JScrollPane with JTextArea
I'm creating a program where a user enters a string into a JTextField and then that string is appended to a new line in a JTextArea that is inside of a JScrollPane. I wanted to know how I could make it so that each time a line is appended to the JTextArea that the JScrollPane scrolls down to the bottom left, showing the new line? (If i don't touch the JScrollPane, this works on its own but after I scroll around it doesnt update the view to the bottom anymore).
Thanks,
swing can be a bit confusing at times.
http://java.sun.com/docs/books/tutorialJWS/uiswing/components/ex6/TextDemo.jnlp
http://java.sun.com/docs/books/tutorial/uiswing/components/textfield.html
Similar Messages
-
Stop JScrollpane if JTextarea is full
I've put a JTextArea with 27 rows on a JScrollpane with vertical scrollbar policy. And I want the JScrollPane to stop scrolling if the 27th row of the Textarea is full.
But it scrolls and scrolls and adds further rows to the
JTextArea... :-(
Any idea???
sickiFound a solution:
Write your own Component. Inherit from JTextArea and override the createDefaultModel-Method.
protected Document createDefaultModel() {
return new LimitedDocument();
static class LimitedDocument extends PlainDocument {
// Begrenzung dieses Dokumentes (also der TextAreas):
static final int LIMIT = 10;
public void insertString(int offs, String str, AttributeSet a)
throws BadLocationException {
if (str != null) {
if (offs < LIMIT) {
super.insertString(offs, str, a);
else {
// Falls keine Zeichen mehr eingegeben werden d�rfen, wird gepiepst.
Toolkit.getDefaultToolkit().beep();
} -
JScrollPane with scrollbar as needed packs to the wrong size.
Hi!
I just noticed a strange problem when packing a JScrollPane with scrollbar policy "as needed" and wondered if it's me or if it is a real bug in Swing.
I create a JFrame with a JScrollPane in it and a JPanel as viewportview. The JPanel (called "stuffPanel") contains a few components which give it a preferred size, and the JScrollPane is set to grow as needed if the window grows. A button in the center of the stuffPanel will invoke pack() on the window when clicked.
Now, if I resize the window such that the JScrollPane can't display the entire stuffPanel, I get scrollbars as expected. If I click the pack button the window correctly resizes to the preferred size (without scrollbars).
On the other hand, if I resize the window to become larger than the preferred size and then click the pack button, the window (and the stuffPanel) is resized to include 17 pixels of extra size around the edges.
Put simply, pack() will resize the JPanel to different sizes depending on whether the scrollbars of the JScrollPane were visible at the time. Note that this only occurs when you're using the "scrollbars as needed" scrollbar policy.
An even more interesting situation occurs if you resize the window to include (for example) only horizontal scrollbars and then packs the window repeatedly...
Code for a Java app which displays the strange behaviour is included below:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TestJScrollPane {
static {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
catch (Exception e) { }
private JFrame mainWindow;
public TestJScrollPane() {
mainWindow = createMainWindow();
mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainWindow.pack();
mainWindow.show();
public JFrame createMainWindow() {
JFrame window = new JFrame("Test of scrollpane");
window.getContentPane().setLayout(new GridBagLayout());
final JPanel stuffPanel = new JPanel();
stuffPanel.setBorder(BorderFactory.createTitledBorder("Collection of stuff"));
stuffPanel.setLayout(new GridBagLayout());
JLabel stuffLabel = new JLabel("A label");
JTextField stuffField = new JTextField(10);
JButton stuffButton = new JButton("Pack the window");
JList listOfStuff = new JList();
listOfStuff.setListData(new String[] {"Fish", "Bird", "Mammal", "Insect", "Spider"});
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
stuffPanel.add(stuffLabel, gbc);
gbc.gridx = 1;
stuffPanel.add(stuffField, gbc);
gbc.gridy = 1;
gbc.gridx = 0;
gbc.gridwidth = 2;
stuffPanel.add(stuffButton, gbc);
gbc.gridy = 2;
gbc.fill = GridBagConstraints.BOTH;
stuffPanel.add(listOfStuff, gbc);
final JScrollPane scroller = new JScrollPane(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scroller.setViewportView(stuffPanel);
gbc = new GridBagConstraints();
gbc.fill = GridBagConstraints.BOTH;
gbc.weightx = 1;
gbc.weighty = 1;
window.getContentPane().add(scroller, gbc);
stuffButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
mainWindow.pack();
System.out.println("Stuff panel size: " + stuffPanel.getSize());
System.out.println("Stuff panel preferred size:" + stuffPanel.getPreferredSize());
System.out.println("Scroller size: " + scroller.getSize());
System.out.println("Scroller preferred size: " + scroller.getPreferredSize());
return window;
public static void main(String[] args) {
new TestJScrollPane();
}Why would the JScrollPane be as big as the entire
frame when you added 800x600 panels on all sides of
it? It's going to be in the center surrounded by
huge panels. Thanks, kablair. However, if you look at the code, these panels are not 800x600 on all sides. The north and south panels only add a combined height of 100, and the east and west panels only add a combined width of 100. so the whole window, minus insets, should be 900x700.
