Exception Handling trong Dart (try-catch)

void main() {
  try {
    int result = 10 ~/ 0;  // Integer division by zero
    print(result);
  } catch (e) {
    print('Error: $e');
  }
}

void main() {
  try {
    var list = [1, 2, 3];
    print(list[10]);  // RangeError
  } on RangeError {
    print('Index out of range');
  } on FormatException {
    print('Format error');
  } catch (e) {
    print('Unknown error: $e');
  }
}

void main() {
  try {
    throw Exception('Something went wrong');
  } catch (e, stackTrace) {
    print('Error: $e');
    print('Stack trace: $stackTrace');
  }
}

void main() {
  try {
    print('Opening file...');
    throw Exception('File not found');
  } catch (e) {
    print('Error: $e');
  } finally {
    print('Cleaning up...');  // Luôn chạy
  }
}

void validateAge(int age) {
  if (age < 0) {
    throw ArgumentError('Age cannot be negative');
  }
  if (age > 150) {
    throw RangeError('Age seems unrealistic');
  }
}
 
void processAge(int age) {
  try {
    validateAge(age);
  } catch (e) {
    print('Logging error: $e');
    rethrow;  // Ném lại exception
  }
}

class AuthException implements Exception {
  final String message;
  AuthException(this.message);
  
  @override
  String toString() => 'AuthException: $message';
}
 
class NetworkException implements Exception {
  final int statusCode;
  final String message;
  
  NetworkException(this.statusCode, this.message);
  
  @override
  String toString() => 'NetworkException($statusCode): $message';
}
 
void login(String username, String password) {
  if (username.isEmpty) {
    throw AuthException('Username is required');
  }
  if (password.length < 6) {
    throw AuthException('Password too short');
  }
}

Future<String> fetchData() async {
  await Future.delayed(Duration(seconds: 1));
  throw Exception('Network error');
}
 
Future<void> main() async {
  try {
    var data = await fetchData();
    print(data);
  } on Exception catch (e) {
    print('Failed to fetch: $e');
  }
}

// FormatException - parsing error
int.parse('abc');
 
// RangeError - index out of bounds
[1, 2, 3][10];
 
// ArgumentError - invalid argument
Uri.parse('');
 
// StateError - invalid state
[].first;
 
// UnsupportedError - operation not supported
List.unmodifiable([1, 2]).add(3);

// ✅ Catch specific exceptions
try {
  // code
} on FormatException {
  // handle
} on IOException {
  // handle
}
 
// ❌ Tránh catch chung chung
try {
  // code
} catch (e) {
  // không biết loại lỗi
}
 
// ✅ Sử dụng finally cho cleanup
var file = openFile();
try {
  processFile(file);
} finally {
  file.close();
}