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Java GUI Swing Passing Parameter From Another Class

Im bulding a GUI using eclipse plugin WindowsBuilder, im trying to pass a variable "comboBox kombo" from the initialize() method. I cant call the method to run my passed variable. The method supposed to get the data from my database to the comboBox.
Below i have attached my coding, any help will be appreciated ,Thank you!
import java.awt.EventQueue;
import javax.swing.JFrame;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.Color;
import java.awt.Label;
import java.awt.Font;
import javax.swing.JComboBox;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JMenuBar;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.swing.JTextField;
public class book extends JFrame {
Connection con = null;
PreparedStatement pst = null;
ResultSet rs = null;
private JFrame mdetail;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
book window = new book();
window.mdetail.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public book() {
initialize();
comboBox(kombo);
}
private void comboBox(JComboBox kombo) {
try
{
con= DriverManager.getConnection("jdbc:mysql://localhost/oop_project", "root","");
String sql = "select movieName from movie ";
pst = con.prepareStatement(sql);
rs = pst.executeQuery();
while(rs.next())
{
String name = rs.getString("movieName");
kombo.addItem(name);
}
}catch(Exception ex)
{
JOptionPane.showMessageDialog(null, ex);
}
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
mdetail = new JFrame();
mdetail.setTitle("Book Ticket");
mdetail.setBounds(100, 100, 450, 336);
mdetail.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mdetail.getContentPane().setLayout(null);
Label label = new Label("Movie Details");
label.setForeground(Color.BLACK);
label.setFont(new Font("Dialog", Font.PLAIN, 21));
label.setBounds(135, 10, 184, 54);
mdetail.getContentPane().add(label);
JComboBox kombo = new JComboBox();
kombo.setBounds(155, 70, 226, 22);
mdetail.getContentPane().add(kombo);
Label label_1 = new Label("Select Movie");
label_1.setBounds(74, 70, 75, 22);
mdetail.getContentPane().add(label_1);
Label label_1_1 = new Label("Select Date");
label_1_1.setBounds(74, 103, 75, 22);
mdetail.getContentPane().add(label_1_1);
JComboBox comboBox_1 = new JComboBox();
comboBox_1.setModel(new DefaultComboBoxModel(new String[] {"11-12-2022", "12-12-2022", "13-12-2022"}));
comboBox_1.setBounds(155, 103, 226, 22);
mdetail.getContentPane().add(comboBox_1);
Label label_1_1_1 = new Label("Select Time");
label_1_1_1.setBounds(74, 136, 75, 22);
mdetail.getContentPane().add(label_1_1_1);
JComboBox comboBox_1_1 = new JComboBox();
comboBox_1_1.setModel(new DefaultComboBoxModel(new String[] {"7.00am", "10.00am", "1.00pm", "5.00pm", "8.00pm"}));
comboBox_1_1.setBounds(155, 136, 226, 22);
mdetail.getContentPane().add(comboBox_1_1);
Label label_1_1_2 = new Label("Select Seat");
label_1_1_2.setBounds(74, 169, 75, 22);
mdetail.getContentPane().add(label_1_1_2);
JComboBox comboBox_1_2 = new JComboBox();
comboBox_1_2.setModel(new DefaultComboBoxModel(new String[] {"A(01)", "B(02)", "B(03)"}));
comboBox_1_2.setBounds(155, 169, 226, 22);
mdetail.getContentPane().add(comboBox_1_2);
JButton btnNewButton = new JButton("SUBMIT");
btnNewButton.setBounds(155, 241, 89, 23);
mdetail.getContentPane().add(btnNewButton);
JLabel lblNewLabel = new JLabel("View Seat Position");
lblNewLabel.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
seatposition.main(null);
mdetail.setVisible(false);
}
});
lblNewLabel.setBounds(282, 245, 112, 14);
mdetail.getContentPane().add(lblNewLabel);
Label label_1_2 = new Label("Welcome \"user\"");
label_1_2.setBounds(10, 10, 89, 22);
mdetail.getContentPane().add(label_1_2);
Label label_1_1_2_1_1 = new Label("Number of ticket");
label_1_1_2_1_1.setBounds(53, 202, 101, 22);
mdetail.getContentPane().add(label_1_1_2_1_1);
JComboBox comboBox_1_2_1 = new JComboBox();
comboBox_1_2_1.setBounds(155, 202, 226, 22);
mdetail.getContentPane().add(comboBox_1_2_1);
JMenuBar menuBar = new JMenuBar();
mdetail.setJMenuBar(menuBar);
JMenu mnNewMenu = new JMenu("Option");
menuBar.add(mnNewMenu);
JMenuItem mntmNewMenuItem = new JMenuItem("Logout");
mnNewMenu.add(mntmNewMenuItem);
JMenuItem exitmenu = new JMenuItem("Exit");
exitmenu.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int exit = JOptionPane.showConfirmDialog(null, "Are you sure you want to exit", "Exit", JOptionPane.YES_NO_OPTION);
if(exit==JOptionPane.YES_OPTION) {
System.exit(0);
}else {
mdetail.setVisible(true);
}
}
});
mnNewMenu.add(exitmenu);
}
}

How do you select CSV file to perform calculations on based on user input?

