Flowlayout question

Question

hi everyone...i have a panel that have a flow layout and a scroll pane attached to it and i also have a button that when pressed, a component is added to the panel...my problem is that when i press the button, the components are added fine but when there is no more place on the line, the components are not placed on the second line even though i have a scroll pane and a flow layout....
please help
here are the three classes needed to show the problem
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.IOException;
public class GUI extends JFrame implements ActionListener {
    public GUI() {
        initializeGUI();
    public void initializeGUI() {
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setResizable(true);
        setTitle("DVD");
        setSize(1000, 700);
        setLocation(20, 20);
        JTabbedPane tp = new JTabbedPane(JTabbedPane.LEFT);
        getContentPane().add(tp);
        tp.addTab("Rent Page", new MultipleRentGUI());
    public static void main(String[] args) {
        new GUI().setVisible(true);
     * Invoked when an action occurs.
    public void actionPerformed(ActionEvent e) {
    ActionListener BackupListener = new ActionListener() {
import javax.swing.*;
import javax.swing.border.Border;
import javax.swing.border.TitledBorder;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.GregorianCalendar;
public class MultipleRentGUI extends JPanel implements ActionListener, GUIConstants {
    private JRadioButton id = new JRadioButton("Customer ID", true);
    private JRadioButton name = new JRadioButton("Customer name");
    private JLabel label = new JLabel("Customer ID: ");
    private JTextField cust = new JTextField(10);
    private JButton rent = new JButton("Rent");
    private JButton reset = new JButton("Reset");
    private JButton add = new JButton("Add");
    private JButton remove = new JButton("Remove");
    private JPanel bPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
    private JPanel lPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
    private JPanel b2Panel = new JPanel(new FlowLayout(FlowLayout.LEFT));
    private JPanel tPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
    private JPanel b3Panel = new JPanel(new FlowLayout(FlowLayout.LEFT));
    private JPanel nPanel = new JPanel();
    private ArrayList<MultipleTitleRentGUI> titles = new ArrayList<MultipleTitleRentGUI>();
    private int count = 0;
    private Calendar c = Calendar.getInstance();
    private final int FONT_SIZE = 15;
    private Font f = new Font("Times New Roman", Font.BOLD, FONT_SIZE);
    private Font borderFont = new Font("Times New Roman", Font.BOLD, FONT_SIZE + 5);
    public MultipleRentGUI() {
        setupComponents();
        setupFonts();
        setupButtons();
        initializeGUI();
    public void setupFonts() {
        id.setFont(f);
        name.setFont(f);
        rent.setFont(f);
        reset.setFont(f);
        cust.setFont(f);
    public void setupComponents() {
        Border b = BorderFactory.createLoweredBevelBorder();
        this.setBorder(BorderFactory.createTitledBorder(b
                , "Multiple Rent Page"
                , TitledBorder.DEFAULT_JUSTIFICATION
                , TitledBorder.DEFAULT_POSITION
                , borderFont
                , Color.blue));
        cust.setBorder(BorderFactory.createLoweredBevelBorder());
        nPanel.setLayout(new BoxLayout(nPanel, BoxLayout.Y_AXIS));
    public void initializeGUI() {
        rent.setEnabled(true);
        reset.setEnabled(false);
        ButtonGroup bg = new ButtonGroup();
        bg.add(id);
        bg.add(name);
        setLayout(new BorderLayout());
        add(nPanel, BorderLayout.NORTH);
        bPanel.add(id);
        bPanel.add(name);
        nPanel.add(bPanel);
        lPanel.add(label);
        lPanel.add(cust);
        nPanel.add(lPanel);
        b2Panel.add(add);
        b2Panel.add(remove);
        nPanel.add(b2Panel);
        JScrollPane sp = new JScrollPane(tPanel
                , JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED
                , JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
        add(sp, BorderLayout.CENTER);
        b3Panel.add(rent);
        b3Panel.add(reset);
        add(b3Panel, BorderLayout.SOUTH);
    public void setupButtons() {
        rent.addActionListener(this);
        rent.setActionCommand("rent");
        reset.addActionListener(this);
        reset.setActionCommand("reset");
        id.addActionListener(this);
        id.setActionCommand("id");
        name.addActionListener(this);
        name.setActionCommand("name");
        add.addActionListener(this);
        add.setActionCommand("add");
        remove.addActionListener(this);
        remove.setActionCommand("remove");
    public void resetFields() {
        rent.setEnabled(true);
        reset.setEnabled(false);
        id.setSelected(true);
        cust.setText("");
        label.setText("Customer ID: ");
    public Box addComponent(Component c1, Component c2, int spacing) {
        return null;
     * Invoked when an action occurs.
    public void actionPerformed(ActionEvent e) {
        if (e.getActionCommand().equalsIgnoreCase("id")) {
            label.setText("Customer ID: ");
