errors because of int conversion placement

Question

i have narrowed it down so that the int conversion from jtextfield to int is the errors but am unsure where to put them

   package demooo;

/*
 * GridBagLayoutDemo.java requires no other files.
 */
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;
import javax.swing.text.DefaultCaret;

public class Demooo implements ActionListener {

    final static boolean shouldFill = true;
    final static boolean shouldWeightX = true;
    final static boolean RIGHT_TO_LEFT = false;
    private final static String newline = "\n";
    protected JTextField textField;
    protected JTextArea textArea;

    public static void addComponentsToPane(Container pane) {

        if (RIGHT_TO_LEFT) {

pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
        }

        /*test for team names */
        //String[] teamString = {};
        String[] reffString = {"bob", "fred", "jon", "ed", "killa"};
         JLabel label;
        JLabel labelA;
        JLabel labelH;
        JLabel labelA2;
        JLabel labelH2;
        JTextField text;
        int g = 0 ;
        JButton next;
        JButton button1;
        JButton button2;
        JLabel blank;
        JLabel Head;
        JComboBox comboH;
        JComboBox comboA;
        JComboBox comboReff;
        String winner;
        Connection con = null;
        Statement st = null;
        ResultSet rs = null;
       /* int h = Integer.parseInt(homegoal.getText());
        int a = Integer.parseInt(awaygoal.getText());
        int h2 = Integer.parseInt(homegoal2.getText());
        int a2 = Integer.parseInt(awaygoal2.getText());*/

        pane.setLayout(new GridBagLayout());

        GridBagConstraints c = new GridBagConstraints();
        if (shouldFill) {
            //natural height, maximum width
            c.fill = GridBagConstraints.HORIZONTAL;
        }
        /*select home team*/

        labelH = new JLabel("Home Team");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 0;
        c.gridy = 0;
        pane.add(labelH, c);

        comboH = new JComboBox(/*teamString*/);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.weightx = 1;
        c.gridx = 0;
        c.gridy = 1;
        pane.add(comboH, c);
        /* to add blank space between teams*/

 /*cant get right yet but will try */
 /*select away team*/
        labelA = new JLabel("Away Team");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 7;
        c.gridy = 0;
        pane.add(labelA, c);

        comboA = new JComboBox(/*teamString*/);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.weightx = 1;
        c.gridx = 7;
        c.gridy = 1;
        pane.add(comboA, c);

        /*Team 1 home*/
        Head = new JLabel("Home Game Score", SwingConstants.CENTER);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.ipady = 20;      //make this component tall
        c.weightx = 0.0;
        c.gridwidth = 3;
        c.gridx = 0;
        c.gridy = 3;
        pane.add(Head, c);
        Head.setFont(new Font("Serif", Font.BOLD, 18));

        /*enter score for home game*/
        labelH2 = new JLabel("Home Team Goals");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 0;
        c.gridy = 4;
        pane.add(labelH2, c);

        JTextField homegoal = new JTextField(2);
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 0;
        c.gridy = 5;
        pane.add(homegoal, c);
int h = Integer.parseInt(homegoal.getText());
        /*ref section*/
        label = new JLabel("Referee");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 3;
        c.gridy = 4;
        pane.add(label, c);

        comboReff = new JComboBox(reffString);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.weightx = 1;
        c.gridx = 3;
        c.gridy = 5;
        pane.add(comboReff, c);

        /*other teams goals*/
        label = new JLabel("Away Team Goals");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 7;
        c.gridy = 4;
        pane.add(label, c);

        JTextField awaygoal = new JTextField(2);
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 7;
        c.gridy = 5;
        pane.add(awaygoal, c);
        int a = Integer.parseInt(awaygoal.getText());


        /*team 2 is home team*/
        Head = new JLabel("Away Game Score", SwingConstants.CENTER);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.ipady = 20;      //make this component tall
        c.weightx = 0.0;
        c.gridwidth = 3;
        c.gridx = 0;
        c.gridy = 6;
        pane.add(Head, c);
        Head.setFont(new Font("Serif", Font.BOLD, 18));

        label = new JLabel("Home Team Goals");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 0;
        c.gridy = 8;
        pane.add(label, c);

        JTextField homegoal2 = new JTextField(2);
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 0;
        c.gridy = 9;
        pane.add(homegoal2, c);
        int h2 = Integer.parseInt(homegoal2.getText());
        /*reff */
        label = new JLabel("Referee");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 3;
        c.gridy = 8;
        pane.add(label, c);

        comboReff = new JComboBox(reffString);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.weightx = 1;
        c.gridx = 3;
        c.gridy = 9;
        pane.add(comboReff, c);


        /*next teams goals*/
        label = new JLabel("Away Team Goals");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 7;
        c.gridy = 8;
        pane.add(label, c);

        JTextField awaygoal2 = new JTextField(2);
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 7;
        c.gridy = 9;
        pane.add(awaygoal2, c);

        int a2 = Integer.parseInt(awaygoal2.getText());


