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);
}
}
}
Related
In my application I use a JTextPane embedded in a JScrollPane to display text which is formatted using HTML tags. At first I used JTextArea but then switched to JTextPane to be able to use HTML and colors. Then I needed the JTextPane to support letter based wrapping instead of just the default wrapping by white space. In other words if the content is too long it should be wrapped and the horizontal scroll bar of the JScrollPane should not be visible.
Therefore, I found a solution in this answer that works perfectly: https://stackoverflow.com/a/6330483/3871673.
It uses a custom HTMLEditorKit for the JTextPane.
But with this solution the JTextPane ignores any line breaks with the HTML tag <br>. I have to admit I don't really know how the code in the solution works. It would be great if someone could find out how to get the HTML new line <br> tag working with this solution.
Here is a minimal, complete & verifiable example:
import javax.swing.*;
import javax.swing.text.Element;
import javax.swing.text.ParagraphView;
import javax.swing.text.View;
import javax.swing.text.ViewFactory;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.InlineView;
import java.awt.*;
public class JTextPaneTest extends JFrame {
public static void main(String[] args) {
new JTextPaneTest();
}
public JTextPaneTest(){
setLayout(new BorderLayout());
JTextPane textPane = new JTextPane();
textPane.setContentType("text/html");
textPane.setEditorKit(new HTMLEditorKitWrapSupport()); // makes JTextPane ignore <br> tag
// example 1 (JTextPane ignores <br> tag when using the custom HTMLEditorKit)
textPane.setText("<html><body style='font-size:22pt'> <p>Line 1 <br> Line 2</p> </body></html>");
// example 2 (the text should be wrapped and the JScrollPane's horizontal bar should not be visible)
//textPane.setText("<html><body style='font-size:25pt'> <p>LONGWORDWITHOUTSPACES_LONGWORDWITHOUTSPACES_LONGWORDWITHOUTSPACES_LONGWORDWITHOUTSPACES_LONGWORDWITHOUTSPACES_</p> </body></html>");
JScrollPane scrollPane = new JScrollPane(textPane);
add(scrollPane, BorderLayout.CENTER);
setSize(new Dimension(500, 500));
setVisible(true);
}
class HTMLEditorKitWrapSupport extends HTMLEditorKit {
#Override
public ViewFactory getViewFactory() {
return new HTMLEditorKit.HTMLFactory() {
public View create(Element element) {
View view = super.create(element);
if (view instanceof InlineView) {
return new InlineView(element) {
#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) {
checkPainter();
int p1 = getGlyphPainter().getBoundedPosition(this, p0, pos, len);
if (p0 == getStartOffset() && p1 == getEndOffset()) {
return this;
}
return createFragment(p0, p1);
}
return this;
}
};
} else if (view instanceof ParagraphView) {
return new ParagraphView(element) {
protected SizeRequirements calculateMinorAxisRequirements(int axis, SizeRequirements sizeRequirements) {
if (sizeRequirements == null) {
sizeRequirements = new SizeRequirements();
}
float pref = layoutPool.getPreferredSpan(axis);
float min = layoutPool.getMinimumSpan(axis);
// Don't include insets, Box.getXXXSpan will include them.
sizeRequirements.minimum = (int) min;
sizeRequirements.preferred = Math.max(sizeRequirements.minimum, (int) pref);
sizeRequirements.maximum = Integer.MAX_VALUE;
sizeRequirements.alignment = 0.5f;
return sizeRequirements;
}
};
}
return view;
}
};
}
}
}
When a JEditorPane backed by an HTMLEditorKit contains a <br> tag followed by an empty line, that line is not rendered correctly and the caret is not handled correctly. Consider this sample code:
import java.awt.*;
import java.io.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.*;
public class HTMLEditorTest {
public static void main(String[] args) throws IOException, BadLocationException {
JFrame frame = new JFrame();
Reader stringReader = new StringReader("test<br><p>a");
HTMLEditorKit htmlKit = new HTMLEditorKit();
HTMLDocument htmlDoc = (HTMLDocument) htmlKit.createDefaultDocument();
htmlKit.read(stringReader, htmlDoc, 0);
JEditorPane editorPane = new JEditorPane();
editorPane.setEditorKit(htmlKit);
editorPane.setDocument(htmlDoc);
frame.getContentPane().add(BorderLayout.CENTER, new JScrollPane(editorPane));
frame.setBounds(100, 100, 500, 400);
frame.setVisible(true);
}
}
The empty line after the <br> tag is not rendered. When the caret is positioned left of the 'a' char and the arrow up key is pressed, the caret disappears:
Before pressing 'up':
After pressing 'up':
Note that the distance between 'test' and 'a' is too small, and the caret has disappeared.
