dart_20 接口

接口方式使用

• 定义人抽象类

abstract class IPerson {
  String name;
  int age;

  IPerson(this.name, this.age);

  String info() {
    return 'Name: $name, Age: $age';
  }
}

接口用途的抽象类 请用字母 I 开头 , 如 IPhone

• 老师

class Teacher implements IPerson {
  @override
  String name;

  @override
  int age;

  Teacher(this.name, this.age);

  @override
  String info() {
    return 'Teacher -> Name: $name, Age: $age';
  }
}

• 学生

class Student implements IPerson {
  @override
  int age;

  @override
  String name;

  Student(this.name, this.age);

  @override
  String info() {
    return 'Student -> Name: $name, Age: $age';
  }
}

• 打印信息

void makePersonInfo(IPerson user) => print(user.info());

• 实例化

void main(List<String> args) {
  var t = Teacher('zhangsan', 99);
  makePersonInfo(t);

  var s = Student('hans', 66);
  makePersonInfo(s);
}

Teacher -> Name: zhangsan, Age: 99
Student -> Name: hans, Age: 66

履行多接口

• 定义学校抽象类

abstract class ISchool {
  int grade;

  ISchool(this.grade);

  String schoolInfo() {
    return 'Grade: $grade';
  }
}

• 学生 多继承

class Student implements IPerson, ISchool {
  @override
  int age;

  @override
  String name;

  @override
  int grade;

  Student(this.name, this.age, this.grade);

  @override
  String info() {
    return 'Student -> Name: $name, Age: $age';
  }

  @override
  String schoolInfo() {
    return 'School -> Name: $name, Age: $age, Grade: $grade';
  }
}

• 打印信息

void makePersonInfo(IPerson user) => print(user.info());
void makeSchoolInfo(ISchool user) => print(user.schoolInfo());

• 实例化

void main(List<String> args) {
  var t = Teacher('zhangsan', 99);
  makePersonInfo(t);

  var s = Student('hans', 66, 5);
  makePersonInfo(s);
  makeSchoolInfo(s);
}

Teacher -> Name: zhangsan, Age: 99
Student -> Name: hans, Age: 66
School -> Name: hans, Age: 66, Grade: 5

从一个普通类履行接口

class Phone {
  void startup() {
    print('开机');
  }

  void shutdown() {
    print('关机');
  }
}

class AndroidPhone implements Phone {
  @override
  void startup() {
    print('AndroidPhone 开机');
  }

  @override
  void shutdown() {
    print('AndroidPhone 关机');
  }
}

void main() {
  var p = AndroidPhone();
  p.startup();
  p.shutdown();
}

Dart 可以从一个普通的类履行接口