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Blank screen integrating JavaFX Scene in Swing using Netbeans

I am not able to understand where my code is wrong. I tried to integrate several example, but the result is that nothing is displayed. In pure JavaFX environment, everything is correct; but in mixed mode, no. The goal is to use the NetBeans designer and integrate existing code with the new one without losing NetBeans facility.
public class VisualizzaFattureXML extends javax.swing.JFrame {
private final JFXPanel fxPanel;
/**
* Creates new form VisualizzaFattureXML
*/
public VisualizzaFattureXML() {
fxPanel = new JFXPanel();
initComponents();
}
private void initFX(JFXPanel fxPanel) {
// This method is invoked on the JavaFX thread
Scene scene = createScene();
fxPanel.setScene(scene);
}
private Scene createScene() {
Group root = new Group();
Scene scene = new Scene(root, Color.ALICEBLUE);
Text text = new Text();
text.setX(40);
text.setY(100);
text.setFont(new Font(25));
text.setText("Welcome JavaFX!");
root.getChildren().add(text);
return (scene);
}
#Override
public void setVisible(boolean t) {
super.setVisible(t);
Platform.runLater(new Runnable() {
#Override
public void run() {
initFX(fxPanel);
}
});
jScrollPane1.add(fxPanel);
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
jButton1 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jScrollPane1.setToolTipText("");
jButton1.setText("jButton1");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addComponent(jButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 660, Short.MAX_VALUE)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 449, javax.swing.GroupLayout.PREFERRED_SIZE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jScrollPane1)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(811, Short.MAX_VALUE)
.addComponent(jButton1)
.addGap(25, 25, 25))
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
Platform.runLater(new Runnable() {
#Override
public void run() {
initFX(fxPanel);
jScrollPane1.add(fxPanel);
}
});
}
/**
* #param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(VisualizzaFattureXML.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(VisualizzaFattureXML.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(VisualizzaFattureXML.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(VisualizzaFattureXML.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new VisualizzaFattureXML().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JScrollPane jScrollPane1;
// End of variables declaration
}

Don't add() the fxPanel to the JScrollPane. Instead, invoke setViewportView():
jScrollPane1.setViewportView(fxPanel);
A complete example may be seen here. Also, don't invoke initFX() in your button handler. Finally, consider the approach outlined here to minimize your reliance on the GUI editor.

Java Jframe is displaying but the contents (Panel) is not showing properly

I've developed a small application to track my daily work activities, this tool contains two classes:
Executor
UIProgress
My objective was to create a ProgressBar which updates the status of the execution, the logic used is given below,
From executeTask () defined in Executor class, I'have created
UIProgress object.
The UIProgress class extends JFrame. Create a panel which contains
a label with one image and the progress bar. I've defined a
method updateProgress in this class which set the value for
progressbar.
In executeTask () method (in Executor class), created UIProgress
object. In executeTask (), am calling different functions to execute
the tasks and after each function am invoking
UIProgress.updateProgress () method with integer vale to update progressbar.
But while running the program, the JFrame UI is transparent means it didn't show the contents instead contains the background data in the frame, Only progressbar is showing and it updating but the entire JFrame is transparent. We are not seeing the panel (image) and it shows as a transparent mode.
Note: setVisible (true) called after added panel into JFrame.
Executor.java
public void executeTask ()
{
/* Create and display the form */
progress = new UIProgress();
progress.prepareGUI();
progress.updateProgress (10);
getWorkedItems ();
//progress.pack ();
progress.updateProgress (30);
getWorkedTickets ();
progress.updateProgress (50);
getRemainTickets ();
progress.updateProgress (70);
jf.postTriagedTicketDetailsDaily();
...
}
UIProgress.java
public class UIProgress extends javax.swing.JFrame {
public UIProgress() {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
initComponents();
}
private void initComponents() {
panelHeading = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
progress_cntrl = new javax.swing.JProgressBar();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
panelHeading.setBackground(new java.awt.Color(204, 204, 204));
panelHeading.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0)));
panelHeading.setDebugGraphicsOptions(javax.swing.DebugGraphics.NONE_OPTION);
panelHeading.setOpaque(false);
jLabel1.setBackground(new java.awt.Color(0, 0, 0));
jLabel1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/devtriagerepot_daily/Background-20.jpeg"))); // NOI18N
javax.swing.GroupLayout panelHeadingLayout = new javax.swing.GroupLayout(panelHeading);
panelHeading.setLayout(panelHeadingLayout);
panelHeadingLayout.setHorizontalGroup(
panelHeadingLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, panelHeadingLayout.createSequentialGroup()
.addContainerGap(29, Short.MAX_VALUE)
.addComponent(progress_cntrl, javax.swing.GroupLayout.PREFERRED_SIZE, 651, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(27, 27, 27))
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 0, Short.MAX_VALUE)
);
panelHeadingLayout.setVerticalGroup(
panelHeadingLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(panelHeadingLayout.createSequentialGroup()
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 147, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(26, 26, 26)
.addComponent(progress_cntrl, javax.swing.GroupLayout.PREFERRED_SIZE, 40, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(0, 31, Short.MAX_VALUE))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(panelHeading, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(0, 4, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(panelHeading, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
);
getAccessibleContext().setAccessibleParent(this);
pack();
}
public void prepareGUI ()
{
progress_cntrl.setMaximum(120);
progress_cntrl.setStringPainted(true);
Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
int x = (int) ((dimension.getWidth() - this.getWidth()) / 2);
int y = (int) ((dimension.getHeight() - this.getHeight()) / 2);
this.setLocation(x, y);
pack ();
setVisible(true);
}
public void updateProgress (int val)
{
progress_cntrl.update(progress_cntrl.getGraphics());
progress_cntrl.setValue(val);
}

