Dart Basics for Flutter Developers

June 20, 2025

🐦 Dart Basics for Flutter Developers

Dart is the programming language used to build Flutter apps. If you’re a Flutter developer, understanding Dart is essential for writing clean, efficient, and scalable apps.

This guide covers the core Dart concepts every Flutter developer should know.

📦 1. Variables and Data Types

Dart is statically typed, but it also supports type inference.

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var name = 'Alice'; // Dart infers this as a String

int age = 30;

double height = 5.9;

bool isLoggedIn = true;

String city = 'London';

You can also use dynamic if the type may change:

dart

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dynamic something = 'Hello';

something = 42; // Still valid

🔁 2. Control Flow (if, else, loops)

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if (age > 18) {

print('Adult');

} else {

print('Minor');

}

for (var i = 0; i < 5; i++) {

print(i);

}

while (isLoggedIn) {

// do something

isLoggedIn = false;

}

🧰 3. Functions

Functions are first-class citizens in Dart, and you can define them with or without return types.

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void greet(String name) {

print('Hello, $name!');

}

int add(int a, int b) {

return a + b;

}

Arrow syntax for one-liners:

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int multiply(int x, int y) => x * y;

Optional and named parameters:

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void greetUser(String name, {String title = 'Mr./Ms.'}) {

print('Hello, $title $name');

}

🧱 4. Classes and Objects

Dart is an object-oriented language.

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class Person {

String name;

int age;

Person(this.name, this.age);

void sayHello() {

print('Hi, I’m $name and I’m $age years old.');

}

void main() {

var p = Person('Alice', 30);

p.sayHello();

}

📦 5. Collections (Lists, Maps, Sets)

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// List

List<String> fruits = ['Apple', 'Banana', 'Mango'];

// Map

Map<String, int> scores = {

'Alice': 90,

'Bob': 85,

};

// Set

Set<String> cities = {'London', 'Paris', 'New York'};

Spread operator and conditionals inside collections:

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var list = [1, 2, 3];

var more = [...list, if (true) 4]; // [1, 2, 3, 4]

⚙️ 6. Null Safety

Dart has null safety, which helps avoid null errors.

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String? name; // Can be null

String greeting = name ?? 'Guest'; // Use default if null

Late initialization:

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late String username; // Initialized later but not null

🧵 7. Asynchronous Programming

Flutter apps often use async code to handle I/O.

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Future<void> fetchData() async {

await Future.delayed(Duration(seconds: 2));

print('Data fetched');

}

Using .then():

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fetchData().then((_) => print('Done'));

✅ Conclusion

Mastering Dart is key to becoming a proficient Flutter developer. Its syntax is clean and modern, and it supports both object-oriented and functional programming styles. Once you're comfortable with Dart basics, building rich, responsive UIs with Flutter becomes much easier.

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