JSON_Encode_Decode.dart

class MyListClass{
  String value;
  List<MyItemClass> items;

  MyListClass(){}

  MyListClass.fromRaw(Map value){
    value = JSON.decode(value['value']);
    items = JSON.decode(value['items'],reviver:(k,v){
      if(v is Map)                        //Parse every Map found as a MyItemClass
        return new MyItemClass.fromRaw(v);
      return v;                           //Return every other object as they are (list, properties...)
    });
  }

  Map toJson() {
    return{
        'value':JSON.encode(value),
        'items':JSON.encode(items,toEncodable: (v){
          if(v is MyItemClass)
            return v.toJson();
          return v;
        })
    };
  }
}


class MyItemClass{
  String val1;
  String val2;

  Contact(){}

  MyItemClass.fromRaw(Map value){
    val1 = JSON.decode(value['val1']);
    val2 = JSON.decode(value['val2']);
  }

  Map toJson() {
    return{
        'val1':JSON.encode(val1), 
        'val2':JSON.encode(val2)
    };
  }
}