The key is likely in these methods here:
getWorkedItems ();
getWorkedTickets ();
getRemainTickets ();
If they take any time to perform at all, your calling them on the Swing event thread will block the thread and freeze your GUI completely, rendering it unable to draw itself properly. The solution is to call any long-running methods in a background thread, such as a SwingWorker's doInBackground() method, and make Swing calls only on the Swing event thread. Again a SwingWorker would work well for this, and in fact it has its own "bound" progress property that can be used. Within the worker simply call setProgress(value) where value is your int from 0 to 100. Then attach a PropertyChangeListener to the worker so that the GUI can be notified of these changes when the progress property is updated.
A caveat: be sure to listen for the worker to finish its run so that you can call get() on the worker as this ill allow you to trap and respond to any exceptions that might have been called during its run.
For example, your code could look something like:
public void executeTask() {
progress = new UIProgress();
progress.prepareGUI();
final SwingWorker<Void, Void> myWorker = new SwingWorker<Void, Void>() {
#Override
protected Void doInBackground() throws Exception {
// progress.updateProgress (10);
setProgress(10); // sets the worker's "bound" progress property
getWorkedItems();
setProgress(30);
getWorkedTickets();
setProgress(50);
getRemainTickets();
setProgress(70);
// ... only further background work goes here
// no direct Swing calls
return null;
}
};
myWorker.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
// if the progress property has been changed
// get its value and use it to update the GUI
progress.updateProgress((int) evt.getNewValue());
} else if (SwingWorker.StateValue.DONE == evt.getNewValue()) {
// worker is done then here notify the GUI
// perhaps call:
// jf.postTriagedTicketDetailsDaily();
// call get() on worker to catch and handle exceptions
try {
myWorker.get();
} catch (InterruptedException | ExecutionException e) {
// TODO handle the excpetions here
e.printStackTrace();
}
}
}
});
myWorker.execute();
}
Note: code not tested.
Please check out Lesson: Concurrency in Swing
Also check out the Swing Tutorials
If this doesn't solve your problem, then you will likely have to create and post a sscce or a minimal example program/mcve where you condense your code into the smallest bit that still compiles and runs, has no outside dependencies (such as need to link to a database or images), has no extra code that's not relevant to your problem, but still demonstrates your problem.
For example, this small program demonstrates the above code in a working GUI:
import java.awt.*;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import javax.swing.*;
public class TestWorker {
private UIProgress progress;
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
new TestWorker().executeTask();
});
}
public void executeTask() {
progress = new UIProgress();
progress.prepareGUI();
final SwingWorker<Void, Void> myWorker = new SwingWorker<Void, Void>() {
#Override
protected Void doInBackground() throws Exception {
// progress.updateProgress (10);
setProgress(10); // sets the worker's "bound" progress property
getWorkedItems();
setProgress(30);
getWorkedTickets();
setProgress(50);
getRemainTickets();
setProgress(70);
TimeUnit.SECONDS.sleep(2);
// ... only further background work goes here
// no direct Swing calls
return null;
}
};
myWorker.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
// if the progress property has been changed
// get its value and use it to update the GUI
progress.updateProgress((int) evt.getNewValue());
} else if (SwingWorker.StateValue.DONE == evt.getNewValue()) {
// worker is done then here notify the GUI
progress.updateProgress(100);
// perhaps call:
// jf.postTriagedTicketDetailsDaily();
// call get() on worker to catch and handle exceptions
try {
myWorker.get();
} catch (InterruptedException | ExecutionException e) {
// TODO handle the exceptions here
e.printStackTrace();
}
}
}
});
myWorker.execute();
}
// dummy methods just to demonstrate long-running code
private void getRemainTickets() {
mySleep(3); // emulate long-running code
}
private void getWorkedTickets() {
mySleep(4);
}
private void getWorkedItems() {
mySleep(2);
}
private void mySleep(int seconds) {
try {
TimeUnit.SECONDS.sleep(seconds);
} catch (InterruptedException e) {}
}
#SuppressWarnings("serial")
private class UIProgress extends JPanel {
private static final int PREF_W = 400;
private static final int PREF_H = 100;
private JProgressBar progressBar = new JProgressBar(0, 100);
private JLabel statusLabel = new JLabel(" ");
public UIProgress() {
JPanel statusPanel = new JPanel(new FlowLayout(FlowLayout.LEADING, 0, 0));
statusPanel.add(new JLabel("Status:"));
statusPanel.add(Box.createHorizontalStrut(4));
statusPanel.add(statusLabel);
setLayout(new BorderLayout());
setBorder(BorderFactory.createEmptyBorder(3, 3, 3, 3));
add(statusPanel, BorderLayout.PAGE_START);
add(progressBar, BorderLayout.PAGE_END);
}
public void prepareGUI() {
JFrame frame = new JFrame("UI Progress");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(this);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
public void updateProgress(int prog) {
String text = String.format("Current Progress is %d%%", prog);
statusLabel.setText(text);
progressBar.setValue(prog);
}
}
}

