Flutter - type 'List<dynamic>' is not a subtype of type 'Map<dynamic, dynamic>'

Question

I'm just new in flutter and I think this is a newbie question.

I'm trying to get the data that I call on my API and save it to my model but it's having an error type 'List' is not a subtype of type 'Map<dynamic, dynamic>'

Here is the copy of my model

class AdTemplate{
  final int id; 
  final String filePath; 
  final String notification; 
  final String status; 
  final int whenAdded; 

  AdTemplate(
      {this.id, 
      this.filePath, 
      this.notification,
      this.status, 
      this.whenAdded});

  factory AdTemplate.fromJson(Map<String, dynamic> json) {
    return  AdTemplate(
      id: json['ID'], 
      filePath: json['FilePath'],
      notification: json['Notification'], 
      status: json['Status'], 
      whenAdded: json['WhenAdded']
    );
  }
}

And this is my function

Future<AdTemplate> getActiveBannerNotif() async {  
    try { 
      String url = 'https://api/path/'; 
      var res = await http.get(url);  
      final Map data = convert.jsonDecode(res.body);

      if (res.statusCode == 200) { 
        print("Data Fetch!");    
        AdTemplate template = AdTemplate.fromJson(data);  

        return template;
      } else {
        print('No data.'); 

        return null;
      }
    } catch (e) {
      print(e);
      return null;
    } 
}

This is the sample data that I get from the API

[{"ID":49,"FilePath":"20210903t171244.png","Notification":"ACT","WhenAdded":1630689165,"Status":"INA"}]

@MiguelEscobarCalderon this line AdTemplate template = AdTemplate.fromJson(data); — Tony Stark
– Tony Stark, Commented Oct 13, 2021 at 15:36
your receiving an array. that causes the error. change your API or code — rosh-dev851
– rosh-dev851, Commented Oct 13, 2021 at 15:43

Idriss · Accepted Answer · 2021-10-13 15:30:02Z

1

API returns JSON array not json object so that is List not Map.

try :

if (res.statusCode == 200) { 
    print("Data Fetch!");    
    AdTemplate template = AdTemplate.fromJson(json.decode(utf8.decode(res.bodyBytes)));  

    return template;
  }

answered Oct 13, 2021 at 15:30

Idriss

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2 Comments

Tony Stark Over a year ago

I tried your suggestion but its the same error type 'List<dynamic>' is not a subtype of type 'Map<String, dynamic>'

Idriss Over a year ago

show me all the new code (getActiveBannerNotif)

rosh-dev851 · Accepted Answer · 2021-10-13 16:22:28Z

0

You are receiving an array from your API and that causes the error. change as following to access a single element from array

Future<AdTemplate> getActiveBannerNotif() async {  
    try { 
      String url = 'https://api/path/'; 
      var res = await http.get(url);  
      
      if (res.statusCode == 200) { 
        print("Data Fetch!");  
        final data = convert.jsonDecode(res.body);
        AdTemplate template = AdTemplate.fromJson(data[0]);  

        return template;
      } else {
        print('No data.'); 

        return null;
      }
    } catch (e) {
      print(e);
      return null;
    } 
}

edited Oct 13, 2021 at 16:22

answered Oct 13, 2021 at 15:54

rosh-dev851

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Comments

Maikzen · Accepted Answer · 2021-10-14 10:36:10Z

0

Your api return a List

[{"ID":49,"FilePath":"20210903t171244.png","Notification":"ACT","WhenAdded":1630689165,"Status":"INA"}]

Try to get data like that: data[0] or data.first before convert into model

answered Oct 14, 2021 at 10:36

Maikzen

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