CODEWITHSUNDEEP
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Muhammad Hassan
Muhammad Hassan

Reputation: 1304

Flutter Casting a Map<String, dynamic> to Future<Map<String, dynamic>> forcefully returns Error

I have a function that contains some Future returns as show below.

Future<Map<String, dynamic>> myFunction() {
  if(some_condition){
    returnFromThisFunc = {
        'status': false,
        'message':'Some message',
        'data': {}
    } as Future<Map<String, dynamic>>;    // Error mentioning this line at 'as'
  } else {
    // Returning "Future<Map<String, dynamic>> returnFromThisFunc" return from some API and etc functions that are working fine.
  }
  return returnFromThisFunc;
}

Now the problem is that if my some_condition is false then it is working fine and function is returning the data but when some_condition is true then it is giving me this error Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Future<Map<String, dynamic>>' in type cast

How to fix this and return Future<Map<String, dynamic>> in any way...???

Upvotes: 0

Views: 805

Answers (3)

My Car
My Car

Reputation: 4576

Try the following code:

Future<Map<String, dynamic>> myFunction() {
  if(some_condition){
    returnFromThisFunc = {
        'status': false,
        'message':'Some message',
        'data': {}
    }
  } else {
    // Returning "Future<Map<String, dynamic>> returnFromThisFunc" return from some API and etc functions that are working fine.
  }
  return Future.value(returnFromThisFunc); // <= add this
}

Feel free to comment me if you have any questions.

Upvotes: 1

eamirho3ein
eamirho3ein

Reputation: 17940

When your function return type is Future you should use await in it, but when you don't have any async method in it, you should use Future.value for returning value. try this:

Future<Map<String, dynamic>> myFunction() {
  if(some_condition){
    returnFromThisFunc = {
        'status': false,
        'message':'Some message',
        'data': {}
    }
  } else {
    // Returning "Future<Map<String, dynamic>> returnFromThisFunc" return from some API and etc functions that are working fine.
  }
  return Future.value(returnFromThisFunc) ;/// <--- add this
}

Upvotes: 1

Md. Yeasin Sheikh
Md. Yeasin Sheikh

Reputation: 63709

You can use Future.value on return.

Future<Map<String, dynamic>> myFunction() {
  Map<String, dynamic> returnFromThisFunc;
  if (1 < 2) {
    returnFromThisFunc = {
      'status': false,
      'message': 'Some message',
      'data': {}
    }; 
  } else {
    returnFromThisFunc = {};
  }
  return Future.value(returnFromThisFunc);
}

Upvotes: 1

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