newBirdListGUI

import javax.swing.*;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class BirdListGUI extends JFrame {

    private JPanel listPanel;
    private JPanel buttonPanel;
    private JTextArea birdList;
    private JLabel label;
    private JButton revButton;
    private JButton displayButton;
    private String stringList;
    private JCheckBox check;

    public BirdListGUI() {
        super("Bird List");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        // build panels
        buildListPanel();
        buildButtonPanel();

        // add panels
        add(listPanel, BorderLayout.WEST);
        add(buttonPanel, BorderLayout.SOUTH);
        pack();
        setVisible(true);
    }

    public void buildListPanel() {
        listPanel = new JPanel();
        label = new JLabel("Birds");

        birdList = new JTextArea(20, 30);
        birdList.setEditable(false);
        listPanel.add(label);
        listPanel.add(birdList);
    }

    public void buildButtonPanel() {
        buttonPanel = new JPanel();
        revButton = new JButton("Reverse Order");
        revButton.addActionListener(new ButtonListener());
        displayButton = new JButton("Display");
        displayButton.addActionListener(new DisplayListener());
        check = new JCheckBox("Remove birds");
        buttonPanel.add(check);
        buttonPanel.add(revButton);
        buttonPanel.add(displayButton);
    }

    public class DisplayListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            BirdList list = new BirdList();
            try {
                Scanner input1 = new Scanner(new File("birds1.txt")); //Populate complete bird list
                while (input1.hasNext())
                    list.insert(input1.nextLine());
            } catch (FileNotFoundException ex) { //Catch file not found exception
                System.out.println(ex.getMessage());
            }
            list.sort();
            String stringList = list.toString();
            birdList.setText(stringList);
            if (check.isSelected()) { //If selected, remove non-indigenous birds
                try {
                    Scanner input2 = new Scanner(new File("birds2.txt"));
                    while (input2.hasNext())
                        list.remove(input2.nextLine());
                } catch (FileNotFoundException ex) {
                    System.out.println(ex.getMessage());
                }
                list.sort();
                stringList = list.toString();
                birdList.setText(stringList);
            }
        }
    }

    public class ButtonListener implements ActionListener {
        boolean sorted = true;

        public void actionPerformed(ActionEvent e) {
            BirdList list = new BirdList();
            if (check.isSelected()) {
                try {
                    Scanner input1 = new Scanner(new File("birds1.txt"));
                    Scanner input2 = new Scanner(new File("birds2.txt"));
                    while (input1.hasNext())
                        list.insert(input1.nextLine());
                    while (input2.hasNext())
                        list.remove(input2.nextLine());
                } catch (FileNotFoundException ex) {
                    System.out.println(ex.getMessage());
                }
                String stringList = list.toString();
                birdList.setText(stringList);
            }
            if (!check.isSelected()) {
                try {
                    Scanner input1 = new Scanner(new File("birds1.txt"));
                    while (input1.hasNext())
                        list.insert(input1.nextLine());
                } catch (FileNotFoundException ex) {
                    System.out.println(ex.getMessage());
                }
                String stringList = list.toString();
                birdList.setText(stringList);
            }

            if (sorted) { //When Reverse button is pressed, list will alternate from sorted ascending and descending
                list.sortRev();
                stringList = list.toString();
                birdList.setText(stringList);
                sorted = false;
            } else if (!sorted) {
                list.sort();
                stringList = list.toString();
                birdList.setText(stringList);
                sorted = true;
            }
        }

    }

    public static void main(String[] args) {
        new BirdListGUI();
    }
}