dart-expert

Dart & Flutter Expert

Expert guidance for Dart programming, Flutter framework, mobile development, and cross-platform applications.

Core Concepts

Dart Language

• Strong typing with type inference
• Async/await and Futures
• Streams
• Mixins and extensions
• Null safety
• Collections

Flutter Framework

• Widgets (Stateless & Stateful)
• State management (Provider, Riverpod, Bloc)
• Navigation and routing
• Material and Cupertino design
• Responsive layouts
• Platform integration

Dart Fundamentals

// Variables and types
var name = 'John';  // Type inference
String explicitType = 'Explicit';
final constantValue = 42;  // Runtime constant
const compileConstant = 'Compile-time';

// Null safety
String? nullableString;
String nonNullable = 'Never null';

// Late initialization
late String lateInit;

// Collections
List<String> names = ['Alice', 'Bob', 'Charlie'];
Map<String, int> ages = {'Alice': 25, 'Bob': 30};
Set<int> uniqueNumbers = {1, 2, 3, 3};  // {1, 2, 3}

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

// Named parameters
void createUser({
  required String name,
  int age = 18,
  String? email,
}) {
  print('Creating user: $name, age: $age');
}

// Classes
class User {
  final String id;
  final String name;
  int age;

  User({
    required this.id,
    required this.name,
    this.age = 0,
  });

  // Named constructor
  User.guest() : this(id: 'guest', name: 'Guest');

  // Methods
  void celebrateBirthday() {
    age++;
  }

  @override
  String toString() => 'User($name, $age)';
}

// Mixins
mixin Loggable {
  void log(String message) {
    print('[${DateTime.now()}] $message');
  }
}

class LoggableUser extends User with Loggable {
  LoggableUser({required String id, required String name})
      : super(id: id, name: name);
}

// Extensions
extension StringExtensions on String {
  bool get isValidEmail => contains('@') && contains('.');
  String capitalize() => '${this[0].toUpperCase()}${substring(1)}';
}

Async Programming