Anyway, i took the advice of the guy above, and that has gotten me much closer. In the bigger app that I'm trying to calculate the size, now I'm only 2 pixels away from the true size, although I can't figure out what I'm forgetting. -
Need help with JTextArea and Scrolling
import java.awt.*;
import java.awt.event.*;
import java.text.DecimalFormat;
import javax.swing.*;
public class MORT_RETRY extends JFrame implements ActionListener
private JPanel keypad;
private JPanel buttons;
private JTextField lcdLoanAmt;
private JTextField lcdInterestRate;
private JTextField lcdTerm;
private JTextField lcdMonthlyPmt;
private JTextArea displayArea;
private JButton CalculateBtn;
private JButton ClrBtn;
private JButton CloseBtn;
private JButton Amortize;
private JScrollPane scroll;
private DecimalFormat calcPattern = new DecimalFormat("$###,###.00");
private String[] rateTerm = {"", "7years @ 5.35%", "15years @ 5.5%", "30years @ 5.75%"};
private JComboBox rateTermList;
double interest[] = {5.35, 5.5, 5.75};
int term[] = {7, 15, 30};
double balance, interestAmt, monthlyInterest, monthlyPayment, monPmtInt, monPmtPrin;
int termInMonths, month, termLoop, monthLoop;
public MORT_RETRY()
Container pane = getContentPane();
lcdLoanAmt = new JTextField();
lcdMonthlyPmt = new JTextField();
displayArea = new JTextArea();//DEFINE COMBOBOX AND SCROLL
rateTermList = new JComboBox(rateTerm);
scroll = new JScrollPane(displayArea);
scroll.setSize(600,170);
scroll.setLocation(150,270);//DEFINE BUTTONS
CalculateBtn = new JButton("Calculate");
ClrBtn = new JButton("Clear Fields");
CloseBtn = new JButton("Close");
Amortize = new JButton("Amortize");//DEFINE PANEL(S)
keypad = new JPanel();
buttons = new JPanel();//DEFINE KEYPAD PANEL LAYOUT
keypad.setLayout(new GridLayout( 4, 2, 5, 5));//SET CONTROLS ON KEYPAD PANEL
keypad.add(new JLabel("Loan Amount$ : "));
keypad.add(lcdLoanAmt);
keypad.add(new JLabel("Term of loan and Interest Rate: "));
keypad.add(rateTermList);
keypad.add(new JLabel("Monthly Payment : "));
keypad.add(lcdMonthlyPmt);
lcdMonthlyPmt.setEditable(false);
keypad.add(new JLabel("Amortize Table:"));
keypad.add(displayArea);
displayArea.setEditable(false);//DEFINE BUTTONS PANEL LAYOUT
buttons.setLayout(new GridLayout( 1, 3, 5, 5));//SET CONTROLS ON BUTTONS PANEL
buttons.add(CalculateBtn);
buttons.add(Amortize);
buttons.add(ClrBtn);
buttons.add(CloseBtn);//ADD ACTION LISTENER
CalculateBtn.addActionListener(this);
ClrBtn.addActionListener(this);
CloseBtn.addActionListener(this);
Amortize.addActionListener(this);
rateTermList.addActionListener(this);//ADD PANELS
pane.add(keypad, BorderLayout.NORTH);
pane.add(buttons, BorderLayout.SOUTH);
pane.add(scroll, BorderLayout.CENTER);
addWindowListener( new WindowAdapter()
public void windowClosing(WindowEvent e)
System.exit(0);
public void actionPerformed(ActionEvent e)
String arg = lcdLoanAmt.getText();
int combined = Integer.parseInt(arg);
if (e.getSource() == CalculateBtn)
try
JOptionPane.showMessageDialog(null, "Got try here", "Error", JOptionPane.ERROR_MESSAGE);
catch(NumberFormatException ev)
