Develop Reference

Java loading gif freeze while processing data?

I call a method which lists all the files in a directory, and adds them to a JTable:
addFilesWithSubsButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
reverseLoadingVisibility(loaderLabel); //set Visible
addFilesWithSubs2(chooser, loaderLabel);
}
});
public void addFilesWithSubs2(JFileChooser chooser, JLabel loaderLabel) {
//loading all files ....
//when every file is listed:
//Set invisible
reverseLoadingVisibility(loaderLabel);
}
The another method change reverse the visibility of the JLabel in which the loading .gif is.
public void reverseLoadingVisibility(JLabel loaderLabel) {
loaderLabel.setVisible(!loaderLabel.isVisible());
}
The problem is: the gif doesn't play, freezes while the files are added to the JTable.
UPDATE: Still have problem the loading gif freezes
addFilesButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
reverseLoadingVisibility(loaderLabel);
try {
new AddFiles().doInBackground(
chooser, CHOOSERTITLE,
lastDictionary,
sdf,
filesTable,
model,
columnNames,
loaderLabel);
} catch (Exception e) {
e.printStackTrace();
}
}
});
public class AddFiles extends SwingWorker{
#Override
protected Void doInBackground() throws Exception {
return null;
}
protected void doInBackground(JFileChooser chooser, String CHOOSERTITLE,
String lastDictionary,
SimpleDateFormat sdf,
JTable filesTable,
DefaultTableModel model,
String[] columnNames,
JLabel loaderLabel) throws Exception {
//Set visible
reverseLoadingVisibility(loaderLabel);
chooser.setDialogTitle(CHOOSERTITLE);
chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
//
chooser.setAcceptAllFileFilterUsed(true);
//TODO: this changed to chooser
if (chooser.showOpenDialog(chooser) == JFileChooser.APPROVE_OPTION) {
// create a file that is really a directory
File aDirectory = new File(chooser.getSelectedFile().toString());
lastDictionary = chooser.getSelectedFile().toString();
// get a listing of all files in the directory
String[] filesInDir = aDirectory.list();
// TODO
System.out.println("Number of files: " + filesInDir.length);
// have everything i need, just print it now
for ( int i=0; i<filesInDir.length; i++ )
{
File currentFile = new File(aDirectory + "\\" + filesInDir[i]);
System.out.println(filesInDir[i] );
System.out.println(aDirectory );
System.out.println(currentFile.length()/1024 + " KB");
System.out.println(sdf.format((currentFile).lastModified()));
// Avoid duplicates
int row = 0;
boolean duplicate = false;
for (; row < filesTable.getRowCount(); row++) {
if (model.getValueAt(row, 1).equals(filesInDir[i]) &&
model.getValueAt(row, 3).equals(aDirectory)
) {
duplicate = true;
break;
}
System.out.println("model.getValueAt(row, 1) " + model.getValueAt(row, 1));
System.out.println(filesInDir[i]);
System.out.println("model.getValueAt(row, 3) " + model.getValueAt(row, 3));
System.out.println(aDirectory);
}
if (!duplicate && currentFile.isFile()) {
model.addRow(new Object[]{
filesTable.getRowCount()+1,
filesInDir[i],
null,
aDirectory,
currentFile.length()/1024 + " KB",
sdf.format((currentFile).lastModified())
});
}
}
}
else {
System.out.println("No Selection ");
}
// Readjust columns
adjustTableColumns(filesTable, columnNames);
//Set unvisible
reverseLoadingVisibility(loaderLabel);
}
...