        if (e.getActionCommand().equalsIgnoreCase("name")) {
            label.setText("Customer Name: ");
        if (e.getActionCommand().equalsIgnoreCase("reset")) {
            resetFields();
        if (e.getActionCommand().equalsIgnoreCase("add")) {
            titles.add(new MultipleTitleRentGUI());
            tPanel.add(titles.get(count));
            count++;
            revalidate();
        if (e.getActionCommand().equalsIgnoreCase("remove")) {
            if (count == 0) {
                return;
            } else {
                tPanel.remove(titles.get(count - 1));
                titles.remove(count - 1);
                count--;
                tPanel.revalidate();
                tPanel.repaint();
        if (e.getActionCommand().equalsIgnoreCase("rent")) {
import javax.swing.*;
import javax.swing.border.Border;
import javax.swing.border.TitledBorder;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
public class MultipleTitleRentGUI extends JPanel implements ActionListener {
    private JLabel title = new JLabel("Title Barcode: ");
    private JTextField barcode = new JTextField(5);
    private JRadioButton reg = new JRadioButton("Regular price", true);
    private JRadioButton half = new JRadioButton("Half price");
    private JRadioButton free = new JRadioButton("Free of Charge");
    private int fee = getRentFee();
    private JPanel text = new JPanel(new FlowLayout(FlowLayout.LEFT));
    private JPanel buttons = new JPanel();
    private final int FONT_SIZE = 15;
    private Font f = new Font("Times New Roman", Font.BOLD, FONT_SIZE);
    private Font borderFont = new Font("Times New Roman", Font.BOLD, FONT_SIZE + 5);
    public MultipleTitleRentGUI() {
        setupButtons();
        setupComponents();
        initializeGUI();
    private void initializeGUI() {
        setLayout(new BorderLayout());
        setSize(50, 60);
        ButtonGroup bg = new ButtonGroup();
        bg.add(reg);
        bg.add(half);
        bg.add(free);
        text.add(title);
        text.add(barcode);
        add(text, BorderLayout.NORTH);
        buttons.add(reg);
        buttons.add(half);
        buttons.add(free);
        add(buttons, BorderLayout.CENTER);
    private void setupButtons() {
        reg.setFont(f);
        half.setFont(f);
        free.setFont(f);
        reg.addActionListener(this);
        reg.setActionCommand("regular");
        half.addActionListener(this);
        half.setActionCommand("half");
        free.addActionListener(this);
        free.setActionCommand("free");
    private void setupComponents() {
        Border b = BorderFactory.createLoweredBevelBorder();
        this.setBorder(BorderFactory.createTitledBorder(b
                , "Title"
                , TitledBorder.DEFAULT_JUSTIFICATION
                , TitledBorder.DEFAULT_POSITION
                , borderFont
                , Color.blue));
        barcode.setBorder(BorderFactory.createLoweredBevelBorder());
        buttons.setLayout(new BoxLayout(buttons, BoxLayout.Y_AXIS));
    public String getBarcode() {
        return barcode.getText();
    public int getFee() {
        return fee;
    private int getRentFee() {
        int cost = 0;
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            Connection con = DriverManager.getConnection("jdbc:mysql://localhost/dvd", "root", "swordfrogy");
            String sql = "SELECT rent " +
                    "FROM fees";
            Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                cost = rs.getInt("rent");
        } catch (InstantiationException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        } catch (IllegalAccessException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        } catch (ClassNotFoundException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        } catch (SQLException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        return cost;
     * Invoked when an action occurs.
    public void actionPerformed(ActionEvent e) {
        if (e.getActionCommand().equalsIgnoreCase("regular")) {
            fee = getRentFee();
        if (e.getActionCommand().equalsIgnoreCase("half")) {
            fee = getRentFee() / 2;
        if (e.getActionCommand().equalsIgnoreCase("free")) {
            fee = 0;
}

Answer 1

Sorry, I've just read the question more carefully :)
FlowLayout will add the component on a second line if it runs out of space on the first. That's not the cause of the problem.
However, this container is in a scroll pane. That means it will never run out of space. The layout manager is still adding components to the first line - it's just that they can't be seen because you've suppressed the horizontal scroll bar.
Note that suppressing the scroll bar does just that: it doesn't restrict the size of the component in the viewport.
If you want to check that that's what happening, add a println() after your revalidate() call to dump the preferred size of the container - you should see it growing horizontally.
In order to make the components flow as you intend, the solution I use is an extension of JViewport which uses its own custom layout manaer.
There may be an easier solution but I didn't find one before I wrote that and I've stuck with it ever since.