I want to find the next (larger) prime number which will displayed on the label in GUI
But the code below is not okay.
Maybe the problem is d++, however I cannot think of other way to let the loop continue.
Can anyone help?
Thanks so much.
public class PrimeNumber extends JFrame implements ActionListener {
private JLabel label = new JLabel("2");
private JButton button = new JButton("Next Prime");
public PrimeNumber() {
FlowLayout layout = new FlowLayout();
this.setLayout(layout);
label = new JLabel("2");
button = new JButton("Next Prime");
this.add(label);
this.add(button);
button.addActionListener(this);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
}
#Override
public void actionPerformed(ActionEvent e) {
int d = 2;
do {
String t = String.valueOf(d);
label.setText(t);
d++;
}
while (d % 2 != 0);
}
}
public class TestPrimeNumber {
public static void main(String args[]) {
PrimeNumber frame = new PrimeNumber();
frame.setVisible(true);
}
}
I am working on a simple counter swing app. I'm trying to make it so when you click the check box, it will stay on the top and display a message dialog being "On Top" or "Not On Top".
However, when I click the checkbox after compiling and running, both of the messages display, and after clicking OK on both messages, the checkbox isn't even enabled. If I were to remove the showMessageDialog, it would still function properly, but I want to learn how to appropriately implement this.
Thank you in advance. Here is all of the code for the program:
public Class Counter {
JFrame frame;
JPanel panel;
JButton button, clear;
JTextField textC;
JLabel label;
JCheckBox cbox;
boolean topC = false;
int icount = 0;
String scount;
String topStatus = "";
public Counter() {
gui();
setActions();
}
public void gui() {
frame = new JFrame("Counter Program");
panel = new JPanel();
label = new JLabel("Counter");
textC = new JTextField();
textC.setPreferredSize(new Dimension(72,28));
textC.setEditable(false);
button = new JButton("Click");
clear = new JButton("Clear");
cbox = new JCheckBox("Top");
frame.setSize(350,80);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.add(panel);
panel.add(label);
panel.add(textC);
panel.add(button);
panel.add(clear);
panel.add(cbox);
frame.setVisible(true);
}
public void setActions() {
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
icount++;
scount = Integer.toString(icount);
textC.setText(scount);
}
});
clear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
icount = 0;
textC.setText("");
}
});
cbox.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent e) {
topC = !topC;
if (topC) {
topStatus = "Top";
}
else topStatus = "Not Top";
frame.setAlwaysOnTop(topC);
JOptionPane.showMessageDialog(frame, topStatus, "Top Setting", 1);
}
});
}
public static void main(String[]args) {
new Counter();
}
}
An ItemListener generates two events, one for the selection and one for the unselection (and vice versa). Read the section from the Swing tutorial on How to Write an ItemListener for more information and working exmaples if you really want to use an ItemListener.
Otherwise, use an ActionListener instead, it will only generate a single event.
I'm currently making our project and I'm having problem reseting JLabel back to "0". Here's the code
main code snippet (check note 1 for frame disposal method used):
import javax.swing.*; //import library
import java.awt.event.*;
import java.awt.*;
import java.util.*;
public class draft_main //class name
{
public static void main(String[] args)
{ //method name
JFrame f0 = new JFrame("POS"); //frame
JPanel p0 = new JPanel(); //panel inside the frame
JPanel p1 = new JPanel();
JPanel p2 = new JPanel();
JPanel p3 = new JPanel();
JPanel p4 = new JPanel();
JPanel p5 = new JPanel();
JPanel p6 = new JPanel();
JPanel p7 = new JPanel();
JLabel l0 = new JLabel("Amount:"); //label inside the panel
JLabel l1 = new JLabel("0");
JLabel l2 = new JLabel("Menu Code: ");
JLabel l3 = new JLabel("--Menu--");
JTextField tf0 = new JTextField("", 12); //user input for menu code
JButton b0 = new JButton("Checkout"); //buttons
JButton b1 = new JButton("Cancel");
JButton b2 = new JButton("Exit");
JButton b4 = new JButton("Accept");
JButton b7 = new JButton("Remove");
JOptionPane jop = new JOptionPane(); //JOptionPane
JTextField tf1 = new JTextField("1. Hot Pockets Pizza", 20); //list of menu
JTextField tf2 = new JTextField("2. Burger with Fries", 20);
JTextField tf3 = new JTextField("3. Sticky Rice (Bico)", 20);
ArrayList<String> ar = new ArrayList<String>(); //list of array