That's why because all files are loaded in the EDT (Event Dispatch Thread) (hopefully you launch your application using SwingUtilities.invokerLater() method) which cause all swing components to freeze. For more details read this java document by oracle: Initial Threads.
In order to solve your problem, you have to use a SwingWorker. A class responsible for heavy background tasks in Swing applications. With a simple google search, you can take an idea from here: How do I use SwingWorker in Java?
UPDATE in order to answer OP's comment.
The truth is that your code is a little bit big, and the most important, it is not an SSCCE.
In order to give you one more hand to find the solution you are looking for, i have created an SSCCE, using a SwingWorker that does something "heavy". In our case, the something heavy, is to write 1000 lines in a .txt file, but each line, thread (our worker) will sleep for 10ms.
Take it a look, run it if you want (i recommend it). Some extra comments inside the code, do not forget to check them.
package test;
import java.awt.BorderLayout;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
public class SwingWorkerExample extends JFrame {
/*
* Worker has Void doInBackground a.k.a, doInBackground method needs to return nothing.
* Worker needs to process-publish Integers.
*/
private SwingWorker<Void, Integer> writeToFileWorker = null;
private JLabel gifLabel;
private JButton doSomethingHeavy;
public SwingWorkerExample() {
super("Just a test.");
createWorker();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setLayout(new BorderLayout());
gifLabel = new JLabel();
ImageIcon gif = new ImageIcon("C:/Users/George/Desktop/giphy.gif");
gifLabel.setIcon(gif);
gifLabel.setVisible(false); //Initialy non visible
gifLabel.setHorizontalTextPosition(JLabel.CENTER);
gifLabel.setVerticalTextPosition(JLabel.BOTTOM);
gifLabel.setHorizontalAlignment(JLabel.CENTER);
getContentPane().add(gifLabel, BorderLayout.CENTER);
doSomethingHeavy = new JButton("Do something heavy in another thread and start dancing...");
doSomethingHeavy.addActionListener(e -> {
//Before start the worker, show gif and disable the button
doSomethingHeavy.setEnabled(false);
gifLabel.setVisible(true);
writeToFileWorker.execute();
});
getContentPane().add(doSomethingHeavy, BorderLayout.PAGE_END);
setSize(500, 300);
setLocationRelativeTo(null);
}
private void createWorker() {
writeToFileWorker = new SwingWorker<Void, Integer>() {
#Override
protected Void doInBackground() throws Exception {
File fileToWrite = new File(System.getProperty("user.home") + File.separator + "Desktop" + File.separator + "hello_worlds.txt");
try (BufferedWriter writer = new BufferedWriter(new FileWriter(fileToWrite));) {
for (int line = 0; line < 1000; line++) {
writer.append("Hello World! My name is Swing Worker.");
writer.append(System.lineSeparator());
Thread.sleep(10);
publish(line);
}
}
return null;
}
/*
* Runs in Event Dispatch Thread (EDT)
*/
#Override
protected void process(List<Integer> chunks) {
int line = chunks.get(0);//First parameter is the line
gifLabel.setText("Written " + line + " lines in the txt.");
super.process(chunks);
}
/*
* Runs in Event Dispatch Thread (EDT)
*/
#Override
protected void done() {
//When swing worker is finished, a.k.a the heavy work, stop the gif and enable the button
gifLabel.setVisible(false);
doSomethingHeavy.setEnabled(true);
super.done();
}
};
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
SwingWorkerExample swe = new SwingWorkerExample();
swe.setVisible(true);
});
}
}
Small preview:

My guess would be that your addFilesWithSubs2-Method is blocking the UI thread. If you have long running tasks, than you have to execute them in a separate thread e.g. SwingWorker

Java mouse listener: toggle version "click counter"

I'm trying to make a basic click counter using mouse events in Java. I understand the tutorials everyone has but their programs are semi automatic and it registers one increment per click.
public void mouseClicked(MouseEvent e)
{
clicks++;
}
I'm trying to do a fully automatic version of that where it will continually increment until you release the button, but the release method doesn't switch the boolean to false and stop the loop. Any advice?
public class example{
private boolean fire = false;
public void mousePressed(MouseEvent e)
{
if(e.getButton()== e.BUTTON1){fire = true};
while(fire) {clickCounter++; }
}
}
public void mouseReleased(MouseEvent e){
fire = false;
}
}

Just to be clear, a "click" is what typically happens between the mouse been pressed and released, the idea that there are more "clicks" during this period is an artificial construct.
First, you need to go read Concurrency in Swing to better understand while "sleep" and while-loop won't work in this context. You're blocking the Event Dispatching Thread, preventing any new events from been processed.
The following example simply attempts to calculate the time between the mouse pressed and released event and applies a artificial multiplier to the result to create the "click" count
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.time.Duration;
import java.time.LocalDateTime;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
JLabel label = new JLabel("...");
add(label);
addMouseListener(new MouseAdapter() {
private LocalDateTime clickTime;
#Override
public void mouseClicked(MouseEvent e) {
clickTime = LocalDateTime.now();
}
#Override
public void mouseReleased(MouseEvent e) {
if (clickTime == null) {
return;
}
Duration between = Duration.between(clickTime, LocalDateTime.now());
long seconds = between.getSeconds();
long clicks = seconds * 3;
label.setText("Held for " + seconds + "s = " + clicks + " clicks");
clickTime = null;
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}
Another solution might be to start a Swing Timer on mouse pressed and stop it on mouse released, allowing it to increment a value

You set fire= true then enter into an infinite while(true) loop.
To fix this, modify the boolean statement of the while loop inside the loop itself.
while(fire) {
count++;
if (mouseReleased(eventMouseIsReleased))
fire= false;
} // Check while(fire) but now it is false! Move on!
Hope this helps!