When you then enter text, the missing empty line becomes visible:
The problem seems to be that the empty line is rendered with a height of 0px, and thus is not visible, including the caret if it is on that line. Once the line has content, that content forces a non-zero line height.
Do you know a simple workaround / fix for this problem? I reckon in the worst case, I have to write my own editor kit (see also here and here for custom line wrapping in JEditorPane) and/or custom tag (also here).
Found a solution, using a custom editor kit:
public class MyEditorKit extends HTMLEditorKit {
private static final int MIN_HEIGHT_VIEWS = 10;
#Override
public ViewFactory getViewFactory() {
return new HTMLFactory() {
#Override
public View create(Element e) {
View v = super.create(e);
// Test for BRView must use String comparison, as the class is package-visible and not available to us
if ((v instanceof InlineView) && !v.getClass().getSimpleName().equals("BRView")) {
View v2 = new InlineView(e) {
#Override
public float getMaximumSpan(int axis) {
float result = super.getMaximumSpan(axis);
if (axis == Y_AXIS) {
result = Math.max(result, MIN_HEIGHT_VIEWS);
}
return result;
}
#Override
public float getMinimumSpan(int axis) {
float result = super.getMinimumSpan(axis);
if (axis == Y_AXIS) {
result = Math.max(result, MIN_HEIGHT_VIEWS);
}
return result;
}
#Override
public float getPreferredSpan(int axis) {
float result = super.getPreferredSpan(axis);
if (axis == Y_AXIS) {
result= Math.max(result, MIN_HEIGHT_VIEWS);
}
return result;
}
};
v = v2;
}
return v;
}
};
}
}
The editor kit returns a custom HTMLFactory. This factory creates custom InlineView objects for leaf elements, where the InlineView cannot have a height of 0. It will always have at least a MIN_HEIGHT_VIEW, which I set to 10 pixels (works reasonably well with default font sizes). The original implementation makes sense when rendering HTML just for viewing, as an empty line after a <br> tag should indeed be ignored. But for editing, users will expect to see the caret on the next line after inserting a linebreak.
I've recently been experimenting with the user of JTextPanes for an upcoming project I'll be working on, there have been various posts online detailing how to go about counting the number of lines within the text pane however the solutions I found all seem to fail when inserting Icons or Components into the text pane's document.
The solution I found that worked for plain text was this one (with the solution implemented of course): BadLocationException when using Utilities.getRowStart On hit of Enter key
However once I try to insert a Component (JLabel) or a plain Icon for that matter, the getRowStart() method from Utilities throws a null pointer exception. What I find unusual about this is the Java Doc states that "...This is represented in the associated document as an attribute of one character of content. ", so I assumed it would treat it as any other character but it seems this is not the case.
I've included a code example to replicate the problem if anyone would like to try it. I have a feeling that it just simply isn't possible, which would be a shame.
import java.awt.Dimension;
import java.awt.Image;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextPane;
import javax.swing.text.BadLocationException;
import javax.swing.text.Utilities;
public class Test{
private JFrame frame;
private JTextPane textPane;
private Image img;
private URL imgURL;
public Test(){
frame = new JFrame();
frame.setSize(new Dimension(500,300));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
textPane = new JTextPane();
try {
imgURL = new URL("http://www.freeiconspng.com/uploads/floppy-save-icon--23.png");
img = ImageIO.read(imgURL);
JLabel label = new JLabel(new ImageIcon(img.getScaledInstance(10, 10, Image.SCALE_SMOOTH)));
textPane.insertComponent(label);
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
frame.getContentPane().add(textPane);
frame.setVisible(true);
}
public JTextPane getTextPane(){
return this.textPane;
}
public int getLineCount(){
int totalCharacters = textPane.getDocument().getLength();
int lineCount = (totalCharacters == 0) ? 1 : 0;
try {
int offset = totalCharacters;
while (offset > 0) {
offset = Utilities.getRowStart(textPane, offset) - 1;
lineCount++;
}
} catch (BadLocationException e) {
e.printStackTrace();
}
return lineCount;
}
public static void main(String[] args){
Test t = new Test();
t.getLineCount();
}
}
The problem was solved after the following comment:
It doesn't throw any exception for me once I wrap the content inside
your main method inside a EventQueue.invokeLater() call. I.e.:
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
Test t = new Test();
t.getLineCount();
}
});
Does anyone knows how to get the part of the text from the beginning of JLabel to the pointer of the mouse? For example, let's say we have a JLabel with text 'C:\aaa\bbb\ccc'. The user points mouse pointer on characters 'bbb', so I would like to get the text 'C:\aaa\bbb'. Now, when I have this part of the text, I can change its color. I think will use html for that.