try{
b4.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) //what the accept button does
{
String order = tf0.getText(), tots="", temp="";
int o = Integer.parseInt(order);
int tot=0;
switch(o) //menu choice
{
case 1 : temp = l1.getText(); tot=Integer.parseInt(temp); tot=tot+250; tots = Integer.toString(tot); l1.setText(tots); ar.add("Hot Pockets Pizza"); break;
case 2 : temp = l1.getText(); tot=Integer.parseInt(temp); tot=tot+65; tots = Integer.toString(tot); l1.setText(tots); ar.add("Burger with Fries"); break;
case 3 : temp = l1.getText(); tot=Integer.parseInt(temp); tot=tot+12; tots = Integer.toString(tot); l1.setText(tots); ar.add("Sticky Rice (Bico)"); break;
default : jop.showMessageDialog(null, "Menu code not listed in menu", "Error", jop.INFORMATION_MESSAGE); break;
}
}
});
b0.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) //what the checkout button does
{
JFrame f1 = new JFrame("Checkout");
JFrame f2 = new JFrame("Order");
JPanel p8 = new JPanel();
JPanel p9 = new JPanel();
JPanel p10 = new JPanel();
JPanel p11 = new JPanel();
JPanel p12 = new JPanel();
JPanel p13 = new JPanel();
JPanel p14 = new JPanel();
JLabel l5 = new JLabel("Order list");
JLabel l6 = new JLabel(/*convert ArrayList to String then put here*/);
JLabel l4 = new JLabel("Cash");
JTextField tf4 = new JTextField("", 14);
JButton b5 = new JButton("Accept");
JButton b6 = new JButton("Cancel");
JButton b7 = new JButton("Ok");
b5.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
String cas = l1.getText(), in = tf4.getText();
int cash = Integer.parseInt(cas), inp = Integer.parseInt(in), cahs=0;
if(cash>inp)
{
jop.showMessageDialog(null, "Insufficient funds", "Lacking cash? Work for it.", jop.INFORMATION_MESSAGE);
}
else if(cash<inp)
{
cahs = inp - cash;
jop.showMessageDialog(null, "Change: " +cahs+". Thank you");
f1.dispatchEvent(new WindowEvent(f1, WindowEvent.WINDOW_CLOSING));
}
else if(cash==inp)
{
jop.showMessageDialog(null, "Thank you.", "Thank you.", jop.INFORMATION_MESSAGE);
f1.dispatchEvent(new WindowEvent(f1, WindowEvent.WINDOW_CLOSING));
}
}
});
b6.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
f1.dispatchEvent(new WindowEvent(f1, WindowEvent.WINDOW_CLOSING));
}
});
b7.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
f2.dispatchEvent(new WindowEvent(f2, WindowEvent.WINDOW_CLOSING));
}
});
p9.add(l0);
p9.add(l1);
p10.add(l4);
p10.add(tf4);
p11.add(b5);
p11.add(b6);
p12.add(l5);
p12.add(l6);
p13.add(b7);
p14.add(p12);
p14.add(p13);
p8.add(p10);
p8.add(p11);
p8.add(p9);
f1.add(p8);
f1.pack();
f1.setSize(240,170);
f1.setLocationRelativeTo(null);
f1.setResizable(false);
f1.setDefaultCloseOperation(f1.DISPOSE_ON_CLOSE);
f1.setVisible(true);
f2.add(p14);
f2.pack();
f2.setSize(270,100);
f2.setResizable(false);
f2.setLocationRelativeTo(null);
f2.setDefaultCloseOperation(f2.DISPOSE_ON_CLOSE);
f2.setVisible(true);
}
});
b1.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
l1.setText("0");
}
});
b2.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
f0.dispose();
}
});
}
catch(Exception e)
{
jop.showMessageDialog(null, "Error");
}
tf1.setEditable(false);
tf2.setEditable(false);
tf3.setEditable(false);
p4.add(tf1);
p5.add(tf2);
p6.add(tf3);
p7.add(l3);
p3.add(l2);
p3.add(tf0);
p3.add(b4);
p1.add(l0);
p1.add(l1);
p2.add(b0);
p2.add(b1);
p2.add(b2);
p0.add(p3);
p0.add(p1);
p0.add(p2);
p0.add(p7);
p0.add(p4);
p0.add(p5);
p0.add(p6);
f0.add(p0);
f0.pack();
f0.setSize(303,280);
f0.setLocationRelativeTo(null);
f0.setResizable(false);
f0.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f0.setVisible(true);
}
}
what happens is when the main window opens it asks for which from the menu did a guy order then it displays the price. During checkout the user will be asked to input amount of cash given and gives change if there's any. After then the checkout frame is then "properly" disposed (so as I think so), exposing the main frame. However the JLabel does not seem to update when I place another order or clear the current order and it bothers me since the main frame is supposed to be fully interactive until the main frame is closed.
note #1: I have used different methods on how to dispose the 2nd and 3rd frame which pops up since I thought it may have been because of the dispose(); does not really destroys the frame but let's it run in the background.
note #2: yes the program is not finished yet, but those don't matter for now for those will just be some minor features of the application.
