CODEWITHSUNDEEP
httpflutterexception
Bala
Bala

Reputation: 1375

Why do i get "Exception:" when i receive the exception message in dart?

Hi I am new to the dart and flutter framework.

I am throwing error like below from my service class where i am calling the API. 

if(res["status"]!=200) throw new Exception("Invalid User");

and receiving in presenter class like below and printing

.catchError((Object error){
      print(error);

});

I am expecting the result as "Invalid User", but am getting with additional word like "Exception: Invalid User". Can you please explain me why this additional word 'Exception' is coming? and how can i get only the string which i am passing.

Upvotes: 23

Views: 10214

Answers (5)

suprim
suprim

Reputation: 31

You can create an extension function in dart as

extension FormattedMessage on Exception {
  String get getMessage {
    if (toString().startsWith("Exception: ")) {
      return toString().substring(11);
    }else {
      return toString();
    }
  }
}

After that you can simply call

exception.getMessage;

to get your exception message without having to implement the Exception class or show the user how the exception is being substring.

Upvotes: 3

Specks Dude
Specks Dude

Reputation: 96

Use ErrorDescription

throw ErrorDescription(response['error']);

It still acts as an error but you don't get the "Exception" infront of the error

Upvotes: 5

Carlos
Carlos

Reputation: 135

Quick solution:

.catchError((error){
  print(
    error.toString().substring(11)
  );
});

You cut the first 11 message chars, that is, "Exception: ".

Upvotes: 2

Shubham Gupta
Shubham Gupta

Reputation: 1997

You can use the message property of the Exception object

.catchError((error){
  print(error.message);

});

This should output Invalid User

I hope this is what you are looking for.

Upvotes: 1

Jitesh Mohite
Jitesh Mohite

Reputation: 34210

Surprisingly that's how written in exception toString code.

 String toString() {
    if (message == null) return "Exception";
    return "Exception: $message";  // your message will be appended after exception. 
  }

If you want to avoid this then you have to create custom exception like below:

class HttpException implements Exception {
  final String message;

  HttpException(this.message);  // Pass your message in constructor. 

  @override
  String toString() {
    return message;
  }
}

Upvotes: 32

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