Implementing GUI with Java application

I'm quite the beginner when it comes to java & coding in general, so I apologise for any overly obvious questions asked. I've just completed part of an application which reads data from an SQL database, then sends some stuff to print to socket depending on what information is read. I'm now trying to learn swing and get a GUI working with the application. Currently I have 2 forms, the first is used to select a printer, then the second will (hopefully) work as a log/ console which tells the user what and when stuff is happening. I've got the code and the forms together in a project.
I was wanting to find out how I can make the class which has my code in run when a Jbutton is pressed on a GUI, as well as how I can stop it from running when a different JButton is pressed.
The code from the Swing Form (Form2.java) is as follows:
package com.company;
import javax.swing.*;
public class Form2
{
private JTextArea jtaConsole;
private JPanel Jframer;
private JButton stopButton;
private JButton startButton;
public Form2(String message)
{
JFrame frame = new JFrame("Print Application");
frame.setContentPane(this.Jframer);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setResizable(true);
frame.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
jtaConsole.append(" Printer selected: " + message + "\n");
}
}
And the code from the class I want the JButton to run is as follows:
package com.company;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.sql.*;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
public class ZebraCode
{
public static void main(String[] args)
{
{
while (true)
{
//SQL login.
String connectionString = "jdbc:sqlserver://:;database=;user=;password=!!;";
//Select Data.
String SQL = "SELECT TOP 2 [PK_PrintQueueID],[FK_PrinterID],[FK_BarcodeTypeID],[Barcode],[Quantity],[QueueDate],[ProcessedDate] FROM [Brad].[dbo].[PrintQueue] -- WHERE ProcessedDate IS NULL";
//Connection Variable & Time Settings.
Connection connection = null;
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date = new Date();
try
{
connection = DriverManager.getConnection(connectionString);
Statement stmt = connection.createStatement();
Statement stmt2 = null;
ResultSet rs = stmt.executeQuery(SQL);
while (rs.next())
{
// Get barcode value to split & Set date.
String FK_BarcodeTypeID = rs.getString("FK_BarcodeTypeID");
String barcode = rs.getString("Barcode");
String[] parts = barcode.split("-");
String part1 = parts[0];
String SQL2 = "UPDATE PrintQueue SET ProcessedDate = '" + dateFormat.format(date) + "' WHERE PK_PrintQueueID = '" + rs.getString("PK_PrintQueueID")+"'";
stmt2 = connection.createStatement();
stmt2.executeUpdate(SQL2);
// Action based on type of barcode.
if (FK_BarcodeTypeID.equals("1"))
{
// Type 128 barcode.
String zpl = "^XA^BY2,3,140^FT80,200^BCN,Y,N,N^FD>:" + rs.getString("Barcode") + "^FS^FT200,250^A0N,42,40^FH^FD" + part1 + "^FS^XZ";
printlabel(zpl);
System.out.println("New serialized barcode added.\nPrinting: " + (rs.getString("Barcode")));
System.out.println("Process date: " + dateFormat.format(date) + ".\n");
}
else
{
// Type 39 barcode.
String zpl = "CT~~CD,~CC^~CT~ ^XA~TA000~JSN^LT0^MNW^MTT^PON^PMN^LH0,0^JMA^PR4,4~SD15^JUS^LRN^CI0^XZ^XA^MMT^PW674^LL0376 ^LS0 ^BY2,3,151^FT84,249^BCN,,Y,N^FD>:" + rs.getString("Barcode") + "^FS ^PQ1,0,1,Y^XZ";
printlabel(zpl);
System.out.println("New un-serialized barcode added.\nPrinting: " + (rs.getString("Barcode")));
System.out.println("Process date: " + dateFormat.format(date) + ".\n");
}
}
} catch (SQLException e)
{
e.printStackTrace();
}
try
{
//Makes execution sleep for 5 seconds.
Thread.sleep(5000);
}
catch (InterruptedException ez)
{
}
}
}
}
//Printer Info.
public static void printlabel(String zpl)
{
try
{
Socket clientSocket;
clientSocket = new Socket("", );
DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
outToServer.writeBytes(zpl);
clientSocket.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
Any tutorials or direction as to how I can learn this would be appreciated.
Thanks!

