We Keep Coding

How to refresh/reload an image in Swing GUI as the real image file changes?

I am trying to implement Remote FrameBuffer Protocol using Java socket programming.
I have a server side program that takes screenshot of the entire screen using robot and store it in BufferedImage .Then I converted it into a byte array and sending it to the client .
Objective :
To display the entire screen of the server side machine in a Swing GUI of the client side.
Problem i am facing :
i am able to send the image in bytes from server and receive it from the server by the client (client.java) and convert it into a jpg image (output.jpg) using ImageIO and put that image in a Swing frame.
But i am able to see the first image in the Swing and whenever the image gets updated ,the image in the Swing is not updating or refreshing .
What I want :
I want the image to refresh and show updated image every time the server sends the image data .
client.java
package remoteclient;
import java.lang.*;
import javax.imageio.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import java.net.*;
import java.io.*;
public class client {
public static void main(String args[])throws Exception{
Socket s=new Socket("localhost",5900);
DataInputStream din=new DataInputStream(s.getInputStream());
DataOutputStream dout=new DataOutputStream(s.getOutputStream());
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
int width=0,height=0;
try {
width = din.readInt(); //getting width and height from server thru socket.
height = din.readInt();
} catch (Exception e) {
e.printStackTrace();
}
JFrame f = new JFrame("Client");
JLabel label = new JLabel();
f.setSize(width, height);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
boolean continueLoop = true;
while(continueLoop)
{
try {
int len = din.readInt();
byte[] imageInByte = new byte[len];
System.out.println(len);
din.readFully(imageInByte);
System.out.println(imageInByte);
ByteArrayInputStream bis = new ByteArrayInputStream(imageInByte);
BufferedImage bImage2 = ImageIO.read(bis);
// Image im1 = bImage2.getScaledInstance(width,height, Image.SCALE_SMOOTH);
ImageIO.write(bImage2, "jpg", new File("output.jpg") );
bImage2 = ImageIO.read(new File("output.jpg"));
label.setIcon(new ImageIcon(im1));
ImageIcon icon = new ImageIcon(bImage2);
icon.getImage().flush();
label.setIcon( icon );
f.getContentPane().add(label, BorderLayout.CENTER);
f.pack();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
What I want :
I want the image to refresh and show updated image every time the server sends the image data .

