How to Check if string is empty/Null in flutter

Hi Guy’s Welcome to Proto Coders Point, In this Flutter dart article let’s learn how to validate a String Variable to check if the given String is empty or null.

Suppose, You are building an application where you ask user to enter some data & you don’t accept empty or null value.

At situation, we need to check if string is empty or null, Let’s Start:

Function to check of String is null or empty

Will create a function/method that will validate our string, Let’s name the function as stringValidator()

bool stringvalidator(String? value) {
  if (value == null) {
    return false;
  }

  if (value.isEmpty) {
    return false;
  }

  return true;
}

Let’s make the above function shorter by using ternary operation in dart.

bool stringvalidator(String? value) {
   return value?.isNotEmpty ?? false;
}

The above function, return true if String variable contain atleast one character, else return false if string is empty or null.

Complete Code – To check if string variable is empty or null in dart Flutter

bool stringvalidator(String? value) {
   return value?.isNotEmpty ?? false;
}

void main() {
  print(stringvalidator(''));   // false
  print(stringvalidator('Rajat Palankar'));    // true
  print(stringvalidator(null));   // false
}