I have two Java(.java) files. One has a JButton and JTextField and the other has a Thread. In first Java file, I have added an ActionListener to the JButton so that, when the button is pressed, a thread (object for 2nd .java file in created and thread is initiated) runs which modifies an integer variable continuously. How to display the value of that integer variable (of 2nd .java file) in the JTextField (of 1st .java file) ?
Detection.java
package sample;
public class Detection implements Runnable
{
public String viewers;
public int count;
public void run()
{
try
{
while (true)
{
// i have written code for displaying video.
// and it say how many no. of people in the video
// the no of people is stored in a variable "count"
viewers=""+count; //storing count as string so as to display in the JTextField
}
}
catch (Exception e)
{
System.out.println("Exception: "+e);
}
}
}
UsrInterfac.java
//build using WindowBuilder eclipse juno
package sample;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JTextField;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class UsrInterfac
{
private JFrame frame;
private JTextField textField;
Detection dd = new Detection();
Thread th = new Thread(dd);
/**
* Launch the application.
*/
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
try
{
UsrInterfac window = new UsrInterfac();
window.frame.setVisible(true);
}
catch (Exception e)
{
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public UsrInterfac()
{
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 btnStartThread = new JButton("Start Thread");
btnStartThread.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
th.start();
}
});
btnStartThread.setBounds(59, 133, 117, 23);
frame.getContentPane().add(btnStartThread);
textField = new JTextField();
textField.setBounds(270, 134, 104, 20);
frame.getContentPane().add(textField);
textField.setColumns(10);
}
}
Starting from the basics, while using Swing, it is always best to use LayoutManagers, which can make your work much more easier, in comparison to using Absolute Positioning.
Whenever one needs to change something in the View from some another thread, it is always advisable to do that using EventQueue.invokeLater(...)/EventQueue.invokeAndWait(...).
This small sample program, might be able to help you get an idea, how to accomplish what you so desire :-)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ThreadCounter
{
private CustomThread cThread;
private JTextField tField;
private JButton button;
private int counter;
public ThreadCounter()
{
counter = 0;
}
private void displayGUI()
{
JFrame frame = new JFrame("Thread Counter Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
tField = new JTextField(10);
tField.setText("0");
button = new JButton("Start");
button.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
if (counter == 0)
{
cThread = new CustomThread(tField);
cThread.setFlagValue(true);
cThread.start();
counter = 1;
button.setText("Stop");
}
else
{
try
{
cThread.setFlagValue(false);
cThread.join();
}
catch(InterruptedException ie)
{
ie.printStackTrace();
}
counter = 0;
button.setText("Start");
}
}
});
contentPane.add(tField);
contentPane.add(button);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
new ThreadCounter().displayGUI();
}
});
}
}
class CustomThread extends Thread
{
private int changingVariable;
private JTextField tField;
private boolean flag = true;
public CustomThread(JTextField tf)
{
changingVariable = 0;
tField = tf;
}
public void setFlagValue(boolean flag)
{
this.flag = flag;
}
#Override
public void run()
{
while (flag)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
tField.setText(
Integer.toString(
++changingVariable));
}
});
try
{
Thread.sleep(1000);
}
catch(InterruptedException ie)
{
ie.printStackTrace();
}
}
System.out.println("I am OUT of WHILE");
}
}
Ideally you should post your code. Anyway, when you are calling the thread code, either pass the instance of the first class (object) or an instance of JTextField, so that the thread can set the new value in the text field.
Related
I am printing simple value to append JTextArea using simple for loop, and when I run it, it's properly Run if I print value in console output...
But if I append JTextArea and print value in the text area, they are appended all after whole program run.
public class SwingThread {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SwingThread window = new SwingThread();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public SwingThread() {
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);
JScrollPane scrollPane = new JScrollPane();
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JTextArea textArea = new JTextArea();
scrollPane.setViewportView(textArea);
JButton btnNewButton = new JButton("New button");
scrollPane.setColumnHeaderView(btnNewButton);
btnNewButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
try
{
for(int i = 0 ; i <= 5 ; i++)
{
textArea.append("Value "+i+"\n");
System.out.println("Value is" + i);
Thread.sleep(1000);
}
}
catch(Exception e)
{
System.out.println("Error : "+e);
}
}
});
}
}
I want to append one by one, but it was appended after the whole program runs.