I'm currently making a user-input based program on Java Eclipse that is supposed perform calculations on data from a local csv file the user selects. The GUI code below is the source code that I have been using to make the GUI for the program. While I have managed to create the GUI, I am having trouble with "combining" the code listed under "CSVReader," which is a class I created, with the code for the GUI so that the user can select the CSV file. The user is supposed to select this CSV file by typing its path name into the text field box on the GUI.
Any help would be appreciated
GUI CODE
//GUI CODE
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.Color;
import javax.swing.JTextField;
public class Frame1 {
private JFrame frame;
private JTextField textField;
private JTextField txtCountryChosen;
/**
* #wbp.nonvisual location=71,14
*/
private final JTextField Program = new JTextField();
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Frame1 window = new Frame1();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Frame1() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
Program.setText("Statistics Manager");
Program.setColumns(10);
frame = new JFrame();
frame.getContentPane().setBackground(Color.LIGHT_GRAY);
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JButton btnNewButton = new JButton("Submit file path");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
String textFieldValue = textField.getText();
}
});
btnNewButton.setBounds(145, 48, 150, 25);
frame.getContentPane().add(btnNewButton);
textField = new JTextField();
textField.setBounds(116, 13, 200, 22);
frame.getContentPane().add(textField);
textField.setColumns(10);
JButton btnNewButton_1 = new JButton("Mean GDP");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
}
});
btnNewButton_1.setBounds(0, 154, 97, 25);
frame.getContentPane().add(btnNewButton_1);
JButton btnNewButton_2 = new JButton("Mean GDP_per_capita");
btnNewButton_2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
}
});
btnNewButton_2.setBounds(250, 154, 170, 25);
frame.getContentPane().add(btnNewButton_2);
JButton btnNewButton_3 = new JButton("Mean pop");
btnNewButton_3.setBounds(109, 154, 120, 25);
frame.getContentPane().add(btnNewButton_3);
txtCountryChosen = new JTextField();
txtCountryChosen.setBounds(42, 104, 116, 22);
frame.getContentPane().add(txtCountryChosen);
txtCountryChosen.setColumns(10);
JButton btnNewButton_4 = new JButton("Select country");
btnNewButton_4.setBounds(270, 103, 150, 25);
frame.getContentPane().add(btnNewButton_4);
JButton btnNewButton_5 = new JButton("Print Results in Txt File");
btnNewButton_5.setBounds(131, 201, 200, 20);
frame.getContentPane().add(btnNewButton_5);
}
}
CSVReader
//CSVREADER
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintStream;
import java.util.Scanner;
public class CSVReader {
public static void main(String[] args) {
Scanner scan= new Scanner(System.in);
System.out.println("Enter file path name");
String file_path_name = scan.nextLine();
System.out.println(file_path_name);
String path= file_path_name;
String line = "";
try {
BufferedReader br = new BufferedReader(new FileReader(path));
while((line = br.readLine()) !=null){
String[] values = line.split(",");
System.out.println("Country: " + values[0] + ", Year: " + values[2] + ", GDP: " + values[6] + ", GDP_per_capita: " + values[12] + ", Population: " + values[10]);
/*PrintStream myconsole= new PrintStream(new File("E://java.txt"));
System.setOut(myconsole);
myconsole.print(path);*/
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}

is the method to create simple login wrong

I am a newbie in Java GUI development and I am stuck in the following code.
I am open to suggestions. I am actually trying to create a simple login that gives OK if the password is matched to the number 3124, and otherwise shows the error message. Please help me.
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JTextField;
public class testing {
private JFrame frame;
private JTextField username;
private JTextField password;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
testing window = new testing();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public testing() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JButton btnNewButton_1 = new JButton("cancel");
btnNewButton_1.setBounds(266, 181, 109, 56);
frame.getContentPane().add(btnNewButton_1);
username = new JTextField();
username.setBounds(227, 11, 128, 39);
frame.getContentPane().add(username);
username.setColumns(10);
password = new JTextField();
password.setBounds(227, 76, 128, 39);
frame.getContentPane().add(password);
final int num;
num=Integer.parseInt(password);
password.setColumns(10);
JButton btnNewButton = new JButton("login");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(num==3124)
{JOptionPane.showMessageDialog(null, "correct");}
else
{JOptionPane.showMessageDialog(null, "wrong");}
}
});
btnNewButton.setBounds(62, 181, 123, 56);
frame.getContentPane().add(btnNewButton);
}
}

