Dart Getters and Setters

1. What are Getters and Setters? (Programming Definition)

Getters and setters are special methods in Dart that allow you to read (get) or change (set) the values of private variables in a controlled way.

- A getter lets you access the value of a variable as if it were a property.
- A setter lets you update the value of a variable but with control over how it changes.

2. Real-World Example of Getters and Setters

Imagine you have a treasure box that holds your favorite toys. You don’t want just anyone to take toys or put broken toys inside. So, you have a getter to look inside the box safely and a setter that checks toys before letting you put them in.

3. Important Terms

• private variable: A variable that can only be accessed inside its own class (starts with _ in Dart).
• getter: A method that gets (reads) the value of a variable.
• setter: A method that sets (writes) the value of a variable.

4. How to Use Getters and Setters in Dart

class Person {
  // private variable (underscore means private)
  String _name;

  Person(this._name);

  // Getter to read _name
  String get name {
    return _name;
  }

  // Setter to change _name with control
  set name(String newName) {
    if (newName.isNotEmpty) {
      _name = newName;
    } else {
      print('Name cannot be empty!');
    }
  }
}

void main() {
  var person = Person('Alice');

  // Using getter
  print(person.name); // Output: Alice

  // Using setter
  person.name = 'Bob';
  print(person.name); // Output: Bob

  // Trying to set an empty name
  person.name = '';
  // Output: Name cannot be empty!
  print(person.name); // Output: Bob (unchanged)
}

Explanation:

• We keep _name private so it can't be changed directly from outside.
• get name lets us read the name like a property.
• set name lets us update the name, but only if the new name is not empty.

5. Why Use Getters and Setters?

• Protect your data by controlling how variables are read or changed.
• Run extra code when values are accessed or updated (like validations).
• Make your code cleaner and easier to maintain.

6. Summary

Getters and setters in Dart help you safely access and modify private variables, just like having special doors to your treasure box that check what goes in or out.