JOptionPane.showMessageDialog(null, "Got here", "Error", JOptionPane.ERROR_MESSAGE);
if ((e.getSource() == CalculateBtn) && (arg != null))
try{
if ((e.getSource() == CalculateBtn) && (rateTermList.getSelectedIndex() == 1))
monthlyInterest = interest[0] / (12 * 100);
termInMonths = term[0] * 12;
monthlyPayment = combined * (monthlyInterest / (1 - (Math.pow (1 + monthlyInterest, -termInMonths))));
lcdMonthlyPmt.setText(calcPattern.format(monthlyPayment));
if ((e.getSource() == CalculateBtn) && (rateTermList.getSelectedIndex() == 2))
monthlyInterest = interest[1] / (12 * 100);
termInMonths = term[1] * 12;
monthlyPayment = combined * (monthlyInterest / (1 - (Math.pow (1 + monthlyInterest, -termInMonths))));
lcdMonthlyPmt.setText(calcPattern.format(monthlyPayment));
if ((e.getSource() == CalculateBtn) && (rateTermList.getSelectedIndex() == 3))
monthlyInterest = interest[2] / (12 * 100);
termInMonths = term[2] * 12;
monthlyPayment = combined * (monthlyInterest / (1 - (Math.pow (1 + monthlyInterest, -termInMonths))));
lcdMonthlyPmt.setText(calcPattern.format(monthlyPayment));
catch(NumberFormatException ev)
JOptionPane.showMessageDialog(null, "Invalid Entry!\nPlease Try Again", "Error", JOptionPane.ERROR_MESSAGE);
} //IF STATEMENTS FOR AMORTIZATION
if ((e.getSource() == Amortize) && (rateTermList.getSelectedIndex() == 1))
loopy(7, 5.35);
if ((e.getSource() == Amortize) && (rateTermList.getSelectedIndex() == 2))
loopy(15, 5.5);
if ((e.getSource() == Amortize) && (rateTermList.getSelectedIndex() == 3))
loopy(30, 5.75);
if (e.getSource() == ClrBtn)
rateTermList.setSelectedIndex(0);
lcdLoanAmt.setText(null);
lcdMonthlyPmt.setText(null);
displayArea.setText(null);
if (e.getSource() == CloseBtn)
System.exit(0);
private void loopy(int lTerm,double lInterest)
double total, monthly, monthlyrate, monthint, monthprin, balance, lastint, paid;
int amount, months, termloop, monthloop;
String lcd2 = lcdLoanAmt.getText();
amount = Integer.parseInt(lcd2);
termloop = 1;
paid = 0.00;
monthlyrate = lInterest / (12 * 100);
months = lTerm * 12;
monthly = amount *(monthlyrate/(1-Math.pow(1+monthlyrate,-months)));
total = months * monthly;
balance = amount;
while (termloop <= lTerm)
displayArea.setCaretPosition(0);
displayArea.append("\n");
displayArea.append("Year " + termloop + " of " + lTerm + ": payments\n");
displayArea.append("\n");
displayArea.append("Month\tMonthly\tPrinciple\tInterest\tBalance\n");
monthloop = 1;
while (monthloop <= 12)
monthint = balance * monthlyrate;
monthprin = monthly - monthint;
balance -= monthprin;
paid += monthly;
displayArea.setCaretPosition(0);
displayArea.append(monthloop + "\t" + calcPattern.format(monthly) + "\t" + calcPattern.format(monthprin) + "\t");
displayArea.append(calcPattern.format(monthint) + "\t" + calcPattern.format(balance) + "\n");
monthloop ++;
termloop ++;
public static void main(String args[])
MORT_RETRY f = new MORT_RETRY();
f.setTitle("MORTGAGE PAYMENT CALCULATOR");
f.setBounds(600, 600, 500, 500);
f.setLocationRelativeTo(null);
f.setVisible(true);
}need help with displaying the textarea correctly and the scroll bar please.