The Java Accessibility API conveniently includes a getIndexAtPoint method as part of the AccessibleText interface that converts a location (such as that of the mouse pointer) to the index of the character at that location:
Given a point in local coordinates, return the zero-based index of the character under that Point. If the point is invalid, this method returns -1.
Here is a test program that uses this method to get the part of the string you asked for:
import java.awt.BorderLayout;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.accessibility.AccessibleText;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class JLabelMouseDemo {
private static String labelText = "<html>C:\\aaa\\bbb\\ccc</html>";
private static JLabel label;
private static JLabel substringDisplayLabel;
public static void main(String[] args) {
JFrame frame = new JFrame();
label = new JLabel(labelText);
label.addMouseMotionListener(new MouseMotionAdapter() {
public void mouseMoved(MouseEvent e) {
AccessibleText accessibleText =
label.getAccessibleContext().getAccessibleText();
Point p = e.getPoint();
int index = accessibleText.getIndexAtPoint(p);
if (index >= 0) {
// The index is with respect to the actually displayed
// characters rather than the entire HTML string, so we
// must add six to skip over "<html>", which is part of
// the labelText String but not actually displayed on
// the screen. Otherwise, the substrings could end up
// something like "tml>C:\aaa"
index += 6;
// Strangely, in my testing, index was a one-based index
// (for example, mousing over the 'C' resulted in an
// index of 1), but this makes getting the part of the
// string up to that character easier.
String partOfText = labelText.substring(0, index);
// Display for demonstration purposes; you could also
// figure out how to highlight it or use the string or
// just the index in some other way to suit your needs.
// For example, you might want to round the index to
// certain values so you will line up with groups of
// characters, only ever having things like
// "C:\aaa\bbb", and never "C:\aaa\b"
substringDisplayLabel.setText(partOfText);
}
}
});
frame.add(label);
substringDisplayLabel = new JLabel();
frame.add(substringDisplayLabel, BorderLayout.SOUTH);
frame.setSize(200, 200);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
Actually obtaining an object of type AccessibleText that corresponds to a particular JLabel may not always work: as far as I can tell, it will only be possible when the JLabel is displaying HTML text. This also seems to be supported by the JLabel source:
public AccessibleText getAccessibleText() {
View view = (View)JLabel.this.getClientProperty("html");
if (view != null) {
return this;
} else {
return null;
}
}
I don't claim to fully understand what's going on in that code or why accessibility is not available for non-HTML text, but my test program did not work when the JLabel contained plain rather than HTML text: label.getAccessibleContext().getAccessibleText() would return null, and using a forced cast of (AccessibleText) label.getAccessibleContext() would yield an object that only ever returned -1 from getIndexAtPoint.
Edit: It is possible to get the part of the text without worrying about adjusting the indices based on the location of HTML tags that aren't displayed as visible text. You just have to maintain two copies of the string on the label: one containing only the characters to be displayed (rawText in the example below) that will be sliced according to the index, and one containing a formatted HTML version that will actually be used as the text of the label (the result of formatLabelText below). Because getIndexAtPoint returns an index relative only to the displayed characters, getting the desired substring is easier in the second example than my original one. The only adjustment made to index is rounding it up so that highlighted text lines up with the backslash-delimited groups.
