将简单的枚举传递给Java中的构造函数

Question

I am trying to learn Java. I would like to have a enum as a parameter in the constructor. But I am getting an error.

public class Person {

    private int age, weight, height;
    private String name;

    private enum gender {MALE, FEMALE}

    public Person(int age, int weight, int height, String name, enum gender) {
         this.age    = age;
         this.weight = weight;
         this.height = height;
         this.name   = name;
         this.gender = gender;
    }
}

How would I handle the gender? I've tried with just gender and that didn't work either.

Answer 1

First, you need to create field of type gender ...

private gender aGender;

Then you need to change the constructor to take a reference to an object of type gender

public Person(int age, int weight, int height, String name, gender aGender) {

Then you need to assign the parameter to your field...

this.aGender = aGender;

You gender enum should also be public

public enum gender {
    MALE, FEMALE
}

Otherwise, no one will be able to use it

For example...

public class Person {

    private int age, weight, height;
    private String name;
    private gender aGender;

    public enum gender {
        MALE, FEMALE
    }

    public Person(int age, int weight, int height, String name, gender aGender) {
                 this.age = age;
        this.weight = weight;
        this.height = height;
        this.name = name;
        this.aGender = aGender;
    }
}

You might like to have a read through Code Conventions for the Java TM Programming Language , it will make it easier for people to read your code and for you to read others

Answer 2

如果您定义了enum Gender ，则可以直接将Gender传递给构造函数，更改为

public Person(int age, int weight, int height, String name, Gender gender)

Answer 3

The enum type you defined has name gender , therefore you need to pass it as

gender eGender

Just a comment. By the convention all the self defined types (class names, interface names, enum names) should begin with a capital letter.

So in this case it would be better if you named your enum type like this.

private enum Gender {MALE, FEMALE}