Your problem is with your use of Thread.sleep, since when you call this on the Swing event thread (or EDT for Event Dispatch Thread) as you are doing, it will put the entire Swing event thread to sleep. When this happens the actions of this thread cannot be performed, including painting the GUI (updating it) and interacting with the user, and this will completely freeze your GUI -- not good. The solution in this current situation is to use a Swing Timer as a pseudo-loop. The Timer creates a loop within a background thread and guarantees that all code within its actionPerformed method will be called on the Swing event thread, a necessity here since we don't want to append to the JTextArea off of this thread.
Also as others have noted, if all you want to do is to perform a repeated action with delay in Swing, then yes, use this Swing Timer. If on the other hand you wish to run a long-running bit of code in Swing, then again this code will block the EDT and will freeze your program. For this situation use a background thread such as one supplied by a SwingWorker. Please check out Lesson: Concurrency in Swing for more on this.
e.g.,
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
// delay between timer ticks: 1000
int timerDelay = 1000;
new Timer(timerDelay, new ActionListener() {
private int counter = 0;
#Override
public void actionPerformed(ActionEvent e) {
// timer's stopping condition
if (counter >= MAX_VALUE) { // MAX_VALUE is a constant int = 5
((Timer) e.getSource()).stop();
} else {
textArea.append("Value " + counter + "\n");
}
counter++; // increment timer's counter variable
}
}).start();
}
});
The whole thing:
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.*;
import javax.swing.*;
public class SwingThread2 {
protected static final int MAX_VALUE = 5; // our constant
private JFrame frame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SwingThread2 window = new SwingThread2();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public SwingThread2() {
initialize();
}
private void initialize() {
frame = new JFrame();
// frame.setBounds(100, 100, 450, 300); // avoid this
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane = new JScrollPane();
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JTextArea textArea = new JTextArea(15, 40);
scrollPane.setViewportView(textArea);
JButton btnNewButton = new JButton("New button");
scrollPane.setColumnHeaderView(btnNewButton);
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
// delay between timer ticks: 1000
int timerDelay = 1000;
new Timer(timerDelay, new ActionListener() {
private int counter = 0;
#Override
public void actionPerformed(ActionEvent e) {
// timer's stopping condition
if (counter >= MAX_VALUE) { // MAX_VALUE is a constant int = 5
((Timer) e.getSource()).stop();
} else {
textArea.append("Value " + counter + "\n");
}
counter++; // increment timer's counter variable
}
}).start();
}
});
// better to avoid setting sizes but instead to
// let the components size themselves vis pack
frame.pack();
frame.setLocationRelativeTo(null);
}
}
Just for further information, here is an example of the same program above that uses a SwingWorker to perform a long running action, and then update a JProgressBar with this action. The worker is quite simple, and simply uses a while loop to advance a counter variable by a bounded random amount. It then transmits uses this value to update its own progress property (a value that can only be from 0 to 100, and so in other situations, the value will need to be normalized to comply with this). I attach a PropertyChangeListener to the worker, and this is notified on the Swing event thread whenever the worker's progress value changes and also whenever the SwingWorker changes state, such as when it is done operating. In the latter situation, the worker's StateValue becomes StateValue.DONE. The listener then updates the GUI accordingly. Please ask if any questions.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Random;
import java.util.concurrent.ExecutionException;
import javax.swing.*;
public class SwingThread2 {
protected static final int MAX_VALUE = 5; // our constant
private JFrame frame;
private JProgressBar progressBar = new JProgressBar();
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SwingThread2 window = new SwingThread2();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public SwingThread2() {
initialize();
}
private void initialize() {
frame = new JFrame();
// frame.setBounds(100, 100, 450, 300); // avoid this
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scrollPane = new JScrollPane();
