Dart/Flutter: How to write setter and getter fields or members variables in a class with Example

Setters and Getters allow you to read and update the data of a class object. It uses to achieve encapsulation

#Dart setter and getter examples

In classes, Getters provide an access to read instance member variables. Setters allow you to update the instance variables of a class.

Getters are called accessors, and Setters are known as Mutators.

In Dart, Getter and Setters are implicitly defined for every member declared in a class Still, You can customize the fields to write setters and getters

Getter’s syntax:

datatype get member_name{
// code to return members
}

Setters Syntax:

set  member_name{
// code to update members
}

Here is an example code

• First, Declare fields or member variables in a class with the type
• provide setter and Getter methods with set and get keyword
• Can access getter using an instance of a class assign the value to class field instance.field=value.
• Getter can be accessed using instance.field.

Here is an example program

class Employee {
  int _eid;
  String _name;

  int get id {
    return _eid;
  }

  set id(int eid) {
    _eid = eid;
  }

  String get name {
    return _name;
  }

  set name(String name) {
    _name = name;
  }
}

void main() {
  Employee emp = Employee();
  emp.id = 12;
  emp.name = "john";

  print("${emp.id} - ${emp.name}");
}

Output:

12 - john

Similarly, You can rewrite the getter methods with shorter syntax. arrow(=>) function to replace an existing function with a shorter syntax expression.

  int get id => _eid;

Here is an example program

class Employee {
  int _eid;
  String _name;

  int get id => _eid;

  set id(int eid) {
    _eid = eid;
  }

  String get name => _name;

  set name(String name) {
    _name = name;
  }
}

void main() {
  Employee emp = Employee();
  emp.id = 12;
  emp.name = "john";

  print("${emp.id} - ${emp.name}");
}

Similarly, can use setters and getters for private members in the library.