You've several problems with this code, but the major ones that I see (and I haven't gone through all of it yet, so there may be more)
First and foremost, those JFrame sub-windows shouldn't be JFrames at all, but rather should be modal JDialogs. The reason for this is this gives you complete control over program flow when these dialogs are used, since you'll then know that the main program flow will be put on hold while the modal dialog is visible, and then the flow will resume as soon as the dialog is no longer visible. This way you can query the state of the dialog after it has been dealt with, and then use this information to update your GUI.
Your amount is shown in the l1 variable, and this will never change unless you specifically call setText(...) on this variable. You don't seem to be doing it when the order has been processed. Again modal dialogs will help you with this.
Your variable naming is bad. Instead of using meaningless letters and numbers for names, use names that make sense and that make your code self-commenting. So for instance, instead of l1, use amountLabel or something similar.
Your code is one huge god class with everything stuffed into the static main method, and this makes for a debugging nightmare. Java is an object-oriented language, and if used properly OOP techniques can help you reduce program complexity making your code easier for yourself and for us to understand. Start OOP-ifying your program and you'll see immediate dividends.
And I found your bug -- you're adding the l1 JLabel to another container, and so it is effectively being removed from the original JFrame. If you minimize your original GUI and then restore it, you'll see the amount l1 JLabel disappear.
Here's some sample code not yet done, but to give you an idea about adding OOP to the program:
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
#SuppressWarnings("serial")
public class Draft2 extends JPanel {
private List<MyItem> selectedItems = new ArrayList<>();
private NumberFormat formatter = NumberFormat.getCurrencyInstance();
private double total;
private JLabel totalAmountLabel = new JLabel(formatter.format(total));
private DefaultComboBoxModel<MyItem> comboModel = new DefaultComboBoxModel<>();
private JComboBox<MyItem> menuCombo = new JComboBox<>(comboModel);
public Draft2() {
// monospaced to make names and price line up
menuCombo.setFont(new Font(Font.MONOSPACED, Font.BOLD, 12));
// fill the JComboBox with items
comboModel.addElement(new MyItem("Baseball", 21.5));
comboModel.addElement(new MyItem("Bat", 50.8));
comboModel.addElement(new MyItem("Football", 22.26));
// create a JPanel to hold selection components and add components
JPanel selectionPanel = new JPanel();
selectionPanel.add(new JLabel("Menu:"));
selectionPanel.add(menuCombo);
selectionPanel.add(new JButton(new AcceptAction("Accept", KeyEvent.VK_A)));
// create a JPanel to hold the total amount information
JPanel totalAmountPanel = new JPanel();
totalAmountPanel.add(new JLabel("Total Amount:"));
totalAmountPanel.add(totalAmountLabel);
// create a JPanel to hold buttons, uses grid layout with a single row
JPanel btnPanel = new JPanel(new GridLayout(1, 0, 5, 0));
btnPanel.add(new JButton(new CheckOutAction("Check Out", KeyEvent.VK_C)));
btnPanel.add(new JButton(new CancelAction("Cancel", KeyEvent.VK_N)));
btnPanel.add(new JButton(new ExitAction("Exit", KeyEvent.VK_X)));
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
add(selectionPanel);
add(Box.createVerticalStrut(5)); // so don't crowd things
add(totalAmountPanel);
add(Box.createVerticalStrut(5));
add(btnPanel);
}
public void setTotalAmount(double total) {
totalAmountLabel.setText(formatter.format(total));
}
private class AcceptAction extends AbstractAction {
public AcceptAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
MyItem myMenuItem = (MyItem) menuCombo.getSelectedItem();
if (myMenuItem == null) {
return; // nothing selected, get out
}
selectedItems.add(myMenuItem);
double total = 0.0;
for (MyItem myItem : selectedItems) {
total += myItem.getCost();
}
setTotalAmount(total);
}
}
private class CheckOutAction extends AbstractAction {
public CheckOutAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Finish....
// open JDialog or JOptionPane
}
}
private class CancelAction extends AbstractAction {
public CancelAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Finish...