Updated code with comments about demo code that should be removed from your working code:
Here's an example, using default UIManager icons, and SwingWorker, as noted in the comments to the original posting. You would instead use images from your server connection.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.SwingWorker;
import javax.swing.UIManager;
public class SwingLabelWithUpdatedImage {
public static void main(String args[]) throws Exception {
final JLabel label = new JLabel("", SwingConstants.CENTER);
final JFrame frame = new JFrame("Client");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(label, BorderLayout.CENTER);
final Dimension preferredSize = new Dimension(200, 100);
frame.setPreferredSize(preferredSize);
frame.setVisible(true);
frame.pack();
final ImageUpdateWorker task = new ImageUpdateWorker(label);
task.execute();
}
public static class ImageUpdateWorker extends SwingWorker<Void, IconInfo> {
// iconInfoList is not need in your code. It's here so I can
// supply a dummy set of icons to demonstrate UI updates.
final List<IconInfo> iconInfoList;
private JLabel label;
ImageUpdateWorker(JLabel label) {
this.label = label;
// Delete this in your code
this.iconInfoList = initIconInfoList();
}
#Override
public Void doInBackground() {
boolean isTrue = true;
while (isTrue) {
// Put your socket code to read the next icon from a server.
// You don't need to do the ImageIO.write(), ImageIO.read() dance,
// unless you must save the icon to disk. In that case, you don't need
// to read it back in.
// Here, I just rotate the iconInfoList to make it
// appear as though a new icon was received.
// Your code will not have any need to do this.
Collections.rotate(iconInfoList, -1);
// Just publish the icon you create from the image
// you receive from your remote server.
publish(iconInfoList.get(0));
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return null;
}
#Override
protected void process(List<IconInfo> icons) {
// You might check for an empty list.
// #kleopatra's suggestion to get the last icon is correct.
// See https://docs.oracle.com/javase/tutorial/uiswing/concurrency/interim.html
IconInfo iconInfo = icons.get(icons.size() - 1);
label.setIcon(iconInfo.icon);
// Your code will not do this
label.setText(iconInfo.name);
// You can get the icon dimensions just from the icon,
// so you don't really need the IconInfo class.
label.setSize(iconInfo.dimension);
}
/** Demo code only. It doesn't belong in your working code.
*/
protected List<IconInfo> initIconInfoList() {
// Just a quick way to get some icons; don't need to
// fetch from a server just to demonstrate how to
// refresh the UI.
List<IconInfo> iconInfoList = UIManager.getDefaults().keySet().stream()
.filter(this::isIconKey)
.map(IconInfo::new)
.filter(iconInfo -> iconInfo.icon != null)
.collect(Collectors.toList());
return iconInfoList;
}
/** Demo code only. It doesn't belong in your working code.
*/
protected boolean isIconKey(Object key) {
return String.class.isAssignableFrom(key.getClass())
&& ((String) key).toLowerCase().contains("icon");
}
}
/** This is just a convenience to convey
* the icon and its UIManager key (i.e., name).
* Your remote server doesn't supply a name,
* so you don't really need this class.
* It's just to make the demo more expressive.
*/
public static class IconInfo {
final private String name;
final private Icon icon;
final private Dimension dimension;
IconInfo(Object name) {
this.name = name.toString();
icon = UIManager.getIcon(name);
dimension = icon == null
? new Dimension(32, 32)
: new Dimension(icon.getIconWidth(), icon.getIconHeight());
}
}
}

How to synchronize ImageIcon in ImageLoader

I recently started to use multithreading in Java and I've run into a problem I assume is due to missing synchronization.
This is a ImageLoader I wrote:
package util;
import javax.swing.ImageIcon;
public class ImageLoader extends Thread {
private String file;
private ImageIcon icon;
public ImageLoader(String file) {
this.file = file;
}
#Override
public void run() {
ImageIcon icon = new ImageIcon(this.file);
this.icon = icon;
super.run();
}
public synchronized ImageIcon returnIcon() {
return this.icon;
}
}
I use this ImageLoader in my GUI-Class:
package gui;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import util.ImageLoader;
public class HauptGui extends JComponent {
public HauptGui() {
initUI();
}
private void initUI() {
int bilderAnzahl = 3;
this.setLayout(new GridLayout(1, 1));
JPanel bilderPanel = new JPanel(new GridLayout(bilderAnzahl, 1));
for (int i = 0; i < bilderAnzahl; i++) {
JLabel jbl = new JLabel();
ImageLoader loader = new ImageLoader("./Picture.jpg");
loader.start();
jbl.setIcon(loader.returnIcon());
jbl.setBorder(BorderFactory.createEtchedBorder());
jbl.setPreferredSize(new Dimension(200, 50));
bilderPanel.add(jbl);
}
JScrollPane scrPn = new JScrollPane(bilderPanel);
this.add(scrPn);
}
}
The Problem is that the returnIcon-Method of the ImageLoader gets called before the Thread calls the run-Method, therefore the ImageIcon is still null.
How do I synchronize this?

