Dart Basics for Flutter Developers

Dart is the programming language used to build Flutter apps. Understanding Dart fundamentals helps you write better Flutter code.

1. Variables and Data Types

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// Variable declaration

int age = 25;

double price = 19.99;

String name = 'John';

bool isLoggedIn = true;

var city = 'New York';  // type inferred

2. Functions

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// Simple function

int add(int a, int b) {

  return a + b;

}

// Arrow function (short syntax)

int multiply(int a, int b) => a * b;

3. Control Flow

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// If-else

if (age > 18) {

  print('Adult');

} else {

  print('Minor');

}

// For loop

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

  print(i);

}

// While loop

int count = 0;

while (count < 3) {

  print(count);

  count++;

}

4. Collections

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// List

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

// Map (dictionary)

Map<String, int> scores = {'Alice': 90, 'Bob': 85};

// Iterate list

for (var fruit in fruits) {

  print(fruit);

}

5. Classes and Objects

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class Person {

  String name;

  int age;

  Person(this.name, this.age);

  void greet() {

    print('Hello, my name is $name');

  }

}

void main() {

  var p = Person('Alice', 30);

  p.greet();  // Output: Hello, my name is Alice

}

6. Null Safety

Dart is null-safe, meaning variables can’t be null unless explicitly declared nullable.

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int? nullableAge;  // Can be null

int nonNullableAge = 18;  // Cannot be null

7. Asynchronous Programming

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Future<String> fetchData() async {

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

  return 'Data loaded';

}

void main() async {

  print('Fetching...');

  String data = await fetchData();

  print(data);

}

Summary

Concept Example

Variables int age = 25;

Functions int add(int a, int b) => a + b;

Control Flow if-else, for, while loops

Collections List, Map

Classes class Person { ... }

Null Safety int? nullableAge;

Async/Await Future, async/await

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