}
}
private class ExitAction extends AbstractAction {
public ExitAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("My GUI Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new Draft2());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
}
class MyItem {
private NumberFormat formatter = NumberFormat.getCurrencyInstance();
private String name;
private double cost;
public MyItem(String name, double cost) {
this.name = name;
this.cost = cost;
}
public String getName() {
return name;
}
public double getCost() {
return cost;
}
#Override
public String toString() {
return String.format("%-10s %s", name, formatter.format(cost));
}
}
I've tried to finish my program and all it does is it keeps on opening up a new JFrame. What have I done wrong?
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class BinaryConverter {
public static void main(String[] args) {
new BinaryConverter();
}
private JFrame frame;
private JButton button;
private JTextField text;
private JTextField text2;
private String decimalnumber = null;
// Constructor - builds and displays the window.
public BinaryConverter() {
frame = new JFrame("Let's Convert!");
// Create JLabel object for "Binary:" and add it to frame.
JLabel label = new JLabel("Binary:");
frame.setLayout(new FlowLayout());
frame.add(label);
// Create JTextField object and add it to frame
text = new JTextField(15);
frame.add(text);
// Create JLabel object for "Decimal:" and add it to frame.
JLabel label2 = new JLabel("Decimal:");
frame.add(label2);
// Create JTextField object and add it to frame
text2 = new JTextField(15);
frame.add(text2);
// Create JButton object and add it to frame.
button = new JButton("Convert");
button.addActionListener(new ButtonListener());
frame.add(button);
// Set frame attributes and make frame visible
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(250, 300);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public void Convert() {
String binary = text.getText(); // inserted binary number
int i;
for (i = 0; i < binary.length(); i++) { // The exponent
char select = binary.charAt(binary.length() - i);
char number = (char) (select * Math.pow(2, i));
decimalnumber += number;
}
}
public class ButtonListener implements ActionListener {
// This method is called automatically when button is clicked.
// Every Listener must have this method.
public void actionPerformed(ActionEvent e) {
BinaryConverter c = new BinaryConverter();
c.Convert();
if (button.getText().equals("Convert")) {
text2.setText(decimalnumber);
text.getText();
text2.getText();
} else {
}
}
}
}
This creates (and shows) a new instance of BinaryConverter!
// This method is called automatically when button is clicked.
// Every Listener must have this method.
public void actionPerformed(ActionEvent e) {
BinaryConverter c = new BinaryConverter(); //create/show a NEW instance!
c.Convert();
if (button.getText().equals("Convert")) {
text2.setText(decimalnumber);
text.getText();
text2.getText();
} else {
}
}
That is why it is showing new instances of the GUI.
So replace:
BinaryConverter c = new BinaryConverter();
c.Convert();
With simply:
Convert();
I am having problems understanding how to use an actionlistener to change the value of variables.
In my program I need to store the choices the user makes by selecting some radio buttons.
I have got a main class with a card layout, then several classes which each are different panels. In one of the panels I have some radio buttons, with an actionlistener as an inner class.
When I try to print the variable value in the main class, it is printed immediately, before the user has made a choice, as I instantiate the panel class and get the variable from it I get the variable before it has been changed by the user.
I know I should not think in a linear manner with Java, but how can I make sure that I fetch the variable after it has been changed by the user and not before? I will not be able to do that will I? I understand there is some flaw in my thinking but I haven't slept properly for ages and I just cannot get my head around this.
