[Flutter] Dart 문법 (상속)

 

 

 

* 상속

		

			
			
			
		
class Spacecraft {
  String? name;
  DateTime? launchDate;

  //Constructor, with syntactic sugar for assignment to members.
  Spacecraft(this.name, this.launchDate) {
    //Initialization code goes here.
  }

  Spacecraft.origin() {
    name = "무탈리스크";
    launchDate = DateTime.now();
  }

  //Named contructor that forwards to the default one.
  Spacecraft.unlaunched(String name) : this(name, null);

  int? get launchYear => launchDate?.year; //read-only non-final property

  //Method
  void describe() {
    print('Spacecraft: $name');
    if (launchDate != null) {
      int years = DateTime.now().difference(launchDate!).inDays ~/ 365;
      print('Launched: $launchYear ($years years ago)');
    } else {
      print('Unlaunched');
    }
  }
}

class Orbiter extends Spacecraft {
  num altitude;
  Orbiter(String name, DateTime launchDate, this.altitude)
      : super(name, launchDate);
}

void main() {
  Orbiter ob = Orbiter("히드라", DateTime.now(), 50);
  ob.describe();
}

		

			
			
			
		
//결과
Spacecraft: 히드라
Launched: 2021 (0 years ago)

 

 

+ 추가 상속(mixin) : with 이용. 여러 클래스 계층에서 클래스의 코드를 재사용하는 방법

		

			
			
			
		
class Work {
  var money;
}

class Student {
  var year;
}

class School {
  var name = "elementary school";
}

class People extends Work with Student {}

class People2 extends Work with Student, School {}

void main() {
  People p = People();
  p.year = 2019;
  p.money = 20000;
  print(p.year);
  print(p.money);

  People2 p2 = People2();
  print(p2.name);
}

		

			
			
			
		
//결과
2019
20000
elementary school

 

---

같이 보면 좋은 포스팅

https://cording-cossk3.tistory.com/84

[Flutter] Dart 문법 (abstract, implement)

https://cording-cossk3.tistory.com/85

[Flutter] Dart 문법 (async, Future, await, then)

https://cording-cossk3.tistory.com/86

[Flutter] Dart 문법 (getter, setter)

https://cording-cossk3.tistory.com/87

[Flutter] Dart 문법 (json)

https://cording-cossk3.tistory.com/88

[Flutter] Dart 문법 (skip, take)