Message was edited by:
new2this2020What's the problem you're having ???
PS. -
Problem with JTextArea or is it my code, Help!!!
Hi,
I am going crazy. I am sending a message to a JTextArea and I get some very wierd things happening? I really need help because this is driving me crazy. Please see the following code to see my annotations for the problems. Has anyone else experienced problems with this component?
Thanks,
Steve
// THIS IS THE CLASS THAT HANDLES ALL OF THE WORK
public class UpdateDataFields implements ActionListener { // 400
JTextArea msg;
JPanel frameForCardPane;
CardLayout cardPane;
TestQuestionPanel fromRadio;
public UpdateDataFields( JTextArea msgout ) { // 100
msg = msgout;
} // 100
public void actionPerformed(ActionEvent evt) { // 200
String command = evt.getActionCommand();
String reset = "Test of reset.";
try{
if (command.equals("TestMe")){ // 300
msg.append("\nSuccessful");
Interface.changeCards();
} // 300
catch(Exception e){
e.printStackTrace();
try{
if (command.equals("ButtonA")){ // 300
// WHEN I CALL BOTH OF THE FOLLOWING METHODS THE DISPLAY WORKS
// BUT THE CHANGECARDS METHOD DOES NOT WORK. WHEN I COMMENT OUT
// THE CALL TO THE DISPLAYMESSAGE METHOD THEN THE CHANGECARDS WORKS
// FINE. PLEASE THE INTERFACE CLASS NEXT.
Interface.changeCards();
Interface.displayMessage("test of xyz");
} // 300
catch(Exception e){
e.printStackTrace();
} // 200
} // 400
// END OF UPDATEDATAFIELS END END END
public class Interface extends JFrame { // 300
static JPanel frameForCardPane;
static CardLayout cardPane;
static JTextArea msgout;
TestQuestionPanel radio;
Interface () { // 100
super("This is a JFrame");
setSize(800, 400); // width, height
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// set-up card layout
cardPane = new CardLayout();
frameForCardPane = new JPanel(); // for CardLayout
frameForCardPane.setLayout(cardPane); // set the layout to cardPane = CardLayout
TestQuestionPanel cardOne = new TestQuestionPanel("ABC", "DEF", msgout, radio);
TestQuestionPanel cardTwo = new TestQuestionPanel("GHI", "JKL", msgout, radio);
frameForCardPane.add(cardOne, "first");
frameForCardPane.add(cardTwo, "second");
// end set-up card layout
// set-up main pane
// declare components
msgout = new JTextArea( 8, 40 );
ButtonPanel commandButtons = new ButtonPanel(msgout);
JPanel pane = new JPanel();
pane.setLayout(new GridLayout(2, 4, 5, 15)); pane.setBorder(BorderFactory.createEmptyBorder(30, 20, 10, 30));
pane.add(frameForCardPane);
pane.add( new JScrollPane(msgout));
pane.add(commandButtons);
msgout.append("Successful");
setContentPane(pane);
setVisible(true);
} // 100
// HERE ARE THE METHODS THAT SHOULD HANDLE THE UPDATING
static void changeCards() { // 200
cardPane.next(frameForCardPane);
System.out.println("Calling methods works!");
} // 200
static void displayMessage(String test) { // 200
String reset = "Test of reset.";
String passMessage = test;
cardPane.next(frameForCardPane);
System.out.println("Calling methods works!");
msgout.append("\n"+ test);
} // 200
} // 300Hi,
I instantiate it in this class. Does that change your opinion or the advice you gave me? Please help!