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JTextArea textArea = new JTextArea(15, 40);
scrollPane.setViewportView(textArea);
JButton btnNewButton = new JButton("New button");
scrollPane.setColumnHeaderView(btnNewButton);
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
// delay between timer ticks: 1000
int timerDelay = 1000;
new Timer(timerDelay, new ActionListener() {
private int counter = 0;
#Override
public void actionPerformed(ActionEvent e) {
// timer's stopping condition
if (counter >= MAX_VALUE) { // MAX_VALUE is a constant
// int = 5
((Timer) e.getSource()).stop();
} else {
textArea.append("Value " + counter + "\n");
}
counter++; // increment timer's counter variable
}
}).start();
}
});
progressBar.setStringPainted(true);
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.LINE_AXIS));
bottomPanel.add(new JButton(new MyAction("Press Me")));
bottomPanel.add(progressBar);
frame.getContentPane().add(bottomPanel, BorderLayout.PAGE_END);
// better to avoid setting sizes but instead to
// let the components size themselves vis pack
frame.pack();
frame.setLocationRelativeTo(null);
}
private class MyAction extends AbstractAction {
public MyAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
public void actionPerformed(ActionEvent e) {
progressBar.setValue(0);
setEnabled(false);
MyWorker myWorker = new MyWorker();
myWorker.addPropertyChangeListener(new WorkerListener(this));
myWorker.execute();
}
}
private class WorkerListener implements PropertyChangeListener {
private Action action;
public WorkerListener(Action myAction) {
this.action = myAction;
}
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ("progress".equals(evt.getPropertyName())) {
int progress = (int) evt.getNewValue();
progressBar.setValue(progress);
} else if ("state".equals(evt.getPropertyName())) {
if (evt.getNewValue() == SwingWorker.StateValue.DONE) {
action.setEnabled(true);
#SuppressWarnings("rawtypes")
SwingWorker worker = (SwingWorker) evt.getSource();
try {
// always want to call get to trap and act on
// any exceptions that the worker might cause
// do this even though get returns nothing
worker.get();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
}
}
}
private class MyWorker extends SwingWorker<Void, Void> {
private static final int MULTIPLIER = 80;
private int counter = 0;
private Random random = new Random();
#Override
protected Void doInBackground() throws Exception {
while (counter < 100) {
int increment = random.nextInt(10);
Thread.sleep(increment * MULTIPLIER);
counter += increment;
counter = Math.min(counter, 100);
setProgress(counter);
}
return null;
}
}
}
I need to make a slot machine that implements thread in java and jframe
this is what iv'e done so far kindly tell me what i need to do in order make the images change per .5 seconds when i press the the play and stop when i press stop. If all the three images are the same it'll say you won. This is what iv'e got so far how will i change this numbers or text to images in jlabel.
public class MySlotNumber extends JFrame{
private MyJLabel x;
private MyJLabel y;
private MyJLabel z;
private JButton btn;
public MySlotNumber(){
super("ABC");
setLayout(new FlowLayout());
Font font = new Font("arial",Font.ITALIC,50);
x = new MyJLabel();
x.setFont(font);
y = new MyJLabel();
y.setFont(font);
z = new MyJLabel();
z.setFont(font);
btn = new JButton("PLAY");
btn.setFont(font);
add(x);
add(y);
add(z);
add(btn);
final Thread thx = new Thread(x);
final Thread thy = new Thread(y);
final Thread thz = new Thread(z);
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(e.getActionCommand().equals("PLAY")){
if(thx.isAlive()){
thx.resume();
thy.resume();
thz.resume();
} else {
thx.start();
thy.start();
thz.start();
}
btn.setText("STOP");
} else {
thx.suspend();
thy.suspend();
thz.suspend();
btn.setText("PLAY");
System.out.println(x.getText());
}
}
});
}
- - - - - - --
public class MyJLabel extends JLabel implements Runnable{
private Random r;
private int ctr;
private final int T = 500;
public MyJLabel(){
setText("0");
ctr = 0;
r= new Random();
}
#Override
public void run() {
while(true){
try {
Thread.sleep(T);
} catch (InterruptedException ex) {
Logger.getLogger(MyJLabel.class.getName()).log(Level.SEVERE, null, ex);
}
//ctr++;
ctr = r.nextInt(9)+1;
setText(String.valueOf(ctr));
}
}
}
Here is one way to put a picture on a JLabel and change it when you click a button. (I am using window builder for eclipse, so it may look a little odd.) It is not recommended you use absolute paths because when you move your project or the file, it breaks (I did this just for proof of concept).
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.BorderLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class Test {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Test window = new Test();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Test() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 1379, 643);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel lblNewLabel = new JLabel("");
lblNewLabel.setIcon(new ImageIcon("C:\\Users\\Andrew\\Pictures\\Random Pictures\\Capture.JPG"));
frame.getContentPane().add(lblNewLabel, BorderLayout.CENTER);
JButton btnClickMe = new JButton("click me");
btnClickMe.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
lblNewLabel.setIcon(new ImageIcon("C:\\Users\\Andrew\\Pictures\\Random Pictures\\I'm pretty sure he did.JPG"));
}
});
frame.getContentPane().add(btnClickMe, BorderLayout.EAST);
}
}
I'm trying to figure out this for ages, starting to wonder if it is possible!
I have a starting window for my app - I need it so that when I click on a button I have created, the window either closes and opens a new window or the window resizes and leaves just the canvas (ready to put new widgets, sprites etc... ).
I know I need a handler event for this but I just can't get the code to work.
Im not quite sure whats your question but i coded a example with a JFrame and 3 Buttons.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
public class OpenWindowAndResizeWindow
{
private JFrame frame;
private JButton btnOpenNewWindow;
private JButton btnResizeWindow;
private JButton btnRemoveAllButtons;
/**
* Launch the application.
*/
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
try
{
OpenWindowAndResizeWindow window = new OpenWindowAndResizeWindow();
window.frame.setVisible(true);
}
catch (Exception e)
{
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public OpenWindowAndResizeWindow()
{
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize()
{
frame = new JFrame();
frame.setBounds(100, 100, 300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(getBtnOpenNewWindow(), BorderLayout.NORTH);
frame.getContentPane().add(getBtnResizeWindow(), BorderLayout.SOUTH);
frame.getContentPane().add(getBtnRemoveAllButtons(), BorderLayout.CENTER);
frame.setVisible(true);
}
private void openNewWindow()
{
OpenWindowAndResizeWindow newWindow = new OpenWindowAndResizeWindow();
frame.dispose();
}
private void removeButtons()
{
getBtnOpenNewWindow().setVisible(false);
getBtnRemoveAllButtons().setVisible(false);
getBtnResizeWindow().setVisible(false);
}
private void resizeWindow()
{
Rectangle rectangle = frame.getBounds();
rectangle.width = (int)rectangle.getWidth() + 100;
rectangle.height = (int)rectangle.getHeight() + 100;
frame.setBounds(rectangle);
}
private JButton getBtnOpenNewWindow() {
if (btnOpenNewWindow == null) {
btnOpenNewWindow = new JButton("Open new Window");
btnOpenNewWindow.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
openNewWindow();
}
});
}
return btnOpenNewWindow;
}
private JButton getBtnResizeWindow() {
if (btnResizeWindow == null) {
btnResizeWindow = new JButton("Resize Window");
btnResizeWindow.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
resizeWindow();
}
});
}
return btnResizeWindow;
}
private JButton getBtnRemoveAllButtons() {
if (btnRemoveAllButtons == null) {
btnRemoveAllButtons = new JButton("Remove All Buttons");
btnRemoveAllButtons.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
removeButtons();
}
});
}
return btnRemoveAllButtons;
}
}
This code is ready to compile with javac or just paste it in your IDE.
Maybe this helps a bit. The Java SE API Documentation is useful too.
I am trying to make this work. I create a window, with one text field and button, then I run the run() method which should refresh text in textfield, and when I click on button it should iterate number by 1. I want to make this work simultaneously but I am stuck. It just iterates the number but do not refresh a value in textfield.Could you please help me somehow? I thought its easy to learn about Threads but...no :-D Here is the code.
Window class
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
#SuppressWarnings("serial")
public class Okno extends JFrame implements ActionListener,Runnable {
private JFrame o = new JFrame();
private static JTextField t = new JTextField();
private JTextField t2 = new JTextField();
private static int x = 0;
protected JButton b = new JButton("KLIK");
Okno() {
o.setVisible(true);
o.setBounds(0, 0, 300, 200);
o.setLayout(null);
o.setDefaultCloseOperation(EXIT_ON_CLOSE);
t.setBounds(10, 10, 60, 20);
t2.setBounds(80, 10, 60, 20);
b.setBounds(50, 80, 60, 30);
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
while (true) {
Okno.work();
System.out.println("Klik");
}
}
});
o.add(t);
o.add(b);
o.add(t2);
}
public static int iter(){
x++;
return x;
}
public static void work(){
try {
iter();
System.out.println(x);
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void actionPerformed(ActionEvent e) {
}
#Override
public void run() {
while(true){
try {
Thread.sleep(1200);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
t.setText(Integer.toString(x));
System.out.println("RUN");
}
}
}
Main Class
public class ThreadDemo {
public static void main(String args[]) {
Okno o = new Okno();
while(true){
o.run();
}
}
}
Swing is single threaded. Calling Thread.sleep prevents UI updates. Use a Swing Timer instead.
