Extract Data from JSON Array in Flutter/Dart

Question

This is the response from request.

var response = [{"id":4731},{"id":4566},{"id":4336},{"id":4333},{"id":4172},{"id":4170},{"id":4168},{"id":4166},{"id":4163},{"id":4161}];

How to extract ids and store in List of int using flutter. I have try this code but not working.

Future<List<int>> fetchTopIds() async{

     final response = await client.get('$_baseUrl/posts?fields=id');
     final ids = json.decode(response.body); 
     return ids.cast<int>();
}

Solution 1

This should do what you want:

var intIds = ids.map<int>((m) => m['id'] as int).toList();

Solution 2

This is what I did when got "array of object" as response (I know I'm late. But it will help the next guy)

    List list = json.decode(response.body);

  if (response.body.contains("id")) {
    var lst = new List(list.length);

    for (int i = 0; i < list.length; i++) {
      var idValue = list[i]['id'];
      print(idValuee);
    }