No, your problem has nothing to do with synchronization and all to do with simply requesting the image object before it has been created. The solution is to get the image object in a call-back, after it has completed its loading. A SwingWorker would work well in this situation, where you get the image object from the SwingWorker in the worker's done method by calling .get() on it, or you could use a PropertyChangeListener for your callback. See Lesson: Concurrency in Swing for the details on how to use SwingWorkers.
For example (code not tested)
public class ImageLoader2 extends SwingWorker<BufferedImage, Void> {
private String path = ""; /// String to resource path
public BufferedImage doInBackground() throws Exception {
return ImageIO.read(ImageLoader2.class.getResource(path));
}
}
and then run it like:
ImageLoader2 loader = new ImageLoader2();
loader.addPropertyChangeListener(pce -> {
if (evt.getNewValue() == SwingWorker.StateValue.DONE) {
try {
BufferedImage img = loader.get();
ImageIcon icon = new ImageIcon(img);
// use icon here...
} catch catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
// handle exception here
}
}
});
loader.execute();
Side notes
you should almost never extend Thread.
Don't get the image as a File as you are doing but rather get it as a resource and use ImageIO.read(...) to do this
The resource path is relative to the class-path, not to the user's directory, and so it will likely be different from the path you use to get the image as a file.

Showing PDF in JScrollPane with Aspose

I'm trying to use Aspose PDF Kit (4.7.0) to display a PDF in JScrollPane as documented in their javadoc, using PdfViewer.showPdf() method.
The result is that I can only see 1 page of my -very simple- document and it is not being correctly rendered:
Here is my code below:
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import com.aspose.pdf.kit.PdfViewer;
public class SimplePdfViewer extends JFrame
{
/**
* serialVersionUID
*/
private static final long serialVersionUID = -494213537688110764L;
public SimplePdfViewer()
{
try
{
// Aspose license initialisation
Aspose.init();
PdfViewer pdfviewer = new PdfViewer();
pdfviewer.openPdfFile("src/main/resources/10 pages.pdf");
//decode the pdf page, I also tried pdfViewer.decodeAllPages() and only the last one is displayed.
pdfviewer.decodePage(1);
pdfviewer.setPdfPageParameters(1, 1);
JScrollPane displayScrollPane = pdfviewer.showPdf();
getContentPane().add(displayScrollPane, BorderLayout.CENTER);
}
catch (Exception e)
{
// TODO Auto-generated catch block
e.printStackTrace();
getContentPane().add(new JLabel(e.getMessage()));
}
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
public static void main(String[] args)
{
new SimplePdfViewer();
}
}
Am I missing something ?

Ok, be aware that it is actually not implemented :
http://www.aspose.com/community/forums/permalink/419184/419184/showthread.aspx#419184