You were checking the password even before the user has had the chance to enter anything into the text box. You need to get and check the value of num in the event listener code i.e. in actionPerformed. Also, don't convert the password to int (someone may enter some non-numeric string).
This code below works better.
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import javax.swing.JTextField;
public class Testing {
private JFrame frame;
private JTextField username;
private JTextField password;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Testing window = new Testing();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Testing() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JButton btnNewButton_1 = new JButton("cancel");
btnNewButton_1.setBounds(266, 181, 109, 56);
frame.getContentPane().add(btnNewButton_1);
username = new JTextField();
username.setBounds(227, 11, 128, 39);
frame.getContentPane().add(username);
username.setColumns(10);
password = new JTextField();
password.setBounds(227, 76, 128, 39);
frame.getContentPane().add(password);
password.setColumns(10);
JButton btnNewButton = new JButton("login");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
final String num;
num = (password.getText());
if (num.equalsIgnoreCase("3124")) {
JOptionPane.showMessageDialog(null, "correct");
} else {
JOptionPane.showMessageDialog(null, "wrong");
}
}
});
btnNewButton.setBounds(62, 181, 123, 56);
frame.getContentPane().add(btnNewButton);
}
}

How can activate another gui class with JButton

I have two GUI classes named Menu and convert. I want to run the convert class when I click the "open" button. It looks so simple, but I couldn't figure it out.
Menu class
package com.ui;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class Menu {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Menu window = new Menu();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Menu() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton btnConvert = new JButton("open");
btnConvert.setBounds(44, 52, 89, 23);
btnConvert.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
//???
}
});
frame.getContentPane().setLayout(null);
frame.getContentPane().add(btnConvert);
}
}
convert class
package com.ui;
import java.awt.EventQueue;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.border.TitledBorder;
import java.awt.Color;
import javax.swing.JComboBox;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class convert {
private JFrame frmTitle;
private JTextField textField;
private double value;
private ButtonGroup group;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
convert window = new convert();
window.frmTitle.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public convert() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frmTitle = new JFrame();
frmTitle.setTitle("TITLE");
frmTitle.setBounds(100, 100, 450, 300);
frmTitle.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmTitle.getContentPane().setLayout(null);
JLabel lblInputValue = new JLabel("Input value:");
lblInputValue.setBounds(29, 22, 79, 14);
frmTitle.getContentPane().add(lblInputValue);
textField = new JTextField();
textField.setBounds(22, 47, 86, 20);
frmTitle.getContentPane().add(textField);
textField.setColumns(10);
JPanel panel = new JPanel();
panel.setBorder(new TitledBorder(null, "Convert", TitledBorder.LEADING, TitledBorder.TOP, null, Color.RED));
panel.setBounds(29, 118, 264, 133);
frmTitle.getContentPane().add(panel);
panel.setLayout(null);
final JRadioButton rdbtnKelvin = new JRadioButton("Kelvin");
rdbtnKelvin.setBounds(6, 30, 67, 23);
panel.add(rdbtnKelvin);
final JRadioButton rdbtnFahrenheit = new JRadioButton("Fahrenheit");
rdbtnFahrenheit.setBounds(71, 30, 77, 23);
panel.add(rdbtnFahrenheit);
final JRadioButton rdbtnCelcius = new JRadioButton("Celcius");
rdbtnCelcius.setBounds(174, 30, 67, 23);
panel.add(rdbtnCelcius);
group = new ButtonGroup();
group.add(rdbtnCelcius);
group.add(rdbtnFahrenheit);
group.add(rdbtnKelvin);
final JComboBox comboBox = new JComboBox();
comboBox.setModel(new DefaultComboBoxModel(new String[] {"Celcius", "Fahrenheit", "Kelvin"}));
comboBox.setBounds(177, 47, 116, 20);
frmTitle.getContentPane().add(comboBox);
JButton btnConvert = new JButton("CONVERT");
btnConvert.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
value = Double.parseDouble(textField.getText().toString());
if(comboBox.getSelectedItem().toString().equals("Celcius")){
if(rdbtnCelcius.isSelected()==true){
value = value;
}
else if (rdbtnFahrenheit.isSelected()==true){
value= 1.8*value +32;
}
else{
value =value+273;
}
}
else if (comboBox.getSelectedItem().toString().equals("Fahrenheit")){
if(rdbtnFahrenheit.isSelected()==true){
value = value;
}
else if (rdbtnCelcius.isSelected()==true){
value= (value-32)*1.8;
}
else{
value =(value-32)/1.8+273;
}
}
else{
if(rdbtnCelcius.isSelected()==true){
value = value-273;
}
else if (rdbtnFahrenheit.isSelected()==true){
value= value -273*1.8+32;
}
else{
value =value;
}
}
textField.setText(value +"");
textField.setEnabled(false);
}
});
btnConvert.setBounds(303, 114, 89, 23);
frmTitle.getContentPane().add(btnConvert);
JButton btnClear = new JButton("CLEAR");
btnClear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
textField.setText("");
textField.setEnabled(true);
comboBox.setSelectedIndex(0);
rdbtnKelvin.setSelected(true);
}
});
btnClear.setBounds(303, 170, 89, 23);
frmTitle.getContentPane().add(btnClear);
}
}

