Class

 

class with a constructor

class Fruit {
  String type;
// Constructor - Same name as class
  Fruit(this.type);
}

void main() {
  Fruit fruit = Fruit('apple');
  print(fruit.type);
}

named parameters

class Fruit {
  String type;
// Constructor - Same name as class
  Fruit({this.type}); //new
}

void main() {
  Fruit fruit = Fruit(type: 'Apple'); //new
  print(fruit.type);
}

class that does not define a constructor

class BaristaNoConstructor {
  String name;
  int experience;
}

void main() {
  BaristaNoConstructor baristaNoConstructor = BaristaNoConstructor();
  baristaNoConstructor.experience = 10;
  print('baristaNoConstructor.experience: ${baristaNoConstructor.experience}');
// baristaNoConstructor.experience: 10
}

class that defines a constructor with named parameters

class BaristaWithConstructor {
  String name;
  int experience;
// Constructor - Named parameters by using { }
  BaristaWithConstructor({this.name, this.experience});
// Method - return value
  int whatIsTheExperience() {
    return experience;
  }
}

void main() {
// Class Named Constructor and return value
  BaristaWithConstructor barista = BaristaWithConstructor(name: 'Sandy', experience: 10);
  int experienceByProperty = barista.experience;
  int experienceByFunction = barista.whatIsTheExperience();
  print('experienceByProperty: $experienceByProperty');
  print('experienceByFunction: $experienceByFunction');
// experienceByProperty: 10
// experienceByFunction: 10
}

defines a named constructor

class BaristaNamedConstructor {
  String name;
  int experience;
  // Constructor - Named parameters { }
  BaristaNamedConstructor({this.name, this.experience});
// Named constructor - baristaDetails - With named parameters
  BaristaNamedConstructor.baristaDetails({this.name, this.experience});
}

void main() {
  BaristaNamedConstructor barista = BaristaNamedConstructor.baristaDetails(name:
  'Sandy', experience: 10);
  print('barista.name: ${barista.name} - barista.experience: ${barista.experience}');
// barista.name: Sandy - barista.experience: 10
}

Class Inheritance

class BaristaNamedConstructor {
  String name;
  int experience;
  // Constructor - Named parameters { }
  BaristaNamedConstructor({this.name, this.experience});
// Named constructor - baristaDetails - With named parameters
  BaristaNamedConstructor.baristaDetails({this.name, this.experience});
}

// Class inheritance
class BaristaInheritance extends BaristaNamedConstructor {
  int yearsOnTheJob;
  BaristaInheritance({this.yearsOnTheJob}) : super();
}

void main() {
// Init Inherited Class
  BaristaInheritance baristaInheritance = BaristaInheritance(yearsOnTheJob: 7);
// Assign Parent Class variable
  baristaInheritance.name = 'Sandy';
  print('baristaInheritance.yearsOnTheJob: ${baristaInheritance.yearsOnTheJob}');
  print('baristaInheritance.name: ${baristaInheritance.name}');
}