JEditorPane linewrap in Java7

First of all I hope it's not a problem I started a new topic. Tbh I don't have a clue how to ask a question based on an already answered one, so I made this.
I'm pretty new with Java and my problem is the following. I'm writing a little chat program and I'm using a JEditorPane with an HTMLEditorKit to display text in different colors, to display smileys, and display hyperlinks.
My problem is, and after some research I found out the problem might be due to Java7, I can't get the linewrap working properly. I want the text to word wrap and to wrap in the middle of Strings exceeding the width of the component.
The word wrap works fine, but if someone types in a pretty long string the JEditorPane gets expanded and you need to resize the frame to get everything on screen, which is what I do not want to happen.
I've tried a few fixes for this problem, but they only allow letter wrap such that word wrap no longer works. Beside that, I want the user to be able to wrap his text by hitting Enter. For that I'm adding \n to the text and with the fixes this will no longer affect the result and everything's going to be displayed in one line.
I'm feeling like I've spent years in the web to find a solution but unitl now nothing worked for my case, especially since it appeared to be the same fix all the time. I hope you guys can help me.
This means in summary:
What I have:
Line wraps word in case of long strings separated by spaces
if you use Windows and your input contains line wraps created by hitting enter, they will also wrap
If you type in a very long string without spaces, the panel gets expanded and you need to resize the frame
HTML formatting allows me to display different colors as well as hyperlinks and emoticons
What I need:
Word wrap behaviour like it is at the moment in case it is possible but letter wrap ONLY in case of long strings not separated by spaces to prevent the panel from expanding.
Manually added line wraps made by hitting ENTER in the input area or if I copy an pre formatted text into the input panel
HTML formatting like I have already
What I've tried and what didn't help:
jtextpane doesn't wrap text and
JTextPane is not wrapping text
Here is some code to try it yourself. In the bottom left is an input area to type in some text. You can also add line wraps by hitting enter. After clicking on the button you will see the text in the area above.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.border.TitledBorder;
import javax.swing.text.BadLocationException;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.StyleSheet;
#SuppressWarnings("serial")
public class LineWrapTest extends JFrame implements ActionListener, KeyListener {
private JButton btnSend;
private JTextArea textAreaIn;
private JEditorPane textAreaOut;
private HTMLEditorKit kit;
private HTMLDocument doc;
public LineWrapTest() {
this.setSize(600, 500);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setTitle("Linewrap Test");
}
/**
* Not important for problem
*/
public void paintScreen() {
this.setLayout(new BorderLayout());
this.add(this.getPanelOut(), BorderLayout.CENTER);
this.add(this.getPanelIn(), BorderLayout.SOUTH);
this.textAreaIn.requestFocusInWindow();
this.setVisible(true);
}
/**
* Not important for problem
*
* #return panelOut
*/
private JPanel getPanelOut() {
JPanel panelOut = new JPanel();
panelOut.setLayout(new BorderLayout());
this.textAreaOut = new JEditorPane();
this.textAreaOut.setEditable(false);
this.textAreaOut.setContentType("text/html");
this.kit = new HTMLEditorKit();
this.doc = new HTMLDocument();
StyleSheet styleSheet = this.kit.getStyleSheet();
this.kit.setStyleSheet(styleSheet);
this.textAreaOut.setEditorKit(this.kit);
this.textAreaOut.setDocument(this.doc);
TitledBorder border = BorderFactory.createTitledBorder("Output");
border.setTitleJustification(TitledBorder.CENTER);
panelOut.setBorder(border);
panelOut.add(this.textAreaOut);
return panelOut;
}
/**
* Not important for problem
*
* #return panelIn