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.accessibility.AccessibleText;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class JLabelMouseHighlightDemo {
private static String rawText = "C:\\aaa\\bbb\\ccc";
private static JLabel label;
private static String formatLabelText(int index) {
if (index < 0) {
index = 0;
}
if (index > rawText.length()) {
index = rawText.length();
}
StringBuilder sb = new StringBuilder();
sb.append("<html>");
sb.append("<font color='red'>");
sb.append(rawText.substring(0, index));
sb.append("</font>");
sb.append(rawText.substring(index));
sb.append("</html>");
return sb.toString();
}
private static int roundIndex(int index) {
// This method rounds up index to always align with a group of
// characters delimited by a backslash, so the red text will be
// "C:\aaa\bbb" instead of just "C:\aaa\b".
while (index < rawText.length() && rawText.charAt(index) != '\\') {
index++;
}
return index;
}
public static void main(String[] args) {
JFrame frame = new JFrame();
label = new JLabel(formatLabelText(0));
label.addMouseMotionListener(new MouseMotionAdapter() {
public void mouseMoved(MouseEvent e) {
AccessibleText accessibleText =
label.getAccessibleContext().getAccessibleText();
Point p = e.getPoint();
int index = accessibleText.getIndexAtPoint(p);
index = roundIndex(index);
label.setText(formatLabelText(index));
}
});
frame.add(label);
frame.setSize(200, 200);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
Here's a way to make #Alden's code work without storing the raw text anywhere. It turns out that getting the View from the JLabel gives you access to a version of the text with all the html stripped out.
import java.awt.BorderLayout;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.accessibility.AccessibleText;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.text.BadLocationException;
import javax.swing.text.View;
public class JLabelMouseDemo {
private static String labelText = "<html>C:\\aaa\\bbb\\ccc</html>";
private static JLabel label;
private static JLabel substringDisplayLabel;
public static void main(String[] args) {
JFrame frame = new JFrame();
label = new JLabel(labelText);
label.addMouseMotionListener(new MouseMotionAdapter() {
public void mouseMoved(MouseEvent e) {
AccessibleText accessibleText =
label.getAccessibleContext().getAccessibleText();
Point p = e.getPoint();
int index = accessibleText.getIndexAtPoint(p);
if (index >= 0) {
View view = (View) label.getClientProperty("html");
String strippedText = null;
try {
strippedText = view.getDocument().getText(0, accessibleText.getCharCount());
} catch (BadLocationException e1) {
e1.printStackTrace();
return;
}
// getIndexAtPoint seems to work from the end of a
// character, not the start, so you may want to add
// one to get the correct character
index++;
if (index > strippedText.length()) index = strippedText.length();
String partOfText = strippedText.substring(0, index);
// Display for demonstration purposes; you could also
// figure out how to highlight it or use the string or
// just the index in some other way to suit your needs.
substringDisplayLabel.setText(partOfText);
}
}
});
frame.add(label);
substringDisplayLabel = new JLabel();
frame.add(substringDisplayLabel, BorderLayout.SOUTH);
frame.setSize(200, 200);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
I had some problems with freezing SWING GUIs when re-rendering a JTable with a custom cell renderer in Java. So I asked the question "Why does a JTable view update block the entire GUI?". The answers pointed to the fact, that a JList without modifying JTable and overwriting doLayout might be a better choice. So I implemented the example with a JList and ran into the same problem: while generating data, everything works fine and the progress bar moves. But when the view is updated, the program freezes and the progress bar stops moving.
Please note, that the sleep statement is there only to let the generation take a longer, more realistic time (reading thousands of data sets via JDBC and create objects out of them takes a lot time). One could remove it and increment the number of generated items. But you can clearly see, that the HTML rendering is quite slow. But I need this colors and the two lines (if not necessarily so many different colors).
So could you please tell me, where my mistake is? I think, that EDT and other work is separated through separate threads and I cannot see any mistke.
Update: I looked around at SO and found this question "https://stackoverflow.com/a/20813122/2429611". There is said:
The more interesting question would be how to avoid that UI blocking, but I don't think that's possible with just Swing, you'll have to implement some lazy loading, or rendering in batches.
