Dart – Getters and Setters

Getters and Setters, also called accessors and mutators, allow the program to initialize and retrieve the values of class fields respectively. 

• Getters or accessors are defined using the get keyword.
• Setters or mutators are defined using the set keyword.

A default getter/setter is associated with every class. However, the default ones can be overridden by explicitly defining a setter/ getter. A getter has no parameters and returns a value, and the setter has one parameter and does not return a value.

Syntax: Defining a getter
 
Return_type  get identifier  
{  
    // statements
}  

Syntax: Defining a setter
 
set identifier  
{  
   // statements
}

Example 1:

The following example shows how you can use getters and setters in a Dart class:

Dart

// Dart Program in Dart to illustrate
// getters and setters #GFG
class Student {
   String name;
   int age;

   String get stud_name {
      return name;
   }

   void set stud_name(String name) {
      this.name = name;
   }

   void set stud_age(int age) {
      if(age<= 0) {
        print("Age should be greater than 5");
      }  else {
         this.age = age;
      }
   }

   int get stud_age {
      return age;
   }
}
void main() {
   Student s1 = new Student();
   s1.stud_name = 'Nitin';
   s1.stud_age = 0;
   print(s1.stud_name);
   print(s1.stud_age);
}

Output:

Age should be greater than 5  
Nitin
Null 

Example 2:

Dart

// Dart program in Dart to illustrate
// getters and setters #GFG
void main() {
  var cat = new Cat();

  // Is cat hungry? true
  print("Is cat hungry? ${cat.isHungry}");

  // Is cat cuddly? false
  print("Is cat cuddly? ${cat.isCuddly}");

  print("Feed cat.");
  cat.isHungry = false;

  // Is cat hungry? false
  print("Is cat hungry? ${cat.isHungry}");

   // Is cat cuddly? true
  print("Is cat cuddly? ${cat.isCuddly}");
}

class Cat {
  bool _isHungry = true;

  bool get isCuddly => !_isHungry;

  bool get isHungry => _isHungry;
  bool set isHungry(bool hungry) => this._isHungry = hungry;
}

Output: