在获取有关人员的信息后，显示他们的清单，Java，GUI

Question

我有一堂课叫做“人”：

    package personFiles;

    public class Person {

       private int id;
       private String name;
       private String surname;
       private int age;
       private String gender;

       public int getID() {
         return id;
       }

       public void setID(int id) {
         this.id = id;
       }

       public String getName() {
         return name;
       }

       public void setName(String name) {
         this.name = name;
       }

       public String getSurname() {
         return surname;
       }

       public void setSurname(String surname) {
         this.surname = surname;
       }

       public int getAge() {
         return age;
       }

       public void setAge(int age) {
         this.age = age;
       }

       public String getGender() {
         return gender;
       }

       public void setGender(String gender) {
         this.gender = gender;
       }

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

      public String toString() {
        return id + "; " + name + "; " + surname + "; " + age + "; " + gender;
      }
   }

而且我希望能够将一个人添加到随后应显示的数组中。 到目前为止，我编写的代码如下：

package personFiles;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;


@SuppressWarnings("serial")
public class Osoblje extends JFrame {
    private JTextArea outputJTA = new JTextArea("");
    private JScrollPane outputJTAScrollPane = new JScrollPane(outputJTA);
    private JLabel idJL = new JLabel();
    private JLabel nameJL = new JLabel();
    private JTextField idJTF = new JTextField();
    private JTextField nameJTF = new JTextField();
    private JLabel surnameJL = new JLabel();
    private JLabel ageJL = new JLabel();
    private JTextField surnameJTF = new JTextField();
    private JTextField ageJTF = new JTextField();
    private JLabel genderJL = new JLabel();
    private JTextField genderJTF = new JTextField();
    private JButton newPersonJB = new JButton();
    private JButton pokaziJB = new JButton();

    Person[] personList = new Person [];

    public Osoblje(String title) { 
        // Frame-Initialisierung
        super(title);
        setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        int frameWidth = 310; 
        int frameHeight = 269;
        setSize(frameWidth, frameHeight);
        Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
        int x = (d.width - getSize().width) / 2;
        int y = (d.height - getSize().height) / 2;
        setLocation(x, y);
        setResizable(false);
        Container cp = getContentPane();
        cp.setLayout(null);
        // Anfang Komponenten

        outputJTAScrollPane.setBounds(8, 8, 129, 217);
        cp.add(outputJTAScrollPane);
        idJL.setBounds(152, 16, 51, 19);
        idJL.setText("ID:");
        cp.add(idJL);
        nameJL.setBounds(152, 40, 54, 20);
        nameJL.setText("Name:");
        cp.add(nameJL);
        idJTF.setBounds(208, 16, 65, 17);
        cp.add(idJTF);
        nameJTF.setBounds(208, 40, 65, 17);
        cp.add(nameJTF);
        surnameJL.setBounds(152, 64, 59, 19);
        surnameJL.setText("Surname:");
        cp.add(surnameJL);
        ageJL.setBounds(152, 88, 51, 19);
        ageJL.setText("Age:");
        cp.add(ageJL);
        surnameJTF.setBounds(208, 64, 65, 17);
        cp.add(surnameJTF);
        ageJTF.setBounds(208, 88, 65, 17);
        cp.add(ageJTF);
        genderJL.setBounds(152, 112, 59, 19);
        genderJL.setText("Gender:");
        cp.add(genderJL);
        genderJTF.setBounds(208, 112, 65, 17);
        cp.add(genderJTF);
        newPersonJB.setBounds(152, 144, 121, 25);
        newPersonJB.setText("nova osoba");
        newPersonJB.setMargin(new Insets(2, 2, 2, 2));
        newPersonJB.addActionListener(new ActionListener() { 
            public void actionPerformed(ActionEvent evt) { 
                newPersonJB_ActionPerformed(evt);
            }
        });
        cp.add(newPersonJB);
        pokaziJB.setBounds(152, 184, 121, 25);
        pokaziJB.setText("pokazi");
        pokaziJB.setMargin(new Insets(2, 2, 2, 2));
        pokaziJB.addActionListener(new ActionListener() { 
            public void actionPerformed(ActionEvent evt) { 
                pokaziJB_ActionPerformed(evt);
            }
        });
        cp.add(pokaziJB);
        // Ende Komponenten

        setVisible(true);
    } // end of public Osoblje

    // Anfang Methoden

    public static void main(String[] args) {
        new Osoblje("Osoblje");
    } // end of main

    public void newPersonJB_ActionPerformed(ActionEvent evt) {
        personList[i] = new Person(idJTF.getText(), nameJTF.getText(), surnameJTF.getText(), ageJTF.getText(), genderJTF.getText()); //create new person
    } // end of newPersonJB_ActionPerformed

    public void pokaziJB_ActionPerformed(ActionEvent evt) {
        outputJTA.setText("PersonID; Name; Surname; Age; Gender \n" + personList[i] + "\n"); //display personList
    } // end of pokaziJB_ActionPerformed

}

，但有两个问题：

1. 声明personList时必须在方括号中输入哪个数字？
2. 我必须输入哪个号码？

谢谢！

Answer 1

代替

Person[] personList = new Person [];

采用

List<Person> personList = new ArrayList<>();

您可以按以下方式添加人员

personList.add(new Person(...));

使用列表而不是数组可以解决在初始化变量时必须指定大小的问题。