*/
private JPanel getPanelIn() {
JPanel panelIn = new JPanel();
panelIn.setLayout(new BorderLayout());
this.textAreaIn = new JTextArea();
this.textAreaIn.setLineWrap(true);
this.textAreaIn.setWrapStyleWord(true);
TitledBorder border = BorderFactory.createTitledBorder("Input");
border.setTitleJustification(TitledBorder.CENTER);
panelIn.setBorder(border);
panelIn.add(this.getBtnSend(), BorderLayout.EAST);
panelIn.add(this.textAreaIn, BorderLayout.CENTER);
return panelIn;
}
/**
* Not important for problem
*
* #return btnSend
*/
private JButton getBtnSend() {
this.btnSend = new JButton("Send");
this.btnSend.addActionListener(this);
return this.btnSend;
}
private void append(String text) {
try {
this.kit.insertHTML(this.doc, this.doc.getLength(), text, 0, 0, null);
} catch (BadLocationException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private String getHTMLText() {
String txtIn = this.textAreaIn.getText().trim().replaceAll(SEPARATOR, "<br/>");
StringBuffer htmlBuilder = new StringBuffer();
htmlBuilder.append("<HTML>");
htmlBuilder.append(txtIn);
htmlBuilder.append("</HTML>");
return htmlBuilder.toString();
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == this.btnSend) {
this.append(this.getHTMLText());
this.textAreaIn.setText("");
this.textAreaIn.requestFocusInWindow();
}
}
public static void main(String[] args) {
LineWrapTest test = new LineWrapTest();
test.paintScreen();
}
#Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER)
if (!this.textAreaIn.getText().trim().isEmpty())
this.textAreaIn.setText(this.textAreaIn.getText() + SEPARATOR);
}
#Override
public void keyReleased(KeyEvent e) {
}
#Override
public void keyTyped(KeyEvent e) {
}
}
UPDATE:
base on some parts of http://java-sl.com/tip_java7_text_wrapping_bug_fix.html
Somehow I figured it out to step a bit closer to my goal. I've tried to combine the fix for an HTMLEditorKit with an StlyedEditorKit Fix. But I have to be honest, I don't have any clue what I actually did there :( The sad thing is, the manual line wraping does no longer work with this as a replacement of the HTMLEditorKit.
Maybe you can use this as a base for some better implementation.
To use it in my example just create a new class in the project with the CustomEditorKit and replace the HTMLEditorKit in the example with this CustomEditorKit.
You will notice that word and letter wrapping works now, but if you hit ENTER to get your own line wrap this change will no longer appear in the output-panel and everything will be displayed in one line.
Another strange problem of it is, that if you resize the frame the lines will sometimes lay on each other.
import javax.swing.SizeRequirements;
import javax.swing.text.Element;
import javax.swing.text.View;
import javax.swing.text.ViewFactory;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.InlineView;
import javax.swing.text.html.ParagraphView;
#SuppressWarnings("serial")
public class CustomEditorKit extends HTMLEditorKit {
#Override
public ViewFactory getViewFactory() {
return new HTMLFactory() {
#Override
public View create(Element e) {
View v = super.create(e);
if (v instanceof InlineView) {
return new InlineView(e) {
#Override
public int getBreakWeight(int axis, float pos, float len) {
return GoodBreakWeight;
}
#Override
public View breakView(int axis, int p0, float pos, float len) {
if (axis == View.X_AXIS) {
this.checkPainter();
this.removeUpdate(null, null, null);
}
return super.breakView(axis, p0, pos, len);
}
};
}
else if (v instanceof ParagraphView) {
return new ParagraphView(e) {
#Override
protected SizeRequirements calculateMinorAxisRequirements(int axis, SizeRequirements r) {
if (r == null) {
r = new SizeRequirements();
}
float pref = this.layoutPool.getPreferredSpan(axis);
float min = this.layoutPool.getMinimumSpan(axis);
// Don't include insets, Box.getXXXSpan will include them.
r.minimum = (int) min;
r.preferred = Math.max(r.minimum, (int) pref);
r.maximum = Integer.MAX_VALUE;
r.alignment = 0.5f;
return r;
}
};
}
return v;
}
};
}
}

