type 'List<String>' is not a subtype of type 'String' in type cast

Question

I have this:

List<String> _filters = <String>[8, 11];

I pass this _filters into this endpoint:

this.api.setInterests(token, _filters)
  .then((res) {
    print(res);
  });

which looks like this:

  Future setInterests(String token, List<String> interests) {
    return _netUtil.post(BASE_URL + "/setinterests", body: {
      "token": token,
      "interests": interests
    }).then((dynamic res) {
      return res;
    });
  }

Passing _filters always throws the error:

type 'List<String>' is not a subtype of type 'String' in type cast

I don't know what else dart wants from me.

Check whether token is of type string too. Also try to define _filters with var instead of List<String> and remove <String>. That should be enough for most purposes in Dart. — Bostrot
– Bostrot, Commented Jun 29, 2018 at 22:06
Checked. token is a string. It comes from final token = prefs.getString('token');. Changing to var doesn't fix it. The thing is, the error message makes absolutely no sense, so debugging is vague to even begin with — KhoPhi
– KhoPhi, Commented Jun 30, 2018 at 0:45
Using var throws this back type 'List<dynamic>' is not a subtype of type 'String' in type cast. — KhoPhi
– KhoPhi, Commented Jun 30, 2018 at 0:48
Are you sure that body can take in List's? It looks like it is trying to cast it to a String to me, which obviously does not work. — creativecreatorormaybenot
– creativecreatorormaybenot, Commented Jun 30, 2018 at 7:39

KhoPhi · Accepted Answer · 2018-06-30 11:40:15Z

5

I found the answer. I just added .toString() to the _filters List.

  this.api.setInterests(token, _filters.toString())
  .then((res) {
    print(res);
  });

answered Jun 30, 2018 at 11:40

KhoPhi

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1 Comment

salihgueler Over a year ago

Good to hear that you solved your issue. I was just writing a comment as a friendly reminder. :) First of all, List<String> _filters = <String>[8, 11]; this part is giving an error. This will give us a error below. ` error: The element type 'int' can't be assigned to the list type 'String'. ` I would fix the array the array issue too.

Sanjayrajsinh · Accepted Answer · 2019-09-09 07:08:57Z

3

You need to add json.encode(data) in body
Add these two header
'Content-type': 'application/json',
'Accept': 'application/json',

Create map of your data

final Map<String, dynamic> data = new Map<String, dynamic>();
 data['token'] = token;
 data['interests'] = interests;

Call api like this

http.post(url,<br>
body: json.encode(data),
headers: { 'Content-type': 'application/json',
  'Accept': 'application/json'},
encoding: encoding)
.then((http.Response response) {

     // print(response.toString());

}

answered Sep 9, 2019 at 7:08

Sanjayrajsinh

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