You want to add an action listener.. here is an example. Below are two examples on how to do so using lambdas and not using one.
JButton button = new JButton("Click Me!");
// Without lambda
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// Code to execture when clicked
}
});
//With lambda
button.addActionListener(e -> {
//code to execute when clicked
});
I'd also advise you to do a little reading, http://www.tutorialspoint.com/design_pattern/mvc_pattern.htm

Your question is a bit broad but let me offer some suggestions:
First off, you really don't want to have a JButton run the database code unchanged as doing this would be shoehorning a linear console program into an event-driven GUI, a recipe for disaster. Note that as written all your database code is held within a single static main method, and so there would be no way for the GUI to be able to control the running of that code. Either it runs or it doesn't, that's it, and no easy way for the database code to return its data to the GUI.
Instead first change that database code so that it is much more modular and OOP-friendly, including creating proper classes with state (instance fields) and behavior (instance methods), and getting almost all that code out of the static main method.
What I'm asking you to do is to create a proper model for your GUI, aka your view. Only after doing this would you have your GUI create a model object and call its methods on button push within your ActionListener. You will also want to call any long-running code within a background thread such as can be obtained with a SwingWorker.
Other issues:
You never initialize your JPanel or JTextArea variables, and so you're both adding a null variable as your JFrame's JPanel and calling methods on a null JTextArea variable, both of which will throw NullPointerExceptions.

Here's a part of code I developed to better understand Java gui. I'm also a begginer.
It's three classes: starter class, ongoing non gui processes, gui with the swingworker method. Simple, works, can safely update a lot of gui components from Swingworkers process method (passes a class instance as argument). Whole code so it can be copy/pasted:
package structure;
public class Starter {
public static void main(String[] args) {
Gui1 thegui = new Gui1();
}
}
LOGIC
package structure;
public class Logical {
String realtimestuff;
public String getRealtimestuff() {
return realtimestuff;
}
public void setRealtimestuff(String realtimestuff) {
this.realtimestuff = realtimestuff;
}
//MAIN LOGICAL PROCESS..
public void process(){
// do important realtime stuff
if (getRealtimestuff()=="one thing"){
setRealtimestuff("another thing");
}else{setRealtimestuff("one thing");
}
// sleep a while for readibility of label in GUI
//System.out.println(getRealtimestuff());
try {
Thread.sleep(250);
} catch (InterruptedException e) {
System.out.println("sleep interrupted");
return;
}
}
}
GUI CLASS with Swingworker
package structure;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JLabel;
import java.util.List;
import javax.swing.*;
public class Gui1 {
final class Dataclass{
String stringtosend;
public Dataclass(String jedan){
//super();
this.stringtosend = jedan;
}
}
// EDT constructor
JFrame frame;
public Gui1(){
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
initialize();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public void initialize() {
// JUST A FRAME WITH A PANEL AND A LABEL I WISH TO UPDATE
frame = new JFrame();
frame.setBounds(100, 100, 200, 90);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
frame.getContentPane().add(panel, BorderLayout.NORTH);
JLabel lblNovaOznaka = new JLabel();
panel.add(lblNovaOznaka);
frame.setVisible(true);
SwingWorker <Void, Dataclass> worker = new SwingWorker <Void, Dataclass>(){
#Override
protected Void doInBackground() throws Exception {
Logical logic = new Logical();
boolean looper = true;
String localstring;
while (looper == true){
logic.process();
localstring = logic.getRealtimestuff();
publish(new Dataclass(localstring));
}
return null;
}
#Override
protected void process(List<Dataclass> klasa) {
// do a lot of things in background and then pass a loto of arguments for gui updates
Dataclass xxx = klasa.get(getProgress());
lblNovaOznaka.setText(xxx.stringtosend);
}
};
worker.execute();
}
}

JButton stays pressed when focus stolen by JOptionPane

I am new to Swing and I have a situation. I am designing an application that renders the GUI components dynamically based on an xml file input(meta-data) . Now most of my JTextFields have InputVerifier set to them, for validation purpose. The input verifier pops up JOptionPane whenever there is an invalid input.
Now, if a user enter an invalid data and moves ahead and clicks a button on the Panel, then a dialog pops up and the user have to respond to it. but after that also the button does not paint to release state. It still looked like it is pressed but actually it is not. As the whole code is pretty messy, I am putting the problem scenario in the code below:-
What should I do so that the JButton looks unpressed? I would appreciate if the logic is also explained.
Thanks in advance.
package test;
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.InputVerifier;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
public class VerifierTest extends JFrame {
private static final long serialVersionUID = 1L;
public VerifierTest() {
JTextField tf;
tf = new JTextField("TextField1");
getContentPane().add(tf, BorderLayout.NORTH);
tf.setInputVerifier(new PassVerifier());
final JButton b = new JButton("Button");
b.setVerifyInputWhenFocusTarget(true);
getContentPane().add(b, BorderLayout.EAST);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (b.hasFocus())
System.out.println("Button clicked");
}
});
addWindowListener(new MyWAdapter());
}
public static void main(String[] args) {
Frame frame = new VerifierTest();
frame.setSize(400, 200);
frame.setVisible(true);
//frame.pack();
}
class MyWAdapter extends WindowAdapter {
public void windowClosing(WindowEvent event) {
System.exit(0);
}
}
class PassVerifier extends InputVerifier {
public boolean verify(JComponent input) {
JTextField tf = (JTextField) input;
String pass = tf.getText();
if (pass.equals("Manish"))
return true;
else {
String message = "illegal value: " + tf.getText();
JOptionPane.showMessageDialog(tf.getParent(), message,
"Illegal Value", JOptionPane.ERROR_MESSAGE);
return false;
}
}
}
}