Java - How to make a form return a value?

Bear in mind I'm a complete (2 weeks) java beginner, and might need things explained as if to a three year old.
I've created a form which is called by the main class. It calls an arrayList of six objects from another class and displays the first four values on buttons.
The sixth item is a string 'qText' displayed on a text pane, while the fifth isn't displayed. So far so good.
pressing the a button should assign a value of 0, 1, 2, or 3 to variable 'qans'.
I would like to be able to check whether 'qans' has the same value as variable 'ans' and return either an int or bool to the main class.
package lp2;
import java.util.ArrayList;
/**
*
* #author david
*/
public class form extends javax.swing.JFrame {
ArrayList set = methods.getquestion();
int a = (int) set.get(0);
int b = (int) set.get(1);
int c = (int) set.get(2);
int d = (int) set.get(3);
int ans = (int) set.get(4);
int qans;
int check = (int) set.get(qans);
String qText = (String) set.get(5);
String stringA = String.valueOf(a);
String stringB = String.valueOf(b);
String stringC = String.valueOf(c);
String stringD = String.valueOf(d);
String stringAns = String.valueOf(ans);
/**
* Creates new form form
*/
public form() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
jTextArea1 = new javax.swing.JTextArea();
btnA = new javax.swing.JButton();
btnB = new javax.swing.JButton();
btnC = new javax.swing.JButton();
btnD = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jTextArea1.setEditable(false);
jTextArea1.setColumns(20);
jTextArea1.setFont(new java.awt.Font("Dialog", 1, 14)); // NOI18N
jTextArea1.setRows(5);
jTextArea1.setText(qText);
jScrollPane1.setViewportView(jTextArea1);
btnA.setText(stringA);
btnA.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnAActionPerformed(evt);
}
});
btnB.setText(stringB);
btnB.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnBActionPerformed(evt);
}
});
btnC.setText(stringC);
btnC.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnCActionPerformed(evt);
}
});
btnD.setText(stringD);
btnD.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnDActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jScrollPane1)
.addGroup(layout.createSequentialGroup()
.addGap(22, 22, 22)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(btnA, javax.swing.GroupLayout.PREFERRED_SIZE, 350, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(btnB, javax.swing.GroupLayout.PREFERRED_SIZE, 350, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(btnC, javax.swing.GroupLayout.PREFERRED_SIZE, 350, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(btnD, javax.swing.GroupLayout.PREFERRED_SIZE, 350, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(28, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnA, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnB, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnC, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnD, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(0, 54, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void btnAActionPerformed(java.awt.event.ActionEvent evt) {
int qans =0;
}
private void btnBActionPerformed(java.awt.event.ActionEvent evt) {
int qans = 1; // TODO add your handling code here:
}
private void btnCActionPerformed(java.awt.event.ActionEvent evt) {
int qans = 2; // TODO add your handling code here:
}
private void btnDActionPerformed(java.awt.event.ActionEvent evt) {
int qans = 3; // TODO add your handling code here:
}
/**
* #param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(form.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(form.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(form.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(form.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new form().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton btnA;
private javax.swing.JButton btnB;
private javax.swing.JButton btnC;
private javax.swing.JButton btnD;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
// End of variables declaration
}

Suggestions:
If you want a window, one that does not represent the main application (here your "main class" whatever that is) to return a value, then don't use a JFrame which can never be used in a modal fashion but rather use a modal dialog such as via a modal JDialog.
For this and many other reasons, you should avoid have your GUI classes extend top-level windows such as JFrame (or JDialog for that matter). Instead have your GUI classes produce JPanes, and these can be placed into the top level window that is most appropriate for your need.
You're shadowing your qans variable, so that the field will never change, no matter what button is pushed, meaning you're re-declaring the variable within a method or constructor, and thus creating and setting the state (assigning a value to ) a local variable, and doing this will not change the state of the class instance field. The solution is not to re-declare the variable. So in the action performed methods, change int qans = 1; to qans = 1;, and likewise for all the other similar bits of code.

Take a look at both JFileChooser and JOptionPane, which are both 'forms' ('windows' in java terminology) but return their value in different ways.
JOptionPane has a static method that shows the dialog, waits until it's done, and returns the result immediately.
JFileChooser works by creating an instance (like you do), making it visible (like you do), waits until its done, and after its done you can interrogate the object by invoking 'getter' methods (ask different types of results)
You can mimic either of these but the second is more powerful.
The waiting-until-done part is handled automatically for you if you use a JDialog instead of JFrame.
Some terminology to get you up to speed:
Window - every separate GUI you can make
Frame - a window with title bar, close button, etc
Dialog - a frame which is 'modal'
Modal - means it blocks execution of whatever made it visible, until it is made invisible
getter - a method that returns a field: like public int getQans() { return qans; }
field - a variable defined in the class (your qans, set, etc.)

Swing: JFormattedTextField set to numbers only using Netbeans

I've got a little problem with JFormattedTextField:
I want to set the formatted text fields to numbers only. I've created one with Swing interface on NetBeans.
My code is as follows:
package SerasApp;
import static java.lang.System.*;
import java.text.NumberFormat;
import java.text.ParseException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFormattedTextField;
import javax.swing.text.DefaultFormatterFactory;
import javax.swing.text.MaskFormatter;
import javax.swing.text.NumberFormatter;
/**
* #author adam
*/
public class Main extends javax.swing.JFrame {
/**
* Creates new form Main
*/
public Main() {
initComponents();
}
//set position of label to be the center of the frame
public void PositionHiSera()
{
//find position of jpanel
int FrameHeight = this.Intro.getHeight();
int FrameWidth = this.Intro.getWidth();
int LabelSize[] = new int[2];
LabelSize[0] = HiSera.getWidth();
LabelSize[1] = HiSera.getHeight();
out.println(LabelSize[0]);
out.println(LabelSize[1]);
int Origin[] = new int[2];
Origin[1] = (FrameHeight/2)-(LabelSize[0]/2);
Origin[0] = (FrameWidth/2)-(LabelSize[1]/2);
//set label origin
HiSera.setLocation(Origin[1], Origin[0]);
}
public void HumidityLevel()
{
NumberFormat a = NumberFormat.getNumberInstance();
NumberFormatter b = new NumberFormatter(a);
DefaultFormatterFactory c = new DefaultFormatterFactory(b);
humidityLevel.setFormatterFactory(c);
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
MainDisplayFrame = new javax.swing.JPanel();
Intro = new javax.swing.JPanel();
HiSera = new javax.swing.JLabel();
MainMenu = new javax.swing.JPanel();
WeatherOptions = new javax.swing.JPanel();
sunny = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
humidityLevel = new javax.swing.JFormattedTextField();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
addWindowFocusListener(new java.awt.event.WindowFocusListener() {
public void windowGainedFocus(java.awt.event.WindowEvent evt) {
formWindowGainedFocus(evt);
}
public void windowLostFocus(java.awt.event.WindowEvent evt) {
}
});
MainDisplayFrame.setLayout(new java.awt.CardLayout());
Intro.setMaximumSize(new java.awt.Dimension(30000, 30000));
HiSera.setText("Hi Sera");
javax.swing.GroupLayout IntroLayout = new javax.swing.GroupLayout(Intro);
Intro.setLayout(IntroLayout);
IntroLayout.setHorizontalGroup(
IntroLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(IntroLayout.createSequentialGroup()
.addGap(209, 209, 209)
.addComponent(HiSera)
.addContainerGap(243, Short.MAX_VALUE))
);
IntroLayout.setVerticalGroup(
IntroLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(IntroLayout.createSequentialGroup()
.addGap(225, 225, 225)
.addComponent(HiSera)
.addContainerGap(258, Short.MAX_VALUE))
);
MainDisplayFrame.add(Intro, "card2");
javax.swing.GroupLayout MainMenuLayout = new javax.swing.GroupLayout(MainMenu);
MainMenu.setLayout(MainMenuLayout);
MainMenuLayout.setHorizontalGroup(
MainMenuLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, Short.MAX_VALUE, Short.MAX_VALUE)
);
MainMenuLayout.setVerticalGroup(
MainMenuLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 500, Short.MAX_VALUE)
);
MainDisplayFrame.add(MainMenu, "card2");
WeatherOptions.addFocusListener(new java.awt.event.FocusAdapter() {
public void focusGained(java.awt.event.FocusEvent evt) {
WeatherOptionsFocusGained(evt);
}
});
sunny.setText("Sunny");
sunny.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
sunnyActionPerformed(evt);
}
});
jButton2.setText("Overcast");
jButton3.setText("Rainy");
jLabel1.setText("Humidity Level");
javax.swing.GroupLayout WeatherOptionsLayout = new javax.swing.GroupLayout(WeatherOptions);
WeatherOptions.setLayout(WeatherOptionsLayout);
WeatherOptionsLayout.setHorizontalGroup(
WeatherOptionsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(WeatherOptionsLayout.createSequentialGroup()
.addGroup(WeatherOptionsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(WeatherOptionsLayout.createSequentialGroup()
.addGap(81, 81, 81)
.addComponent(sunny)
.addGap(75, 75, 75))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, WeatherOptionsLayout.createSequentialGroup()
.addContainerGap()
.addComponent(jLabel1)
.addGap(36, 36, 36)))
.addGroup(WeatherOptionsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(humidityLevel, javax.swing.GroupLayout.PREFERRED_SIZE, 178, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(WeatherOptionsLayout.createSequentialGroup()
.addComponent(jButton2)
.addGap(69, 69, 69)
.addComponent(jButton3)))
.addContainerGap(99, Short.MAX_VALUE))
);
WeatherOptionsLayout.setVerticalGroup(
WeatherOptionsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(WeatherOptionsLayout.createSequentialGroup()
.addGap(225, 225, 225)
.addGroup(WeatherOptionsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(sunny)
.addComponent(jButton2)
.addComponent(jButton3))
.addGap(87, 87, 87)
.addGroup(WeatherOptionsLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(humidityLevel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(132, Short.MAX_VALUE))
);
MainDisplayFrame.add(WeatherOptions, "card2");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 500, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(MainDisplayFrame, javax.swing.GroupLayout.DEFAULT_SIZE, 500, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 500, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(MainDisplayFrame, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void formWindowGainedFocus(java.awt.event.WindowEvent evt) {
// TODO add your handling code here:
PositionHiSera();
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
//make Intro Disappear and make Weather Options Appear
WeatherOptions.setVisible(true);
Intro.setVisible(false);
HumidityLevel();
out.println("tests");
}
private void sunnyActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void WeatherOptionsFocusGained(java.awt.event.FocusEvent evt) {
// TODO add your handling code here:
}
/**
* #param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Main().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JLabel HiSera;
private javax.swing.JPanel Intro;
private javax.swing.JPanel MainDisplayFrame;
private javax.swing.JPanel MainMenu;
private javax.swing.JPanel WeatherOptions;
private javax.swing.JFormattedTextField humidityLevel;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JLabel jLabel1;
private javax.swing.JButton sunny;
// End of variables declaration
}
I've tried also to set a humidityLevel to new formatted text field to no avail.
Mainly it's this bit of code:
public void HumidityLevel()
{
NumberFormat a = NumberFormat.getNumberInstance();
NumberFormatter b = new NumberFormatter(a);
DefaultFormatterFactory c = new DefaultFormatterFactory(b);
humidityLevel.setFormatterFactory(c);
}
and this bit:
private void formWindowGainedFocus(java.awt.event.WindowEvent evt) {
// TODO add your handling code here:
PositionHiSera();
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
//make Intro Disappear and make Weather Options Appear
WeatherOptions.setVisible(true);
Intro.setVisible(false);
HumidityLevel();
out.println("tests");
}
I also don't want to use a JTextField because I want to learn how to use JFormattedTextField.

I want to set the formatted text fields to numbers only.
Using the Design view, right click over the formatted text field and choose Properties option. Then look for formatterFactory property:
If you try to edit this property, the following dialog will show up. Choose integer default option under number category:
That's it, your text field will be initialized using NumberFormat.getIntegerInstance(). If you inspect the generated source code you'll see something like this:
jFormattedTextField1 = new javax.swing.JFormattedTextField();
jFormattedTextField1.setFormatterFactory(new javax.swing.text.DefaultFormatterFactory(new javax.swing.text.NumberFormatter(java.text.NumberFormat.getIntegerInstance())));
Off-topic
As #mKorbel pointed out, using Thread.sleep() is a bad idea and will block the Event Dispatch Thread (EDT) which is a single and special thread where Swing components creation / update should be performed and event handling is processed. If this thread is blocked then your GUI won't be able to repaint itself and will "freeze". In this case you should consider use a Swing Timer instead. See Concurrency in Swing for further details.

How to Pause and Resume a Thread in Java from another Thread

I'm writing an application with Java Swing. What i need is a procedure where i can stop the "elaboration" thread using a button in the graphic interface.
Here a simple project focused on what i need
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JTextArea;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* #author Nikola
*/
public class Main extends javax.swing.JFrame
{
private MyThread THREAD;
public Main()
{
initComponents();
}
#SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jButton1 = new javax.swing.JButton();
jScrollPane1 = new javax.swing.JScrollPane();
jTextArea1 = new javax.swing.JTextArea();
jButton2 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jButton1.setText("Pause Thread");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jTextArea1.setColumns(20);
jTextArea1.setRows(5);
jScrollPane1.setViewportView(jTextArea1);
jButton2.setText("Resume Thread");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
jButton3.setText("Start Thread");
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jButton3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 63, Short.MAX_VALUE)
.addComponent(jButton2)
.addGap(18, 18, 18)
.addComponent(jButton1))
.addComponent(jScrollPane1))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 244, Short.MAX_VALUE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2)
.addComponent(jButton3))
.addContainerGap())
);
pack();
}// </editor-fold>
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt)
{
THREAD = new MyThread(jTextArea1);
THREAD.start();
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt)
{
try
{
THREAD.pauseThread();
}
catch (InterruptedException ex)
{
ex.printStackTrace();
}
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt)
{
THREAD.resumeThread();
}
public static void main(String args[])
{
/*
* Set the Nimbus look and feel
*/
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/*
* If Nimbus (introduced in Java SE 6) is not available, stay with the
* default look and feel. For details see
* http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try
{
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels())
{
if ("Nimbus".equals(info.getName()))
{
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
}
catch (ClassNotFoundException ex)
{
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
catch (InstantiationException ex)
{
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
catch (IllegalAccessException ex)
{
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
catch (javax.swing.UnsupportedLookAndFeelException ex)
{
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/*
* Create and display the form
*/
java.awt.EventQueue.invokeLater(new Runnable()
{
public void run()
{
new Main().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
// End of variables declaration
}
class MyThread extends Thread
{
JTextArea area;
private final Object lock = new Object();
public MyThread(JTextArea area)
{
super();
this.area = area;
}
#Override
public void run()
{
for(int i=0 ; ; i++)
area.setText(i+"");
}
public void pauseThread() throws InterruptedException
{
synchronized(lock)
{
lock.wait();
}
}
public void resumeThread()
{
synchronized(lock)
{
lock.notify();
}
}
}
The question is simple:
In the real application, the user set some options and then start the thread which doing the elaboration of the selected data.
I want to provide a "pause" button so the user can stop temporarily the elaboration and make some needed check and after that can resume the operation.
In the way i coded is the graphic thread that stop, not the "elaboration" one.
If you run my sample code and press "Start" the textarea starts to counting. The final result that i need is that when i press the "Pause" button the thread go to "sleep" and the counting stops, when i press the "Resume" button the thread "wakes up" and the counting in the text area starts againt to count.

You can't definitively pause one thread from another in the way you seem to want.
What you need to do instead, is signal that the other thread should stop, by setting some sort of flag. The thread in question must have logic to check this flag and pause its work when that happens.
So in this particular case, perhaps change MyThread as follows:
class MyThread extends Thread {
private volatile boolean running = true; // Run unless told to pause
...
#Override
public void run()
{
for(int i=0 ; ; i++)
{
// Only keep painting while "running" is true
// This is a crude implementation of pausing the thread
while (!running)
yield;
area.setText(i+"");
}
public void pauseThread() throws InterruptedException
{
running = false;
}
public void resumeThread()
{
running = true;
}
}
This is a crude example that for brevity uses a sort of spinlock rather than proper monitor-based sleeping. Hopefully though it communicates the idea of how you use a flag to control the pausing of the thread.
Note that if you were doing some long-running set of steps within the block, instead of just the setText call, it would be good practice to check Thread.currentThread().interrupted() between each of the steps - and exit the loop if the itnerrupt flag is set. This is broadly what the built-in blocking methods (e.g. I/O) do so that they can be interrupted by other threads - since the running flag is only checked one per loop, it doesn't do much good to set it if each loop takes 20 minutes.

Try it like this:
class MyThread extends Thread {
JTextArea area;
private final Object GUI_INITIALIZATION_MONITOR = new Object();
private boolean pauseThreadFlag = false;
public MyThread(JTextArea area) {
super();
this.area = area;
}
#Override
public void run() {
for(int i=0 ; ; i++) {
checkForPaused();
area.setText(i+"");
}
}
private void checkForPaused() {
synchronized (GUI_INITIALIZATION_MONITOR) {
while (pauseThreadFlag) {
try {
GUI_INITIALIZATION_MONITOR.wait();
} catch (Exception e) {}
}
}
}
public void pauseThread() throws InterruptedException {
pauseThreadFlag = true;
}
public void resumeThread() {
synchronized(GUI_INITIALIZATION_MONITOR) {
pauseThreadFlag = false;
GUI_INITIALIZATION_MONITOR.notify();
}
}
}
It is a good idead to use monitors like you did. But you can not force the wait from outside. You have to tell the thread to wait, until you notify him again (over the monitor). In this case, you just have this simple method checkForPaused() that you will have to put in strategic positions so there is not a long delay until the thread is paused.
You can also extend this function so you can ask the thread if he is paused with a flag set in checkForPaused() and a public boolean isPausing().