Unhandled Exception: type '_InternalLinkedHashMap<dynamic, dynamic>' is not a subtyp-CodePudding

I am trying to convert data decoded from json to Map<DateTime,List Here is the Code:

var encodingaccounts = json.decode(gettingAccounts!);
var encodedAccounts = encodingTasks.map((dateTime, Accounts) {
    List<Account> convertedAccountsType = [];
    for (var Account in Accounts) {
      String _summary = Account['summary'];
      String _description = Account['description'];
      String _category = Account['category'];
      bool _isDone = Account['isDone'];
      convertedaccountsType.add(Account(_summary,
          category: _category, description: _description, isDone: _isDone));
    }
    return MapEntry(DateTime.parse(dateTime), convertedaccountsype);
  });
 _accounts = encodedAccounts as Map<DateTime, List<Account>>;

But following error occurs:

 [ERROR:flutter/shell/common/shell.cc(93)] Dart Unhandled Exception: type 
 '_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<DateTime, 
 List<Account>>' in type cast

I have checked encoding.map() returns correct datatype(Map,List) but still this error appears.

CodePudding user response：

You can use Dart special Method of Map.from() Just Like:

_accounts = Map<DateTime,List<Account>>.from(encodedAccounts);

Here is the complete code:

var encodingaccounts = json.decode(gettingAccounts!);
var encodedAccounts = encodingTasks.map((dateTime, Accounts) {
List<Account> convertedAccountsType = [];
for (var Account in Accounts) {
  String _summary = Account['summary'];
  String _description = Account['description'];
  String _category = Account['category'];
  bool _isDone = Account['isDone'];
  convertedaccountsType.add(Account(_summary,
      category: _category, description: _description, isDone: _isDone));
}
return MapEntry(DateTime.parse(dateTime), convertedaccountsype);
});
w_accounts = Map<DateTime,List<Account>>.from(encodedAccount);

CodePudding user response：

It sometimes helps to add types to map as here:

  final _accounts =
      et.map<DateTime, List<Account>>((dateTime, accounts) => MapEntry(
          DateTime.parse(dateTime),
          accounts
              .map<Account>((e) => Account(
                    e['summary'],
                    e['category'],
                    e['description'],
                    e['isDone'],
                  ))
              .toList()));

  print(_accounts.runtimeType);

Prints _InternalLinkedHashMap<DateTime, List<Account>> as expected. (Note that I changed the constructor of Account for simplicity in this example.)