java - Java JList およびリストの問題

Question

リスト項目を JList に追加しました

numbersList.add("first example");
numbersList.add("second example");
numbersList.add("third example");

新しいテキストまたは数値をフィールドに追加すると、リストに追加されて JList に表示されます。ここで私のコードは、ボタンを押すと、 textfield から追加されたfullListリストからJList に新しい要素が表示されるようにしたいだけです。 numberListnumberTxtFld

ps 不要なコードをいくつか削除しました。

package average;

import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.ListSelectionModel;

public class Surface extends JLabel{
    private JTextField numberTxtFld;
    private JLabel topLabel;
    private JLabel sumLabel;
    private JLabel avgLabel;
    private JLabel maxLabel;
    private JLabel minLabel;
    private JLabel amountLabel;
    private JLabel listLabel;
    private JLabel resultLabel;
    private JLabel sumAnswerFld;
    private JLabel avgAnswerFld;
    private JLabel maxAnswerFld;
    private JLabel minAnswerFld;
    private JLabel amountAnswerFld;
    private JLabel fullListLabel;
    private JList fullList;
    final List<String> numbersList = new ArrayList<String>();
    private JButton submitBtn;
    private JButton closeBtn;
    private JPanel panel;

    private int arrayIndex = 0;// used for components adding into array

    public Surface(){
        panel = new JPanel();
        panel.setBackground(Color.WHITE);
        panel.setSize(300, 300);

        panel.setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.BOTH;


        topLabel = new JLabel("Enter your number and push submit");
        gbc.gridwidth = 3;
        gbc.gridx = 0; // column 
        gbc.gridy = 0; // row
        panel.add(topLabel, gbc);
        gbc.gridwidth = 1; // setting grid column with to default

        fullListLabel = new JLabel("Full list");
        gbc.gridx = 2;
        gbc.gridy = 1;
        panel.add(fullListLabel, gbc);          

        amountLabel = new JLabel("Amount");
        gbc.gridx = 0;
        gbc.gridy = 5;
        panel.add(amountLabel, gbc);

        amountAnswerFld = new JLabel("0");
        gbc.gridx = 1;
        gbc.gridy = 5;
        panel.add(amountAnswerFld, gbc);



        numberTxtFld = new JTextField();
        numberTxtFld.setColumns(10);
        gbc.gridx = 0;
        gbc.gridy = 1;
        panel.add(numberTxtFld, gbc);       

        submitBtn = new JButton("Submit");
        gbc.gridx = 1;
        gbc.gridy = 1;
        submitBtn.addActionListener(
                new ActionListener(){
                    @Override
                    public void actionPerformed(ActionEvent event) {

                        String text = numberTxtFld.getText();
                        numbersList.add(text);


                    }                   
                }
        );      
        panel.add(submitBtn, gbc);

        numbersList.add("first example");
        numbersList.add("second example");
        numbersList.add("third example");

        fullList = new JList(numbersList.toArray());
        fullList.setVisibleRowCount(6);
        fullList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        gbc.gridheight = 6;
        gbc.gridx = 2;
        gbc.gridy = 2;
        panel.add(new JScrollPane(fullList), gbc);
        gbc.gridheight = 1; // setting grid column with to default

        add(panel);


    }
}