Unhandled Exception: type 'List<dynamic>' is not a subtype of type 'Map<Stri-CodePudding

I send a request to server and when the status code is 200 everything is ok i can decode the returned json, but when the status isn't 200 i have a problem

here's the json of status code 200:

{
    "success": true,
    "statusCode": 200,
    "code": "jwt_auth_valid_credential",
    "message": "Credential is valid",
    "data": {
        "token": "a token",
        "id": 42626,
        "email": "[email protected]",
        "nicename": "",
        "firstName": "",
        "lastName": "",
        "displayName": ""
    }
}

i have adjusted the type of data as a nested structure and it's fine,

the json of else status codes is like this:

{
    "success": false,
    "statusCode": 403,
    "code": "invalid_username",
    "message": "Error: The username ** is not registered on this site. If you are unsure of your username, try your email address instead.",
    "data": []
}

and here's my problem the returned data value is an empty array and idk how to handle it.

here's my model class:

class loginpagemodel{
  late final message;
  late final Data data;
  
  loginpagemodel({
   this.message,required this.data });

  factory loginpagemodel.fromJson(Map<String , dynamic> parsedJson){
    return loginpagemodel(
      message: parsedJson['message'],
      data: Data.fromJson(parsedJson['data']
      ),
    );
  }
}

class Data{
  late final id;
  late final displayName;

  Data({this.id,this.displayName});

  factory Data.fromJson(Map<String,dynamic> parsedJson){
    return Data(
      id: parsedJson['id'],
      displayName: parsedJson['displayName'],
    );
  }
}

Thanks for ur answers in advance.

CodePudding user response：

The problem is when the status code isnt 200 the data field is List. A possible solution:

factory loginpagemodel.fromJson(Map<String , dynamic> parsedJson){
  return loginpagemodel(
    message: parsedJson['message'],
    data: Data.fromJson(
      parsedJson['data'] == []?       // if data is [] (the status code isnt 200)
                                {} :  // empty map
                                parsedJson['data'] // the data field
    ),
  );
}

CodePudding user response：

You can basically control your data, if it is not empty, you can use. Just one example;

if(myJson["data"].length == 0 ) {
print("there is no data");
}else{
print("there is data: ${myJson["data"].toString()}");
}

CodePudding user response：

You could make data field nullable: Data? data.