OK! So, I finally got everything you were having problems with working. It took some research and a lot of trial and error, but here it is:
Here is what I did:
Put the JEditorPane in a JScrollPane so you can scroll up and down as the message gets bigger
Added a custom word wrap. The custom word wrap will wrap words and long words in the desired location of the word. You were right, this is a bug with the current version of Java. http://bugs.sun.com/view_bug.do?bug_id=7125737
Added the ability for the user to wrap to a new line by hitting Enter. This interfered with the custom word wrap though, so you may not like how I achieved this. In the code example I suggest other options.
Preserved your HTMLDocument abilities. I was tempted to not do this, but I found work arounds so that it could be preserved.
The application still uses a JEditorPane, but you could switch it to a JTextPane if you want. I tried both and they were both functional.
So here is the code. It's a bit long and you may wish to change it based on your preferences. I commented where I made changes and tried to explain them.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;
import javax.swing.SizeRequirements;
import javax.swing.border.TitledBorder;
import javax.swing.text.*;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.InlineView;
import javax.swing.text.html.StyleSheet;
#SuppressWarnings("serial")
public class LineWrapTest extends JFrame implements ActionListener, KeyListener {
//This is the separator.
private String SEPARATOR = System.getProperty("line.separator");
private JButton btnSend;
private JTextArea textAreaIn;
private JEditorPane textAreaOut;
private JScrollPane outputScrollPane;
private HTMLEditorKit kit;
private HTMLDocument doc;
public LineWrapTest() {
this.setSize(600, 500);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setTitle("Linewrap Test");
}
/**
* Not important for problem
*/
public void paintScreen() {
this.setLayout(new BorderLayout());
this.add(this.getPanelOut(), BorderLayout.CENTER);
this.add(this.getPanelIn(), BorderLayout.SOUTH);
this.textAreaIn.requestFocusInWindow();
this.setVisible(true);
}
/**
* Not important for problem
*
* #return panelOut
*/
private JPanel getPanelOut() {
JPanel panelOut = new JPanel();
panelOut.setLayout(new BorderLayout());
this.textAreaOut = new JEditorPane();
this.textAreaOut.setEditable(false);
this.textAreaOut.setContentType("text/html");
//I added this scroll pane.
this.outputScrollPane = new JScrollPane(this.textAreaOut);
/*
* This is a whole whack of code. It's a combination of two sources.
* It achieves the wrapping you desire: by word and longgg strings
* It is a custom addition to HTMLEditorKit
*/
this.kit = new HTMLEditorKit(){
#Override
public ViewFactory getViewFactory(){
return new HTMLFactory(){
public View create(Element e){
View v = super.create(e);
if(v instanceof InlineView){
return new InlineView(e){
public int getBreakWeight(int axis, float pos, float len) {
//return GoodBreakWeight;
if (axis == View.X_AXIS) {
checkPainter();
int p0 = getStartOffset();
int p1 = getGlyphPainter().getBoundedPosition(this, p0, pos, len);
if (p1 == p0) {
// can't even fit a single character
return View.BadBreakWeight;
}
try {
//if the view contains line break char return forced break
if (getDocument().getText(p0, p1 - p0).indexOf(SEPARATOR) >= 0) {
return View.ForcedBreakWeight;
}
}
catch (BadLocationException ex) {
//should never happen
}
}
return super.getBreakWeight(axis, pos, len);
}
public View breakView(int axis, int p0, float pos, float len) {
if (axis == View.X_AXIS) {
checkPainter();
int p1 = getGlyphPainter().getBoundedPosition(this, p0, pos, len);
try {
//if the view contains line break char break the view
int index = getDocument().getText(p0, p1 - p0).indexOf(SEPARATOR);
if (index >= 0) {
GlyphView v = (GlyphView) createFragment(p0, p0 + index + 1);
return v;
}
}
catch (BadLocationException ex) {
//should never happen
}
}
return super.breakView(axis, p0, pos, len);