The method verify is actually not a good place to open a JOptionPane.
There are several approaches you could consider to solve your problem:
You want this JOptionPane to appear everytime the textfield looses the focus and the input is incorrect: use a FocusListener on the JTextField and act upon appropriate events
You want this JOptionPane to appear everytime the buttons is pressed: use your ActionListener to do it if the input is incorrect.
Here is a small snippet of the latter option:
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.InputVerifier;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
public class VerifierTest extends JFrame {
private static final long serialVersionUID = 1L;
public VerifierTest() {
final JTextField tf = new JTextField("TextField1");
getContentPane().add(tf, BorderLayout.NORTH);
tf.setInputVerifier(new PassVerifier());
final JButton b = new JButton("Button");
b.setVerifyInputWhenFocusTarget(true);
getContentPane().add(b, BorderLayout.EAST);
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (!tf.getInputVerifier().verify(tf)) {
JOptionPane.showMessageDialog(tf.getParent(), "illegal value: " + tf.getText(), "Illegal Value",
JOptionPane.ERROR_MESSAGE);
}
if (b.hasFocus()) {
System.out.println("Button clicked");
}
}
});
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args) {
Frame frame = new VerifierTest();
frame.setSize(400, 200);
frame.setVisible(true);
}
class PassVerifier extends InputVerifier {
#Override
public boolean verify(JComponent input) {
final JTextField tf = (JTextField) input;
String pass = tf.getText();
return pass.equals("Manish");
}
}
}
Also consider setting the default close operation of the JFrame instead of adding a window listener (but it is a good approach to use a WindowListener if you want to pop up a dialog asking the user if he is sure he wants to exit your application).

I added a call to SwingUtilities to ensure that the GUI is on the event thread, and I removed your reference to Frame.
The GUI works for me on Windows XP.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.InputVerifier;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class VerifierTest implements Runnable {
private static final long serialVersionUID = 1L;
public VerifierTest() {
}
#Override
public void run() {
JFrame frame = new JFrame();
frame.setSize(400, 200);
JTextField tf;
tf = new JTextField("TextField1");
tf.setInputVerifier(new PassVerifier());
frame.getContentPane().add(tf, BorderLayout.NORTH);
final JButton b = new JButton("Button");
b.setVerifyInputWhenFocusTarget(true);
frame.getContentPane().add(b, BorderLayout.EAST);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (b.hasFocus())
System.out.println("Button clicked");
}
});
frame.addWindowListener(new MyWAdapter());
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new VerifierTest());
}
class MyWAdapter extends WindowAdapter {
#Override
public void windowClosing(WindowEvent event) {
System.exit(0);
}
}
class PassVerifier extends InputVerifier {
#Override
public boolean verify(JComponent input) {
JTextField tf = (JTextField) input;
String pass = tf.getText();
if (pass.equals("Manish"))
return true;
else {
String message = "illegal value: " + tf.getText();
JOptionPane.showMessageDialog(tf.getParent(), message,
"Illegal Value", JOptionPane.ERROR_MESSAGE);
return false;
}
}
}
}

I have added a new mouse listener to the button as below and its seems to be working fine for me now, but I am not sure if it is a good way of rectifying the buttons selection state.
package test;
import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.InputVerifier;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.plaf.basic.BasicButtonListener;
public class VerifierTest extends JFrame {
private static final long serialVersionUID = 1L;
public VerifierTest() {
JTextField tf;
tf = new JTextField("TextField1");
getContentPane().add(tf, BorderLayout.NORTH);
tf.setInputVerifier(new PassVerifier());
final JButton b = new JButton("Button");
b.setVerifyInputWhenFocusTarget(true);
getContentPane().add(b, BorderLayout.EAST);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (b.hasFocus())
System.out.println("Button clicked");
}
});
b.addMouseListener(new BasicButtonListener(b) {
#Override
public void mouseExited(MouseEvent e) {
((JButton)e.getSource()).getModel().setArmed(false);
((JButton)e.getSource()).getModel().setPressed(false);
}
});
addWindowListener(new MyWAdapter());
}
public static void main(String[] args) {
Frame frame = new VerifierTest();
frame.setSize(400, 200);
frame.setVisible(true);
// frame.pack();
}
class MyWAdapter extends WindowAdapter {
public void windowClosing(WindowEvent event) {
System.exit(0);
}
}
class PassVerifier extends InputVerifier {
public boolean verify(JComponent input) {
JTextField tf = (JTextField) input;
String pass = tf.getText();
if (pass.equals("Manish"))
return true;
else {
final String message = "illegal value: " + tf.getText();
JOptionPane.showMessageDialog(null, message,
"Illegal Value", JOptionPane.ERROR_MESSAGE);
return false;
}
}
}
}

First: all implementations of InputVerifier which open the dialog in verify() are invalid. They violated their contract, API doc:
This method should have no side effects.
with the "should" really meaning "must not". The correct place for side-effects is shouldYieldFocus.
Second: moving the side-effect (showing the message dialog) correctly into the shouldYieldFocus doesn't work as well ... due to a bug (THEY call it feature request ;-), that's older than a decade and in the top 10 RFEs
Being a hack-around a bug, #dareurdrem's mouseListener is as good as any workable hack can get :-)
Update
After playing a bit with different options to hack around the bug, here's another hack - it's as brittle as all hacks are (and doesn't survive a LAF toggle, has to be re-installed if dynamic toggling is required)
For hacking the mouse behaviour the basic approach is to hook into the listener installed by the ui:
find the original
implement a custom listener which delegates most events directly to the original
for pressed events request focus first: if yielded delegate to original, if not do nothing
The last bullet is slightly more involved because focus events can be asynchronous, so we have to invoke the check for being focused. Invoking, in turn, requires to send a release in case nobody objected.
Another quirk is the rootPane's pressed action (for its defaultButton): it's done without respecting any inputVerifiers by unconditionally calling doClick. That can be hacked by hooking into the action, following the same pattern as hooking into the mouseListener:
find the rootPane's pressed action
implement a custom action which checks for a potentially vetoing inputVerifier: delegate to the original if not, do nothing otherwise
The example modified along those lines:
public class VerifierTest implements Runnable {
private static final long serialVersionUID = 1L;
#Override
public void run() {
InteractiveTestCase.setLAF("Win");
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 200);
JTextField tf = new JTextField("TextField1");
tf.setInputVerifier(new PassVerifier());
frame.add(tf, BorderLayout.NORTH);
final JButton b = new JButton("Button");
frame.add(b);
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Button clicked");
}
});
// hook into the mouse listener
replaceBasicButtonListener(b);
frame.add(new JTextField("not validating, something else to focus"),
BorderLayout.SOUTH);
frame.getRootPane().setDefaultButton(b);
// hook into the default button action
Action pressDefault = frame.getRootPane().getActionMap().get("press");
frame.getRootPane().getActionMap().put("press", new DefaultButtonAction(pressDefault));
frame.setVisible(true);
}
protected void replaceBasicButtonListener(AbstractButton b) {
final BasicButtonListener original = getButtonListener(b);
if (original == null) return;
Hacker l = new Hacker(original);
b.removeMouseListener(original);
b.addMouseListener(l);
}
public static class Hacker implements MouseListener {
private BasicButtonListener original;
/**
* #param original the listener to delegate to.
*/
public Hacker(BasicButtonListener original) {
this.original = original;
}
/**
* Hook into the mousePressed: first request focus and
* check its success before handling it.
*/
#Override
public void mousePressed(final MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
if(e.getComponent().contains(e.getX(), e.getY())) {
// check if we can get the focus
e.getComponent().requestFocus();
invokeHandleEvent(e);
return;
}
}
original.mousePressed(e);
}
/**
* Handle the pressed only if we are focusOwner.
*/
protected void handlePressed(final MouseEvent e) {
if (!e.getComponent().hasFocus()) {
// something vetoed the focus transfer
// do nothing
return;
} else {
original.mousePressed(e);
// need a fake released now: the one from the
// original cycle might never has reached us
MouseEvent released = new MouseEvent(e.getComponent(), MouseEvent.MOUSE_RELEASED,
e.getWhen(), e.getModifiers(),
e.getX(), e.getY(), e.getClickCount(), e.isPopupTrigger()
);
original.mouseReleased(released);
}
}
/**
* focus requests might be handled
* asynchronously. So wrap the check
* wrap the block into an invokeLater.
*/
protected void invokeHandleEvent(final MouseEvent e) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
handlePressed(e);
}
});
}
#Override
public void mouseClicked(MouseEvent e) {
original.mouseClicked(e);
}
#Override
public void mouseReleased(MouseEvent e) {
original.mouseReleased(e);
}
#Override
public void mouseEntered(MouseEvent e) {
original.mouseEntered(e);
}
#Override
public void mouseExited(MouseEvent e) {
original.mouseExited(e);
}
}
public static class DefaultButtonAction extends AbstractAction {
private Action original;
/**
* #param original
*/
public DefaultButtonAction(Action original) {
this.original = original;
}
#Override
public void actionPerformed(ActionEvent e) {
JRootPane root = (JRootPane) e.getSource();
JButton owner = root.getDefaultButton();
if (owner != null && owner.getVerifyInputWhenFocusTarget()) {
Component c = KeyboardFocusManager
.getCurrentKeyboardFocusManager()
.getFocusOwner();
if (c instanceof JComponent && ((JComponent) c).getInputVerifier() != null) {
if (!((JComponent) c).getInputVerifier().shouldYieldFocus((JComponent) c)) return;
}
}
original.actionPerformed(e);
}
}
/**
* Returns the ButtonListener for the passed in Button, or null if one
* could not be found.
*/
private BasicButtonListener getButtonListener(AbstractButton b) {
MouseMotionListener[] listeners = b.getMouseMotionListeners();
if (listeners != null) {
for (MouseMotionListener listener : listeners) {
if (listener instanceof BasicButtonListener) {
return (BasicButtonListener) listener;
}
}
}
return null;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new VerifierTest());
}
public static class PassVerifier extends InputVerifier {
/**
* Decide whether or not the input is valid without
* side-effects.
*/
#Override
public boolean verify(JComponent input) {
final JTextField tf = (JTextField) input;
String pass = tf.getText();
if (pass.equals("Manish"))
return true;
return false;
}
/**
* Implemented to ask the user what to do if the input isn't valid.
* Note: not necessarily the best usability, it's mainly to
* demonstrate the different effects on not/agreeing with
* yielding focus transfer.
*/
#Override
public boolean shouldYieldFocus(final JComponent input) {
boolean valid = super.shouldYieldFocus(input);
if (!valid) {
String message = "illegal value: " + ((JTextField) input).getText();
int goAnyWay = JOptionPane.showConfirmDialog(input, "invalid value: " +
message + " - go ahead anyway?");
valid = goAnyWay == JOptionPane.OK_OPTION;
}
return valid;
}
}
}