From GETah's answer to java stopwatch that updates gui every second:
Something along these lines should do it:
import java.awt.EventQueue;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JFrame;
import javax.swing.JLabel;
/** #see https://stackoverflow.com/a/11058263/230513 */
public class Clock {
private Timer timer = new Timer();
private JLabel timeLabel = new JLabel(" ", JLabel.CENTER);
public Clock() {
JFrame f = new JFrame("Seconds");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(timeLabel);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
timer.schedule(new UpdateUITask(), 0, 1000);
}
private class UpdateUITask extends TimerTask {
int nSeconds = 0;
#Override
public void run() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
timeLabel.setText(String.valueOf(nSeconds++));
}
});
}
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
final Clock clock = new Clock();
}
});
}
}
The timeLabel will always display the number of seconds the timer
has been running.
You will need to correctly format it to display "hh:mm:ss"; one approach is shown here.
Create a container and add the label to it so that you can display it as part of the GUI.
Compare the result to this alternate using javax.swing.Timer.
1) how can I set Cursor to 0 possition without using Caret or Focus wrapped into invokeLater() (confortly can be solved by using #camickr Formatted Text Field Tips), is there somebody who knows another way
2) How to reset Formatter sometimes (by raising Focus by TAB from keyboard), reset doesn't works and on focusLost (empty field) Formatter returns/reincarnated chars or String back (last know before setText("");),
Note: know code or following code is only this way, about how to reset Formatter from OTN, but their terrible search rulles ...., only code (question or answer by Jeanette???)
import java.awt.event.*;
import java.beans.*;
import java.text.ParseException;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.Document;
public class FormattedNull {
private JFormattedTextField field;
private JButton focusButton;
private JComponent createContent() {
JComponent content = new JPanel();
field = new JFormattedTextField(new Integer(55));
field.setColumns(20);
field.addPropertyChangeListener(getPropertyChangeListener());
field.getDocument().addDocumentListener(getDocumentListener());
content.add(field);
focusButton = new JButton("just something focusable");
focusButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
field.setValue(0);
field.requestFocusInWindow();
}
});
content.add(focusButton);
return content;
}
protected void maybeCommitEdit(Document document) {
try {
field.commitEdit();
} catch (ParseException e) {
// uncomment to map empty string to null
if (field.getText().length() == 0) {
field.setValue(null);
}
}
}
/*public void commitEdit() throws ParseException {
if(allowsNull() && isBlank()) {
setValue(null);
}
else {
super.commitEdit();
}
}*/
private PropertyChangeListener getPropertyChangeListener() {
PropertyChangeListener propertyChangeListener = new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ("value".equals(evt.getPropertyName())) {
matchValueChanged(evt.getNewValue());
}
}
};
return propertyChangeListener;
}
protected void matchValueChanged(Object value) {
System.out.println("got new value: " + value);
}
private DocumentListener getDocumentListener() {
DocumentListener documentListener = new DocumentListener() {
#Override
public void removeUpdate(DocumentEvent e) {
maybeCommitEdit(e.getDocument());
}
#Override
public void insertUpdate(DocumentEvent e) {
maybeCommitEdit(e.getDocument());
}
#Override
public void changedUpdate(DocumentEvent e) {
}
};
return documentListener;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new FormattedNull().createContent());
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
}
});
}
}
attached images are based on my sscce
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import javax.swing.*;
import javax.swing.text.MaskFormatter;
public class TestTest {
private JFormattedTextField myFormattedField1 = new JFormattedTextField(createFormatter("AAAAAAAAAAAA"));
private JFormattedTextField myFormattedField2 = new JFormattedTextField(createFormatter("AAAAAAAAAAAA"));