First of all, class names and constructors should start with an upper case letter, like you did it for class Menu, but not for class convert.
A Java programm should have just one and only one main method for all classes. So, delete complete your main method from Convert class, put new Convert(); in the actionPerformed() method of btnConvert in Menu class:
btnConvert.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
new Convert();
}
});
and add frmTitle.setVisible(true); to the end of the initialize() method of Convert class.

First, your class names should begin with a capital letter, so instead of "convert" it should be "Convert.
Create a public method in Convert:
public JFrame getFrame() {
return frmTitle;
}
Then in your button's actionPerformed() method, just:
Convert w = new Convert();
w.getFrame().setVisible(true);

Rename file/directory using JFileChooser() and JButton()

I'm trying to rename file or directory using JFileChooser() and JButton(). But it gives me a "NullPointer exeption" in line 81 where I have
action listener
// button action
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String newFileName = textField.getText();
// exeption is here!!!
File oldFile = new File(fileChooser.getSelectedFile(), null);
File newFileOrDirectoryName = new File(newFileName);
if (oldFile.renameTo(newFileOrDirectoryName)) {
System.out.println("renamed");
} else {
System.out.println("Error");
}
}
});
I have to select some file or directory from my FileChooser(), then write new name for file or directory in TextField() and then push the Button() to rename it.Can you say where I go wrong and how to solve this problem.
This is a full code:
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JFileChooser;
public class App {
private JFrame frame;
private JTextField textField;
private JFileChooser fileChooser;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
App window = new App();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public App() {
initialize();
}
public void initialize() {
frame = new JFrame();
frame.getContentPane().setFont(new Font("Tahoma", Font.BOLD, 14));
frame.setBounds(100, 100, 539, 469);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
frame.getContentPane().setBackground(new Color(255, 246, 143));
JLabel label = new JLabel("Rename file or package");
label.setFont(new Font("Tahoma", Font.BOLD, 14));
label.setHorizontalAlignment(SwingConstants.LEFT);
label.setBounds(10, 0, 302, 32);
frame.getContentPane().add(label);
JLabel label_1 = new JLabel("New file/package name");
label_1.setHorizontalAlignment(SwingConstants.LEFT);
label_1.setFont(new Font("Tahoma", Font.BOLD, 14));
label_1.setBounds(10, 358, 194, 25);
frame.getContentPane().add(label_1);
textField = new JTextField();
textField.setBounds(10, 387, 179, 32);
frame.getContentPane().add(textField);
textField.setColumns(10);
JButton button = new JButton("Rename");
button.setFont(new Font("Tahoma", Font.BOLD, 14));
button.setBounds(199, 384, 151, 34);
button.addActionListener(null);
frame.getContentPane().add(button);
fileChooser = new JFileChooser();
fileChooser.setBounds(10, 51, 505, 289);
frame.getContentPane().add(fileChooser);
// button action
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String newFileName = textField.getText();
File oldFile = new File(fileChooser.getSelectedFile(), null);
File newFileOrDirectoryName = new File(newFileName);
if (oldFile.renameTo(newFileOrDirectoryName)) {
System.out.println("renamed");
} else {
System.out.println("Error");
}
}
});
}
}

It's because you're passing null to the File constructor at line 81, which give a NullPointerException when passed null. This can be read in the documentation here.
I think the solution is to remove the 'new File' part and replace it by:
File oldFile = fileChooser.getSelectedFile();
The bug was actually quite easy to see by pasting the code into IntelliJ: