抽象

abstract 类、函数、成员

• 普通类前加 abstract

abstract class Person {
  String name = 'ducafecat';
  void printName() {
    print(name);
  }
}

不能直接 new 实例化

var p = Person();
p.printName();

Abstract classes can't be instantiated.
Try creating an instance of a concrete subtype.

继承方式使用

class Teacher extends Person {
}

var p = Teacher();
p.printName();

ducafecat

接口方式使用

定义

abstract class Person {
  String name = '';
  void printName();
}

class Teacher implements Person {
  @override
  String name;

  Teacher(this.name);

  @override
  void printName() {
    print('Teacher: $name');
  }
}

实例

var p = Teacher("ducafecat");
p.printName();

ducafecat