private JFormattedTextField myFormattedField3 = new JFormattedTextField(createFormatter("AAAAAAAAAAAA"));
private JFormattedTextField myFormattedField4 = new JFormattedTextField(createFormatter("AAAAAAAAAAAA"));
private JButton jb = new JButton("Reset to Default");
private JFrame frame = new JFrame("Text Test");
public TestTest() {
myFormattedField1.setText("ABCDEFGHIJKL");
myFormattedField2.setText("ABCDEFGHIJKL");
myFormattedField3.setText("ABCDEFGHIJKL");
myFormattedField4.setText("ABCDEFGHIJKL");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(150, 150);
frame.setLayout(new GridLayout(5, 0));
frame.add(jb);
frame.add(myFormattedField1);
frame.add(myFormattedField2);
frame.add(myFormattedField3);
frame.add(myFormattedField4);
jb.addActionListener(new java.awt.event.ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
myFormattedField1.setText("");
myFormattedField2.setText("");
myFormattedField3.setText("");
myFormattedField4.setText("");
}
});
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
TestTest textTest = new TestTest();
}
protected MaskFormatter createFormatter(String s) {
MaskFormatter formatter = null;
try {
formatter = new MaskFormatter(s);
} catch (java.text.ParseException exc) {
System.err.println("formatter is bad: " + exc.getMessage());
}
return formatter;
}
}
On Mac OS, the default behavior of the UI delegate, com.apple.laf.AquaTextFieldF, is similar to CaretPositionListener:
Tab or Shift-Tab: place the caret at the beginning of the field.
Click: briefly place the caret at the beginning of the field and then move it to the click point.
IMO, the CaretPositionListener does the latter much more smoothly.
The default behavior of JFormattedTextField on focus lost is COMMIT_OR_REVERT. In the example below, Tab though the first, invalid field to see the effect. The formatter can neither commit nor revert to the invalid value, so it substitutes MASK.length() spaces. This value is valid, if a little obscure.
Addendum: I've updated the code below to allow changing the setFocusLostBehavior().
Code:
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.text.MaskFormatter;
/** #see http://stackoverflow.com/questions/7378821 */
public class TrashTest {
private static final String MASK = "########";
private static final String DEFAULT = "01234567";
private static final String BOGUS = "0123456";
private JFormattedTextField jtf1 = createField();
private JFormattedTextField jtf2 = createField();
private JFormattedTextField jtf3 = createField();
private JFormattedTextField jtf4 = createField();
private JButton reset = new JButton("Reset to Default");
private JComboBox combo = new JComboBox();
private JFrame frame = new JFrame("Text Test");
public TrashTest() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(150, 150);
frame.setLayout(new GridLayout(0, 1));
frame.add(reset);
frame.add(jtf1);
frame.add(jtf2);
frame.add(jtf3);
frame.add(jtf4);
frame.add(combo);
this.initFields();
reset.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
initFields();
}
});
for (Edit e : Edit.values()) {
combo.addItem(e);
}
combo.setSelectedIndex(jtf1.getFocusLostBehavior());
combo.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Edit current = (Edit) combo.getSelectedItem();
jtf1.setFocusLostBehavior(current.value);
}
});
frame.pack();
frame.setVisible(true);
}
private void initFields() {
jtf1.setText(BOGUS);
jtf2.setText(DEFAULT);
jtf3.setText(DEFAULT);
jtf4.setText(DEFAULT);
}
protected JFormattedTextField createField() {
MaskFormatter formatter = null;
try {
formatter = new MaskFormatter(MASK);
} catch (java.text.ParseException e) {
e.printStackTrace(System.out);
}
JFormattedTextField jtf = new JFormattedTextField(formatter);
return jtf;
}
enum Edit {
COMMIT(JFormattedTextField.COMMIT),
COMMIT_OR_REVERT(JFormattedTextField.COMMIT_OR_REVERT),
REVERT(JFormattedTextField.REVERT),
PERSIST(JFormattedTextField.PERSIST);
private int value;
private Edit(int n) {
this.value = n;
}
public static Edit getEnum(int n) {
for (Edit e : Edit.values()) {
if (e.value == n) {
return e;
}
}
return Edit.COMMIT_OR_REVERT;
}
}
public static void main(String[] args) {
TrashTest textTest = new TrashTest();
}
}