}
};
}
else if (v instanceof ParagraphView) {
return new ParagraphView(e) {
protected SizeRequirements calculateMinorAxisRequirements(int axis, SizeRequirements r) {
if (r == null) {
r = new SizeRequirements();
}
float pref = layoutPool.getPreferredSpan(axis);
float min = layoutPool.getMinimumSpan(axis);
// Don't include insets, Box.getXXXSpan will include them.
r.minimum = (int)min;
r.preferred = Math.max(r.minimum, (int) pref);
r.maximum = Integer.MAX_VALUE;
r.alignment = 0.5f;
return r;
}
};
}
return v;
}
};
}
};
this.doc = new HTMLDocument();
StyleSheet styleSheet = this.kit.getStyleSheet();
this.kit.setStyleSheet(styleSheet);
this.textAreaOut.setEditorKit(this.kit);
this.textAreaOut.setDocument(this.doc);
TitledBorder border = BorderFactory.createTitledBorder("Output");
border.setTitleJustification(TitledBorder.CENTER);
panelOut.setBorder(border);
//I changed this to add the scrollpane, which now contains
//the JEditorPane
panelOut.add(this.outputScrollPane);
return panelOut;
}
/**
* Not important for problem
*
* #return panelIn
*/
private JPanel getPanelIn() {
JPanel panelIn = new JPanel();
panelIn.setLayout(new BorderLayout());
this.textAreaIn = new JTextArea();
this.textAreaIn.setLineWrap(true);
this.textAreaIn.setWrapStyleWord(true);
//This disables enter from going to a new line. Your key listener does that.
this.textAreaIn.getInputMap().put(KeyStroke.getKeyStroke("ENTER"), "none");
//For the key listener to work, it needs to be added to the component
this.textAreaIn.addKeyListener(this);
TitledBorder border = BorderFactory.createTitledBorder("Input");
border.setTitleJustification(TitledBorder.CENTER);
panelIn.setBorder(border);
panelIn.add(this.getBtnSend(), BorderLayout.EAST);
panelIn.add(this.textAreaIn, BorderLayout.CENTER);
return panelIn;
}
/**
* Not important for problem
*
* #return btnSend
*/
private JButton getBtnSend() {
this.btnSend = new JButton("Send");
this.btnSend.addActionListener(this);
return this.btnSend;
}
private void append(String text) {
try {
this.kit.insertHTML(this.doc, this.doc.getLength(), text, 0, 0, null);
} catch (BadLocationException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private String getHTMLText() {
//I tried to find a work around for this but I couldn't. It could be done
//by manipulating the HTMLDocument but it's beyond me. Notice I changed
//<br/> to <p/>. For some reason, <br/> no longer went to the next line
//when I added the custom wrap. <p/> seems to work though.
String txtIn = this.textAreaIn.getText().trim().replaceAll(SEPARATOR, "<p/>");
//My IDE recommends you use StringBuilder instead, that's up to you.
//I am not sure what the difference would be.
StringBuffer htmlBuilder = new StringBuffer();
htmlBuilder.append("<HTML>");
htmlBuilder.append(txtIn);
htmlBuilder.append("</HTML>");
return htmlBuilder.toString();
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == this.btnSend) {
this.append(this.getHTMLText());
this.textAreaIn.setText("");
this.textAreaIn.requestFocusInWindow();
}
}
public static void main(String[] args) {
LineWrapTest test = new LineWrapTest();
test.paintScreen();
}
#Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER){
if (!this.textAreaIn.getText().trim().isEmpty()) {
//I made this work by defining the SEPARATOR.
//You could use append(Separator) instead if you want.
this.textAreaIn.setText(this.textAreaIn.getText() + SEPARATOR);
}
}
}
#Override
public void keyReleased(KeyEvent e) {
}
#Override
public void keyTyped(KeyEvent e) {
}
}
Here are (most of) the links that I used to solve this problem:
Enabling word wrap in a JTextPane with HTMLDocument
Custom wrap is a combination of these two:
http://java-sl.com/tip_html_letter_wrap.html
http://java-sl.com/wrap.html
Deleting the keybind for JTextArea:
http://docs.oracle.com/javase/tutorial/uiswing/misc/keybinding.html
If you have any questions whatsoever, just comment below. I will answer them. I sincerely hope this solves your problems