        /*match set complete*/
         button1 = new JButton("The winner of this set of matches was");
        c.fill = GridBagConstraints.HORIZONTAL;
        c.ipady = 20;      //make this component tall
        c.weightx = 2;
        c.gridwidth = 8;
        c.gridx = 0;
        c.gridy = 10;
        pane.add(button1, c);
        button1.addActionListener(new ActionListener() {

                        public void actionPerformed(int g) {
                        if (h>a){
                        g =+1;
                        }else if (a>h){
                        g =-1;}
                        else{
                        g = g;}
                        }

            @Override
            public void actionPerformed(ActionEvent ae) {
                throw new UnsupportedOperationException("Not supported 
yet."); //To change body of generated methods, choose Tools | Templates.
            }
        });

        if (g > 0){
        winner = "home";
        }
        else if (g < 0){
        winner = "away";}
        else {
        winner = "Draw";}

        label = new JLabel (winner);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.ipady = 20;      //make this component tall
        c.weightx = 2;
        c.gridwidth = 8;
        c.gridx = 0;
        c.gridy = 11;
        pane.add(label, c);

        button2 = new JButton ("Next Match");
        c.fill = GridBagConstraints.HORIZONTAL;
        c.ipady = 20;      //make this component tall
        c.weightx = 2;
        c.gridwidth = 8;
        c.gridx = 0;
        c.gridy = 12;
        pane.add(button2, c);

        try {
            con = DriverManager.getConnection("jdbc:derby://localhost:1527/" 
+ "jfl", "jfl", "jfl");
            st = con.createStatement();
            String s = "SELECT Teamname,ID from JFL.TEAMS";

            rs = st.executeQuery(s);
            while (rs.next()) {
                comboH.addItem(rs.getString(1) + "  " + rs.getString(2));
                comboA.addItem(rs.getString(1) + "  " + rs.getString(2));
            }
        } catch (Exception e) {
            JOptionPane.showMessageDialog(null, "ERROR");
        } finally {
            try {
                st.close();
                rs.close();
                con.close();
            } catch (Exception e) {
                JOptionPane.showMessageDialog(null, "ERROR CLOSE");
            }
        }
    }

    /**
     * Create the GUI and show it.
     *
     * @param evt
     */
    public void actionPerformedd(ActionEvent evt) {

        String text = textField.getText();
        textArea.append(text + newline);
        textField.selectAll();

        //Make sure the new text is visible, even if there
        //was a selection in the text area.
        textArea.setCaretPosition(textArea.getDocument().getLength());
    }

    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("Junior Football League");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JMenuBar menubar = new JMenuBar();
        frame.setJMenuBar(menubar);

        //file menu
        JMenu fileMenu = new JMenu("File");
        menubar.add(fileMenu);

        JMenuItem quitItem = new JMenuItem("Quit");
        fileMenu.add(quitItem);
        quitItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                //call another method to close window
                System.exit(0);
            }
        });
        JMenu helpItem = new JMenu("Teams");
        menubar.add(helpItem);

        JMenuItem subMenu = new JMenuItem("Create New Team");


    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }

}

the error message given is

run:

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.lang.Integer.parseInt(Integer.java:592) at java.lang.Integer.parseInt(Integer.java:615) at demooo.Demooo.addComponentsToPane(Demooo.java:127) at demooo.Demooo.createAndShowGUI(Demooo.java:918) at demooo.Demooo.access$000(Demooo.java:12) at demooo.Demooo$6.run(Demooo.java:936) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756) at java.awt.EventQueue.access$500(EventQueue.java:97) at java.awt.EventQueue$3.run(EventQueue.java:709) at java.awt.EventQueue$3.run(EventQueue.java:703) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80) at java.awt.EventQueue.dispatchEvent(EventQueue.java:726) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) at java.awt.EventDispatchThread.run(EventDispatchThread.java:82) BUILD SUCCESSFUL (total time: 1 second)

You say you narrowed it down, but that looks like you just dumped your entire code in here. Please create a proper minimal reproducible example or at least reduce it to only the code where the error occurs, this is way too much — UnholySheep
You can't parse the integer if there's nothing to parse... Looks like you need to check if the String is empty before attempting to parse it (based off the error message). — DigitalNinja
c.gridx = 0; so nothing to to with anything, just a placement for a label — Zelda Tiason

clinomaniac clinomaniac · Accepted Answer · 2017-12-18T22:37:27

You have this at line 127.

int h = Integer.parseInt(homegoal.getText());

The following lines from the exception tell me that the error is at that line and it is regarding conversion form String to Int.

java.lang.Integer.parseInt(Integer.java:592) at 
java.lang.Integer.parseInt(Integer.java:615) at 
demooo.Demooo.addComponentsToPane(Demooo.java:127) at

I would take a look at what value is coming through for homegoal.getText(). If it is null then put 0 in the int variable.

Edit: From the looks of it, you are just creating the text field so it will be empty. That's why the error. Check to see if empty and assign 0 on empty.

int h = (homegoal == null || homegoal.getText().isEmpty()? 0:Integer.parseInt(homegoal.getText());

errors because of int conversion placement

1 Answers