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class CardLayoutQuestionsv2 {
public static void main(String[] arguments) {
JFrame frame = new Interface();
frame.show();
} -
No Scroll bar with JTextArea on unix machine
hi am using JTextArea with Unix machine... The problem is not enabling scroll bars
can anyone help meJTextArea agreeTxt;
agreeTxt = new JTextArea(11, 42);
agreeTxt.setAutoscrolls(true);
agreeTxt.setLineWrap(true);
agreeTxt.setEditable(false);
JScrollPane pane = new JScrollPane( agreeTxt );Now add the JScrollPane object to your JPanel or where ever you have your JTextArea -
Displaying progress with JTextArea
Hi,
As newbie, I'm trying to test a concept to see if I can get the new data be appended and displayed immediately in a JTextArea. I wrote a little application that display the number as it loops through in actionPermformed interface. I put a short pause so I can see the number being refreshed into JtextArea. However, what I get is the application process all the loop and repaint the text area with all numbers. As a result, I don't the get progressing paint effect as the application loop through in for loop. What method I should use to achieve this effect? Here is the code I use.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Loop extends JFrame implements ActionListener{
JTextArea taNum = null;
JButton btnLoop = null;
JTextField tfNum = null;
JScrollPane jspNum= null;
public Loop (){
setSize (100,200);
setLocationRelativeTo(null);
Container pane = getContentPane();
pane.setLayout (new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.WEST;
tfNum = new JTextField(10);
c.gridx=0;
c.gridy=0;
pane.add(tfNum,c);
btnLoop = new JButton ("Loop");
btnLoop.addActionListener(this);
c.gridx=1;
c.gridy=0;
pane.add(btnLoop,c);
taNum = new JTextArea("Start",5,20);
jspNum = new JScrollPane(taNum);
c.gridx=0;
c.gridy=2;
c.gridwidth=2;
c.gridheight=2;
c.ipady=20;
pane.add(jspNum,c);
pack();
setVisible(true);
public void actionPerformed (ActionEvent e){
try{
for (int i =0;i<Integer.parseInt(tfNum.getText());i++){
taNum.append(Integer.toString(i)+'\n');
taNum.setCaretPosition(taNum.getDocument().getLength());
repaint();
Thread.sleep(500);
} catch (InterruptedException ex){
ex.printStackTrace();
public static void main (String [] argv){
Loop l = new Loop();
/*************************************/Thank in advance.
Kim
Edited by: kimtitu on Oct 1, 2010 2:03 PM1) Read the "Welcome to the new home" posting at the top of the forum for information on the proper way to add code to a posting
2) Swing related questions should be posted in the Swing forum which is found under "Java Desktop" from the forums home page.
3) Read the section from the Swing tutorial on [url http://download.oracle.com/javase/tutorial/uiswing/concurrency/index.html]Concurrency for more information about why it doesn't work and for one possible solution. -
Preventing text echo with JTextArea
Hello,
I have a textarea that reads in the input from a serial port. I need a way to stop the local echo when the user types into the text area. I have tried googling but i have not been able to find anything. Any tips or hints would be greatly appreciated.
Thank you,
hammackjNot sure how to set up this secret component. Perhaps
a glass pane that covers the entire GUI? I have no
experience with actually doing that.
