p>
  
  <p>Json: </p>
  
  <pre><code>[["P170","P171","L-18"],["P171","L806","L-18"],["L806","L807","L-18"],["L807","L120","L-18"],["L120","L121","L-18"],["L121","L122","L-18"]]
  </code></pre>
  
  <p>Class list:</p>
  
  <pre><code>import 'NodoPOJO.dart';
  class NodoCollection{
    final List&lt;NodoPOJO&gt; list;
  
    NodoCollection(this.list);
  
    factory NodoCollection.fromJson(Map&lt;String, dynamic&gt; json) {
      return NodoCollection(
          List.from(json[0]).map((object) =&gt;NodoPOJO.fromJson(object)));
    }
  
  
  }
  </code></pre>
  
  <p>class POJO:</p>
  
  <pre><code>class NodoPOJO{
    final String extremo1;
    final String extremo2;
    final String linea;
  
    NodoPOJO(this.extremo1, this.extremo2, this.linea);
  
  
    factory NodoPOJO.fromJson(Map&lt;String, dynamic&gt; json) {
      return NodoPOJO(json[0], json[1],json[2]);
    }
  
  }
  </code></pre>