Getters and Setters
Expose computed and guarded properties.
Getters and Setters is a free Dart Academy lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Dart Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Beyond Plain Fields
Sometimes you want a property that is computed or guarded. Dart offers getters and setters to control how a value is read and written.
What a Getter Is
A getter looks like a field from outside but runs code to produce its value. Use the get keyword to define one.
int get area => width * height;Getters Compute Values
A getter is perfect for values derived from other fields. Read it with plain dot notation, no parentheses needed.
class Box {
int w = 2, h = 3;
int get area => w * h;
}Calling a Getter
Access a getter exactly like a field. The code inside runs each time, so it always reflects the latest data.
var b = Box();
print(b.area); // 6What a Setter Is
A setter runs code when you assign a value. Define it with the set keyword and a single parameter to receive the input.
set width(int value) {
_w = value;
}Setters Guard Input
A setter can validate before storing. Reject bad data, clamp ranges, or log changes right inside the assignment.
set age(int v) {
if (v >= 0) _age = v;
}Private Backing Fields
Names starting with an underscore are private to the library. A setter often guards a private backing field like _age.
int _age = 0;
int get age => _age;Calling a Setter
Assign to a setter just like a field with the equals sign. Dart routes that assignment through your guarding code.
var p = Person();
p.age = 25;Getter Without a Setter
Define only a getter to make a read-only property. Outside code can read it but can never assign to it.
String get fullName => "$first $last";Why Getters and Setters
They let you change internal storage later without breaking callers. The public property stays the same while logic hides behind it. 🔐
Computed Property Example
A getter shines for formatting. Combine fields into a friendly string that callers read like any normal property.
String get label => "$name: $score pts";Quick Check
You want a property others can read but never assign. What do you define?
Recap: Getters and Setters
You learned that getters compute and expose values, setters guard assignments, and together they hide internal details cleanly. 🎉
Frequently asked questions
Is the “Getters and Setters” lesson free?
Yes — the full text of “Getters and Setters” is free to read here on the web, and the Dart Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Dart Academy course, upgrade to CoddyKit PRO.
What will I learn in “Getters and Setters”?
Expose computed and guarded properties. You practise Dart Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Dart Academy?
No prior experience is required. Dart Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Getters and Setters” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Dart Academy lesson?
Yes. Every Dart Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.