A deadly better solution I found :
The <br> is correctly handled by the HTMLEditorKit, but the Patrick Sebastien's post mentionned that it won't. It's because its ViewFactory threat all InlineView object as wrappable, but the BRView is also an InlineView. See my solution below:
class WrapColumnFactory extends HTMLEditorKit.HTMLFactory {
#Override
public View create(Element elem) {
View v = super.create(elem);
if (v instanceof LabelView) {
// the javax.swing.text.html.BRView (representing <br> tag) is a LabelView but must not be handled
// by a WrapLabelView. As BRView is private, check the html tag from elem attribute
Object o = elem.getAttributes().getAttribute(StyleConstants.NameAttribute);
if ((o instanceof HTML.Tag) && o == HTML.Tag.BR) {
return v;
}
return new WrapLabelView(elem);
}
return v;
}
}
class WrapLabelView extends LabelView {
public WrapLabelView(Element elem) {
super(elem);
}
#Override
public float getMinimumSpan(int axis) {
switch (axis) {
case View.X_AXIS:
return 0;
case View.Y_AXIS:
return super.getMinimumSpan(axis);
default:
throw new IllegalArgumentException("Invalid axis: " + axis);
}
}
}

JOptionPane.showMessageDialog() shows but without any message?

In the following code, I call JOptionPane.showMessageDialog, inside a try/catch block. But when the error is caught, my JOptionPane is visible but without any message !!! Does someone knows why and how I can correct the problem ?
Regards
MyBoardJPannel.java
package experimentations.gui;
import java.awt.Graphics;
import java.awt.Image;
import java.io.InputStream;
import javax.imageio.ImageIO;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class MyBoardPannel extends JPanel {
#Override
public void paint(Graphics grahics) {
if (imageToShow == null)
imageToShow = loadImage("sampleImage");
}
/**
* In fact, there are not any image in project => will go to catch clause.
* #param imageName
*/
private void loadImage(String imageName) {
InputStream imageStream = getClass().getResourceAsStream("/"+imageName+".png");
try {
imageToShow = ImageIO.read(imageStream);
}
catch (Exception e) {
String errorMessage = "Failed to load image "+imageName;
System.err.println(errorMessage);
JOptionPane.showMessageDialog(this, errorMessage,
"Image loading error", JOptionPane.ERROR_MESSAGE);
imageToShow = null;
System.exit(1);
}
}
private Image imageToShow;
}
JOptionPaneErrorShowing.java
package experimentations.gui;
import javax.swing.JFrame;
public class JOptionPaneErrorShowing extends JFrame {
public JOptionPaneErrorShowing(){
setTitle("JOptionPane experimentation");
setSize(300, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
add(new MyBoardPannel());
}
/**
* #param args
*/
public static void main(String[] args) {
new JOptionPaneErrorShowing().setVisible(true);
}
}

It's likely a Swing concurrency issue. But more importantly, you should never load an image from within a paint or paintComponent method, ever. Read it in the constructor or elsewhere but paint/paintComponent need to be lean and blazingly fast.
To solve your issue, consider reading in the image in SwingWorker object. If you call a JOptionPane from within the SwingWorker's doInBackground method though, be sure to call it on the Swing event thread, the EDT, using SwingUtilities.invokeLater(Runnable).
Also, you will hardly ever want to draw in a JPanel's paint method unless you are taking care of painting borders and children. Instead paint in a paintComponent method, and don't forget to call the super.paintComponent(g) method in that paintComponent override. You'll want to read the Swing graphics tutorials as this is all spelled out there.
For example:
import java.awt.Graphics;
import java.awt.Image;
import java.io.InputStream;
import java.util.concurrent.ExecutionException;
import javax.imageio.ImageIO;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
public class MyBoardPannel extends JPanel {
protected static final String SAMPLE_IMAGE = "sampleImage";
Image imageToShow = null;
public MyBoardPannel() {
SwingWorker<Image, Void> mySW = new SwingWorker<Image, Void>() {
#Override
protected Image doInBackground() throws Exception {
return loadImage(SAMPLE_IMAGE);
}
#Override
protected void done() {
try {
imageToShow = get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
};
mySW.execute();
}
#Override
public void paintComponent(Graphics grahics) {
super.paintComponent(grahics);
if (imageToShow != null) {
grahics.drawImage(imageToShow, 0, 0, null);
}
}
private Image loadImage(String imageName) {
InputStream imageStream = getClass().getResourceAsStream(
"/" + imageName + ".png");
try {
return ImageIO.read(imageStream);
} catch (Exception e) {
final String errorMessage = "Failed to load image " + imageName;
System.err.println(errorMessage);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JOptionPane.showMessageDialog(MyBoardPannel.this, errorMessage,
"Image loading error", JOptionPane.ERROR_MESSAGE);
System.exit(1);
}
});
}
return null;
}
}

I don't really know, but maybe your panel you use as parent of the JOptionPane (by passing this) is invisible or there is something else wrong. Try adding pack(); at the end of your JOptionPaneErrorShowing constructor.
What I know is that I had this problem when I was using an old Ubuntu and old Nvidia driver for my GPU, when the desktop effects were turned on (the Compiz Fusion of today. I don't know if it was already called Compiz, that long ago).
Aha! I found it, you are displaying the error inside the repaint method. Never do that! Load your image inside the constructor of the MyBoardPanel class and show error messages over there.