This would mean, that I cannot solve my problem. Is this correct?
package example;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.AbstractListModel;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JScrollPane;
import javax.swing.ListCellRenderer;
import javax.swing.SwingUtilities;
public class ListExample extends AbstractListModel {
static List<DemoObject> internalList = new ArrayList<>();
#Override
public int getSize() {
return internalList.size();
}
#Override
public DemoObject getElementAt(int index) {
return internalList.get(index);
}
public void fireContentsChanged() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
fireContentsChanged(this, 0, -1);
}
});
}
static class MyCellRenderer extends JLabel implements ListCellRenderer<ListExample.DemoObject> {
public MyCellRenderer() {
setOpaque(true);
}
#Override
public Component getListCellRendererComponent(JList<? extends ListExample.DemoObject> list,
ListExample.DemoObject value,
int index,
boolean isSelected,
boolean cellHasFocus) {
setText("<html>" + value.toString()
+ "<br/>"
+ "<span bgcolor=\"#ff0000\">Line 2; Color = " + value.c + "</span>");
Color background;
Color foreground;
// check if this cell represents the current DnD drop location
JList.DropLocation dropLocation = list.getDropLocation();
if (dropLocation != null
&& !dropLocation.isInsert()
&& dropLocation.getIndex() == index) {
background = Color.BLUE;
foreground = Color.WHITE;
// check if this cell is selected
} else if (isSelected) {
background = Color.RED;
foreground = Color.WHITE;
// unselected, and not the DnD drop location
} else {
background = value.c; //Color.WHITE;
foreground = Color.BLACK;
};
setBackground(background);
setForeground(foreground);
return this;
}
}
static class DemoObject {
String str;
Color c;
public DemoObject(String str, int color) {
this.str = str;
this.c = new Color(color);
}
#Override
public String toString() {
return str;
}
}
static JPanel overlay;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Example");
frame.setLayout(new BorderLayout(4, 4));
// Add JTable
final ListExample model = new ListExample();
JList list = new JList(model);
list.setCellRenderer(new MyCellRenderer());
frame.add(new JScrollPane(list), BorderLayout.CENTER);
// Add button
Box hBox = Box.createHorizontalBox();
hBox.add(new JButton(new AbstractAction("Load data") {
#Override
public void actionPerformed(ActionEvent e) {
new Thread(new Runnable() {
#Override
public void run() {
overlay.setVisible(true);
internalList.clear();
System.out.println("Generating data ...");
SecureRandom sr = new SecureRandom();
for (int i = 0; i < 10000; i++) {
internalList.add(
new DemoObject(
"String: " + i + " (" + sr.nextFloat() + ")",
sr.nextInt(0xffffff)
)
);
// To create the illusion, that data are
// fetched via JDBC (which takes a little
// while), this sleep statement is embedded
// here. In a real world scenario, this wait
// time is caused by talking to the database
// via network
if (i%10 == 0) {
try {
Thread.sleep(1);
} catch (Exception e) {
}
}
}
System.out.println("Updating view ...");
model.fireContentsChanged();
overlay.setVisible(false);
System.out.println("Finished.");
}
}).start();
}
}));
hBox.add(Box.createHorizontalGlue());
frame.add(hBox, BorderLayout.NORTH);
// Create loading overlay
overlay = new JPanel(new FlowLayout(FlowLayout.CENTER)) {
#Override
protected void paintComponent(Graphics g) {
g.setColor(new Color(0, 0, 0, 125));
g.fillRect(0, 0, getWidth(), getHeight());
super.paintComponent(g);
}
};
overlay.setOpaque(false);
overlay.setBackground(new Color(0, 0, 0, 125));
JProgressBar bar = new JProgressBar();
bar.setIndeterminate(true);
overlay.add(bar);
frame.setGlassPane(overlay);
frame.getGlassPane().setVisible(false);
// Create frame
frame.setSize(600, 400);
frame.setVisible(true);
}
});
}
}
there are three problems (recreating, reseting the model, and custom Renderer stoped to works)
JList (JComboBox hasn't) has an issue by removing more than 999 items, you have to set a new model to JList
see important for ComboBoxModel extends AbstractListModel implements MutableComboBoxModel for setElementAt(to hold current selection)
usage of public void fireContentsChanged() { is wrong, don't see reason to use this way, again is about to replace current, reset the model
. e.g. with success atr runtime and by recrusive testing for/if event (fired)
setModel(new DefaultListModel(list.toArray()) {
protected void fireContentsChanged(Object obj, int i, int j) {
if (!isFired)
super.fireContentsChanged(obj, i, j);
}
});