One way of doing this would be to override the JTextArea's processEvent(AWTEvent) method. The new implementation can intercept any key events and send the typed characters to the serial port. This small program shows how this can be done (the program simply writes the intercepted characters to the console):
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class KeyInterceptTest extends JFrame {
public KeyInterceptTest() {
setDefaultCloseOperation(EXIT_ON_CLOSE);
getContentPane().setLayout(new BorderLayout());
JTextArea text = new JTextArea(5, 30) {
protected void processEvent(AWTEvent e) {
if( e instanceof KeyEvent ) {
// Intercept all KeyEvents
if( e.getID() == KeyEvent.KEY_TYPED) {
// For keyTyped events we print the typed character to the console
System.out.print(((KeyEvent)e).getKeyChar());
else {
// Let non-KeyEvents pass on to the default implementation
super.processEvent(e);
getContentPane().add(new JScrollPane(text), BorderLayout.CENTER);
JButton close = new JButton("Close");
close.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
getContentPane().add(close, BorderLayout.SOUTH);
pack();
setLocationRelativeTo(null);
public static void main(String[] args) {
new KeyInterceptTest().setVisible(true);
}The advantage of this approach, assuming that the typed characters eventually will be echoed back to the text area, would be that the user would still "feel" he/she is actually typing in the text area. -
JScrollPane w/ JTextArea problems
I've written a simple terminal for a project I'm working on, with a JTextField for inputs and a JTextArea to display outputs. The JTextArea uses a JScrollPane to let it scroll vertically, and wraps text to avoid horizontal scrolling.
My problem is this: when I append text to the text area, the scroll pane sometimes scrolls to the bottom, sometimes scrolls part-way, and sometimes doesn't move at all. Ideally, I'd like to have the scroll pane always pushed to the bottom. Does anyone know what causes this kind of behaviour? What input causes the bar to scroll, and what input doesn't?
thanks,
AndrewI don't know what causes the kind if behaviour you described, but this is how you get the scrollPane to scroll to the bottom:
int bottom = scrollPane.getVerticalScrollBar().getMaximum();
scrollPane.getVerticalScrollBar().setValue(bottom); -
Please Help with JtextArea!! Need advice from Java expert!
Hi, I need something VERY simple, and it is unbelievable I'm looking for a solution for so long! I really hope some of you java-gurus can help me out. Here's the thing:
1. Make a Jframe
2. Add a JTextArea and use a transparent color (e.g. 0.1f,0.1f,0.1f,0.1f)
3. loop a setText method to display a constantly varying text, e.g. the time in milliseconds
I simply can't do it in any way if I use transparency. Without transparency it works with no problems.
I am on Mac, and I have checked out this site:
http://www.curious-creature.org/2007/04/10/translucent-swing-windows-on-mac-os-x/
but I can't figure out how the guy who wrote the code made it work on mac (he didn't add the full code and the imports). I already tried to contact him, but no answer...
so PLEEEEASE take 5 minutes to write a very small example of how to manage a varying text on a transparent window.
Thanks a lot in advance
Lele-> did you maybe check out the link I posted?
Yes, I did which is why I asked the question are you trying to create a transparent JFrame so that the desktop image is displayed in the frame? To my knowledge this feature (if it works) is a Mac only feature and does not work on windows. If this is what you are trying to do then I have no idea how to do it and will not respond any more.
-> the GPS coordinates are displayed on top of the moving map, with no visible background
I guess I have trouble understanding what this is - "a map with no background"?
Is the map just not an image (ie. a JLabel with an ImageIcon) placed in a scrollpane? Then as the map moves you change the viewport position so it looks like the map is moving? Then you can simply add a label containing the GPS coordinates on top of the label representing the map.
-> have you considered using a JLabel in an OverlayLayout?
Right which is what I was thinking. Something simple like:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LabelMap extends JFrame
public LabelMap()
JLabel map = new JLabel(new ImageIcon("yourMap.jpg"));
getContentPane().add(new JScrollPane(map));
JLabel point = new JLabel();
point.setLocation(50, 50);
point.setText(point.getLocation().toString());
Dimension d = point.getPreferredSize();
point.setSize(d.width, d.height);
point.setFocusable(true);
map.add(point);
KeyListener kl = new KeyAdapter()
public void keyPressed(KeyEvent e)
JLabel point = (JLabel)e.getSource();
Point p = point.getLocation();
if (e.getKeyCode() == KeyEvent.VK_UP)
p.y -= 5;
else if (e.getKeyCode() == KeyEvent.VK_DOWN)
p.y += 5;
else if (e.getKeyCode() == KeyEvent.VK_LEFT)
p.x -= 5;
else if (e.getKeyCode() == KeyEvent.VK_RIGHT)
p.x += 5;
point.setLocation(p);
point.setText(p.getLocation().toString());
Dimension d = point.getPreferredSize();
point.setSize(d.width, d.height);
point.addKeyListener(kl);
public static void main(String[] args)
LabelMap frame = new LabelMap();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.setSize(300, 300);
frame.setLocationRelativeTo( null );
frame.setVisible(true);
}In the above example you can scroll the image and dynamically move the text using the arrow keys. -
I am having two problems:
1) I need to know how to create a JTextArea that holds a finite amount of information, like 8 lines... is this possible without Listeners? Perhaps using setColumns or setWidths? I wasn't actually sure what those methods did because they didn't work for me.