Actually the real problem is in how the focus system and awt listeners interact. There are a few bugs declared in Java that the developers are going back and forth on who is responsible.
The mouse listener does : processMouseEvent and within that logic, the current FocusOwner is asked to yield Focus. it fails. But because half the event is processed already, the button becomes armed and the focus remains with the field.
I finally saw one developer comment: Don't let the listener proceed if the field is not allowed to lose focus.
For example:
Define a JTextfield with edits to only allow values < 100.
A message pops up when you lose focus.
I overrode my base JButton classes' processMouseEvent(MouseEvent e)
with code:
protected void processMouseEvent(MouseEvent e) {
if ( e.getComponent() != null && e.getComponent().isEnabled() ) { //should not be processing mouse events if it's disabled.
if (e.getID() == MouseEvent.MOUSE_RELEASED && e.getClickCount() == 1) {
// The mouse button is being released as per normal, and it's the first click. Process it as per normal.
super.processMouseEvent(e);
// If the release occured within the bounds of this component, we want to simulate a click as well
if (this.contains(e.getX(), e.getY())) {
super.processMouseEvent(new MouseEvent(e.getComponent(),
MouseEvent.MOUSE_CLICKED,
e.getWhen(),
e.getModifiers(),
e.getX(),
e.getY(),
e.getClickCount(),
e.isPopupTrigger(),
e.getButton()));
}
}
else if (e.getID() == MouseEvent.MOUSE_CLICKED && e.getClickCount() == 1) {
// Normal clicks are ignored to prevent duplicate events from normal, non-moved events
}
else if (e.getID() == MouseEvent.MOUSE_PRESSED && e.getComponent() != null && (e.getComponent().isFocusOwner() || e.getComponent().requestFocusInWindow())) {// if already focus owner process mouse event
super.processMouseEvent(e);
}
else {
// Otherwise, just process as per normal.
if (e.getID() != MouseEvent.MOUSE_PRESSED) {
super.processMouseEvent(e);
}
}
}
}
in the guts of this logic is the simple questions.
Button: Are you already focus owner.
if not: can you(Button) possibly GAIN focus ( remember - shouldYieldFocus() is called on the current focus holder inside the requestFocusInWindow() call and will return false ALWAYS if not valid )
This Also has the side affect of popping up your error dialog!
This logic Stops the Java libraries processMouseEvent logic from processing half an event while the Focus System stops it from completing.
Obviously you'll need this type of logic on all your different JComponents that perform an action on a click.

