android studio定义一个子类Student，继承Person类，并写一个main（），实现对该子类及其父类的调用

好的，下面是实现的代码：

// Person类
public class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public void sayHello() {
        System.out.println("Hello, my name is " + name + ". I'm " + age + " years old.");
    }
}

// Student类继承Person类
public class Student extends Person {
    private String school;

    public Student(String name, int age, String school) {
        super(name, age);
        this.school = school;
    }

    public void saySchool() {
        System.out.println("I'm studying at " + school);
    }
}

// 主函数
public class Main {
    public static void main(String[] args) {
        Person person = new Person("Lucy", 20);
        person.sayHello();

        Student student = new Student("Tom", 18, "Beijing University");
        student.sayHello();
        student.saySchool();
    }
}

运行上述代码，输出如下：

Hello, my name is Lucy. I'm 20 years old.
Hello, my name is Tom. I'm 18 years old.
I'm studying at Beijing University

可以看出，子类Student继承了父类Person的方法和属性，并且还添加了自己的方法和属性。在主函数中，我们分别创建了一个Person对象和一个Student对象，并调用它们的方法。