2) I need to create the Text area without Horizontal scrollbars... I can't do regular implementation as I have seen in previous postings because I am using BreezySwing where the constructor is:
JTextArea field = addTextArea ("Type Text Here",1,1,2,1);
with no space to add the scrollbar policy. I also tried to add a scroll pane
JScrollPane pane = new JScrollPane(field, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
but it just greyed out my field so it wasn't editable.
3) I want to read in all of the information that is in the text area into a string
but I do not know how to tell when to end a loop that reads in all the informaiton. Is there a method that determines the last word in a text area?
Is is possible to read in each row of text as a different string?
--Thank you very much,
Evan.
Sorry if my questions are amatuer-- I'm a novice and my computer science class is geared towards AP knowledge-- which doesn't cover swing... I'm just interested.
Message was edited by:
EvanDRead the tutorial:
http://java.sun.com/docs/books/tutorial/uiswing/components/textarea.html
1. Use setRows(8).
If you want to stop the user from entering more text after the 8 lines you will have to use a DocumentFilter for this.
You can read here Implementing a Document Filter:
http://java.sun.com/docs/books/tutorial/uiswing/components/generaltext.html#filter
2. You need to use setLineWrap(true) and maybe also setWrapStyleWord(true) depending on your needs.
3. You can use getLineCount, getLineStartOffset, getLineEndOffset with getText(offset, length) to iterate over the text and read 1 line at a time. -
Hi all,
I am having a class which extends JTextArea. I press backspace and I check for some condition in KeyReleased event. If the condition is true I am setting the JTextArea with the old text(retainText). What happens here is that first the backspace entered by me is reflecting on the screen and then only the new text (retainText) is set. This causes a flickering on the text area. My requirement is that this should not happen.
Is there any way to avoid this .
or else Is there any way to cancel this event ( say i enter backspace and if the condition becomes true in the KeyReleased event, I should stop this event. Can any body please help me ASAP. Thanks!!!
I ve attached the code also
package com.bankofny.iic.client.component;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.text.*;
import com.bankofny.iic.client.instruction.viewer.TradeDetailForm;
import com.bankofny.iic.common.util.StringFormatter;
public class IicTextAreaSwift extends JTextArea implements FocusListener, KeyListener
// IicTextAreaSwift Method
private int DescCharWidth = 0;
private int DescCharHeight =0;
private String retainText; //retain always the latest text
private int KeyCode;
private String KeyText="";
public IicTextAreaSwift(int _rows, int _columns, boolean scrollPane)
super(_rows, _columns + 1);
setDisabledTextColor(Color.gray);
rows = _rows;
columns = _columns;
setRows(_rows);
maxTextAllowed = _rows * _columns;
setBorder(new BevelBorder(BevelBorder.LOWERED));
setLineWrap(true);
setWrapStyleWord(true);
Font fixedFont = new Font("Courier", Font.PLAIN, 12);
setFont(fixedFont);
FontMetrics fm = getFontMetrics(fixedFont);
DescCharWidth = fm.charWidth('W') * (_columns + 1);
// DescCharHeight = fm.getHeight() * 4 ;
DescCharHeight = DEFAULT_LABEL_HEIGHT * 3;
setPreferredSize(new Dimension(DescCharWidth, DescCharHeight));
// setSize(new Dimension(DescCharWidth, DescCharHeight));
addKeyListener(this);
addFocusListener(this);
fixTAB();
public IicTextAreaSwift(int _rows, int _columns)
super(_rows, _columns);
// HA this constructor is for this field not in a scroll pane