public class Screen3 extends JPanel{
JRadioButton addition = new JRadioButton("Addition");
JRadioButton subtraction = new JRadioButton("Subtraction");
JRadioButton multiplication = new JRadioButton("Multiplication");
JRadioButton division = new JRadioButton("Division");
JRadioButton all = new JRadioButton("All");
JRadioButton single = new JRadioButton("Single");
JRadioButton two = new JRadioButton("Double");
JRadioButton triple = new JRadioButton("Triple");
JRadioButton mix = new JRadioButton("Mix");
JRadioButton five = new JRadioButton("5");
JRadioButton ten = new JRadioButton("10");
private int type, digit, rounds;
public Screen3() {
JPanel firstButtonPanel = new JPanel();
JPanel secondButtonPanel = new JPanel();
ButtonGroup myFirstGroup = new ButtonGroup();
ButtonGroup mySecondGroup = new ButtonGroup();
myFirstGroup.add(addition);
myFirstGroup.add(subtraction);
myFirstGroup.add(multiplication);
myFirstGroup.add(division);
//myFirstGroup.add(all);
mySecondGroup.add(single);
mySecondGroup.add(two);
mySecondGroup.add(triple);
//mySecondGroup.add(mix);
firstButtonPanel.setLayout(new FlowLayout());
firstButtonPanel.add(addition);
firstButtonPanel.add(subtraction);
firstButtonPanel.add(multiplication);
firstButtonPanel.add(division);
//firstButtonPanel.add(all);
secondButtonPanel.setLayout(new FlowLayout());
secondButtonPanel.add(single);
secondButtonPanel.add(two);
secondButtonPanel.add(triple);
//secondButtonPanel.add(mix);
JPanel buttons = new JPanel();
buttons.setLayout(new BorderLayout());
buttons.add(selectionLabel, BorderLayout.NORTH);
buttons.add(firstButtonPanel, BorderLayout.CENTER);
buttons.add(secondButtonPanel, BorderLayout.SOUTH);
ButtonGroup myThirdGroup = new ButtonGroup();
JPanel endButtons = new JPanel();
myThirdGroup.add(five);
myThirdGroup.add(ten);
endButtons.add(five);
endButtons.add(ten);
endPanel.setLayout(new BorderLayout());
endPanel.add(rounds, BorderLayout.NORTH);
endPanel.add(endButtons, BorderLayout.CENTER);
setLayout(new BorderLayout());
add(buttons, BorderLayout.NORTH);
Selection sn = new Selection();
addition.addActionListener(sn);
subtraction.addActionListener(sn);
multiplication.addActionListener(sn);
division.addActionListener(sn);
single.addActionListener(sn);
two.addActionListener(sn);
triple.addActionListener(sn);
five.addActionListener(sn);
ten.addActionListener(sn);
}
public int getType() {
return type;
}
public int getDigit() {
return digit;
}
public int getRounds() {
return rounds;
}
public class Selection implements ActionListener {
public void actionPerformed(ActionEvent e) {
if(addition.isSelected()) {
type = 1;
}
else if(subtraction.isSelected()) {
type = 2;
}
else if(multiplication.isSelected())
type = 3;
else if(division.isSelected())
type = 4;
//else if(all.isSelected())
//type = 5;
if(single.isSelected()) {
digit = 1;
System.out.println("single");
}
else if(two.isSelected())
digit = 2;
else if(triple.isSelected())
digit = 3;
if(five.isSelected())
rounds = 5;
else if(ten.isSelected())
rounds = 10;
}
}
}
Here is the main class:
public class Driver {
public JFrame frame = new JFrame("Math Game");
public JPanel screens = new JPanel(new CardLayout());
int digit = 1;
int rounds = 1;
int type = 1;
Driver() {
}
public void show() {
JPanel buttonPanel = new JPanel();
JButton next = new JButton("Next");
JButton previous = new JButton("Previous");
buttonPanel.add(previous);
buttonPanel.add(next);
Screen1 screen1 = new Screen1();
Screen2 screen2 = new Screen2();
Screen3 screen3 = new Screen3();
screens.add(screen1, "welcome");
screens.add(screen2, "next");
screens.add(screen3, "selection");
frame.add(screens);
frame.add(buttonPanel, BorderLayout.PAGE_END);
frame.setSize(400, 500);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
next.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
CardLayout cl = (CardLayout)(screens.getLayout());
cl.next(screens);
}
});
previous.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
CardLayout cl = (CardLayout)(screens.getLayout());
cl.previous(screens);
}
});
}
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
Driver dr = new Driver();
dr.show();
}
});
}
}
I just try a test print of System.out.println(screen3.getType()); either in show() or main
Use JOptionPane/JDialog which has modality.
Have a read on How to Make Dialogs
In example here is only printed after JDialog is closed:
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JDialog jd = new JDialog();
jd.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
jd.setModal(true);
jd.pack();
jd.setVisible(true);
System.out.println("Here");
}
});
}
In this example here is only printed after JOptionPane is closed:
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JPanel panel=new JPanel();
panel.add(new JLabel("Hello, world!"));
JOptionPane.showMessageDialog(null, panel, "Panel Message",JOptionPane.PLAIN_MESSAGE);
System.out.println("Here");
}
});
}
I know I should not think in a linear manner with Java, but how can I
make sure that I fetch the variable after it has been changed by the
user and not before?
After using a modal JDialog/JOptionPane you would simply use public getters to access the variable contained within the class instance:
public class Test {
public static void main(String[] args) {
X x= new X();//will only return after dialog closed
System.out.println(x.getY());
}
}
class X {
private int y=0;//will be assigned during dialog/joptionpanes life span
public X() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
//creates and shows the modal dialog/optionpane which will allow modification of variable y through some input/controls
}
});
}
public int getY() {
return y;
}
}