JInternalFrame selection

I have a JDesktopPane containing some JInternalFrames. I want some menus on the menubar to be activated only when one of the JInternalFrames is selected. I've tried using VetoableChangeListener, with the following code in it:
JInternalFrame selectedFrame = desk.getSelectedFrame();
if ((selectedFrame != null)) {
imageMenu.setEnabled(Boolean.TRUE);
} else {
imageMenu.setEnabled(Boolean.FALSE);
}
But the results are not what I expected - for example, the menu is enabled only the second time I add a frame. when I close all frames, it remains enabled.
How can I make this work?

you have to read basic tutorial about JInternalFrames with link to the InternalFrameListener,
but another and look like as better way is programatically to know those event in all cases and evety times is by adding PropertyChangeListener as shows examples Getting All Frames in a JDesktopPane Container, by adding PropertyChangeListener you can listeng for these events

Add an InternalFrameListener to each internal frame added to the desktop pane, and each time an event is triggered, execute the code you have shown in your question.
This code could be better written though:
setEnabled takes a primitive boolean as argument, not a java.lang.Boolean. Use true and false rather than Boolean.TRUE and Boolean.FALSE.
The expression (selectedFrame != null) evaluates as a boolean. Just write
imageMenu.setEnabled(selectedFrame != null);
instead of
if ((selectedFrame != null)) {
imageMenu.setEnabled(Boolean.TRUE);
} else {
imageMenu.setEnabled(Boolean.FALSE);
}

I would just create a custom event and fire it when a JInternalFrame gets focus (isActivated).
The menu items would listen for this event, intercept it and set their status enabled or disabled accordingly.
The advantage here is that you don't have to handle what menu items should be available for which types of internal frames, just fire the appropriate event. It'll make your life easier if you add more internal frames in the future.

This answer is based on the answer by #mKorbel. This example shows one of the ways to detect focus between internal frames as is demonstrated here:
package com.apexroot.sandbox;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JLabel;
/**
* author grants unlimited license to modify, reuse and redistribute. based on
* the suggestion by #mKorbel on stackoverflow at
* http://stackoverflow.com/questions/7219860/jinternalframe-selection
* please keep a URL to the original version in the source code.
* http://javajon.blogspot.com/2015/08/windowfocuslistener-for-jinternalframe.html
*
* #author Apexroot
*/
public class InternalFrameFocusListenerExample {
public static final String INTERNAL_FRAME_FOCUS_EVENT_PROPERTY = "selected";
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
final JFrame jFrame = new JFrame();
final JDesktopPane jDesktopPane = new JDesktopPane();
final JInternalFrame[] jInternalFrames = new FocusInternalFrame[3];
for (int i = 0; i < jInternalFrames.length; i++) {
jInternalFrames[i] = new FocusInternalFrame();
}
jFrame.dispose();
jFrame.setContentPane(jDesktopPane);
jDesktopPane.setPreferredSize(new Dimension(400, 200));
jFrame.pack();
jFrame.setVisible(true);
for (int i = 0; i < jInternalFrames.length; i++) {
jDesktopPane.add(jInternalFrames[i]);
jInternalFrames[i].setLocation(10 + 60 * i, 10 + 40 * i);
jInternalFrames[i].setVisible(true);
}
}
});
}
public static class FocusInternalFrame extends JInternalFrame {
public FocusInternalFrame() {
final JLabel jLabel = new JLabel("placeholder for pack();");
setContentPane(jLabel);
pack();
this.addPropertyChangeListener(
INTERNAL_FRAME_FOCUS_EVENT_PROPERTY,
new LabelFocusListener(jLabel));
}
}
private static class LabelFocusListener implements PropertyChangeListener {
private final JLabel jLabel;
public LabelFocusListener(JLabel jLabel) {
this.jLabel = jLabel;
}
#Override
public void propertyChange(PropertyChangeEvent evt) {
// please keep a URL to the original version in the source code.
// http://javajon.blogspot.com/2015/08/windowfocuslistener-for-jinternalframe.html
if (INTERNAL_FRAME_FOCUS_EVENT_PROPERTY.equals(
evt.getPropertyName())) {
final Object oldValue = evt.getOldValue();
final Object newValue = evt.getNewValue();
if (oldValue instanceof Boolean
&& newValue instanceof Boolean) {
boolean wasInFocus = (Boolean) oldValue;
boolean isInFocus = (Boolean) newValue;
if (isInFocus && !wasInFocus) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
// focus gained
jLabel.setText("focus gained");
}
});
} else if (wasInFocus && !isInFocus) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
// focus lost
jLabel.setText("focus lost");
}
});
}
}
}
}
}
}