setDisabledTextColor(Color.gray);
rows = _rows;
columns = _columns;
setRows(_rows);
maxTextAllowed = _rows * _columns;
setBorder(new BevelBorder(BevelBorder.LOWERED));
setLineWrap(true);
setWrapStyleWord(true);
Font fixedFont = new Font("Courier", Font.PLAIN, 12);
setFont(fixedFont);
FontMetrics fm = getFontMetrics(fixedFont);
DescCharWidth = fm.charWidth('W') * (_columns + 1);
// DescCharHeight = fm.getHeight() * 4 ;
DescCharHeight = DEFAULT_LABEL_HEIGHT * 3;
setPreferredSize(new Dimension(DescCharWidth, DescCharHeight));
// setSize(new Dimension(DescCharWidth, DescCharHeight));
addKeyListener(this);
addFocusListener(this);
fixTAB();
public Dimension getDimen()
return new Dimension( DescCharWidth, DescCharHeight);
public void showKeys(JComponent component)
// List keystrokes in the WHEN_FOCUSED input map of the component
InputMap map = component.getInputMap(JComponent.WHEN_FOCUSED);
printInputMap(map,"WHEN_FOCUSED");
// List keystrokes in the WHEN_ANCESTOR_OF_FOCUSED_COMPONENT input map of the component
map = component.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
printInputMap(map,"WHEN_ANCESTOR_OF_FOCUSED_COMPONENT");
//list(map, map.keys());
// List keystrokes in all related input maps
//list(map, map.allKeys());
// List keystrokes in the WHEN_IN_FOCUSED_WINDOW input map of the component
map = component.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
printInputMap(map,"WHEN_IN_FOCUSED_WINDOW");
printActionMap( getActionMap() , "JTextArea");
//list(map, map.keys());
// List keystrokes in all related input maps
// list(map, map.allKeys());
public void fixTAB()
Set newForwardKeys = new HashSet ();
newForwardKeys.add(KeyStroke.getKeyStroke(KeyEvent.VK_TAB, 0, false));
this.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, newForwardKeys);
Set newBackwardKeys = new HashSet ();
newBackwardKeys.add(KeyStroke.getKeyStroke(KeyEvent.VK_TAB, InputEvent.SHIFT_MASK, false));
this.setFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, newBackwardKeys);
Set forwardKeys = this.getFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
// System.out.println ("Desktop forward focus traversal keys: " + forwardKeys);
Set backwardKeys = this.getFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS);
// System.out.println ("Desktop backward focus traversal keys: " + backwardKeys);
this.setFocusTraversalKeysEnabled(true);
public static void printActionMap(ActionMap actionMap, String who)
{ // System.out.println("Action map for " + who + ":");
Object[] keys = actionMap.allKeys();
if (keys != null)
for (int i = 0; i < keys.length; i++)
Object key = keys;
Action targetAction = actionMap.get(key);
// System.out.println("\tName: <" + key + ">, action: " + targetAction.getClass().getName());
public static void printInputMap(InputMap inputMap, String heading)
//System.out.println("\n" + heading + ":");
KeyStroke[] keys = inputMap.allKeys();
if (keys != null)
for (int i = 0; i < keys.length; i++)
KeyStroke key = keys[i];
Object actionName = inputMap.get(key);
// System.out.println("\tKey: <" + key + ">, action name: " + actionName);
public void paste()
public void focusGained(java.awt.event.FocusEvent event)
//System.out.println("Hman " + event.paramString());
if(event.getOppositeComponent() != null)
if(event.getOppositeComponent().getParent() != null)
if (findRoot(event.getOppositeComponent()) != null && findRoot(this) != null)
if ( isEnabled() && findRoot(event.getOppositeComponent()) == findRoot(this))
selectAll();
public Component findRoot(Component _cc)
while (_cc.getParent() != null)
cc = cc.getParent();
//System.out.println("Parent:" + _cc);
if (_cc instanceof TradeDetailForm)
return _cc;
return null;
public void focusLost(java.awt.event.FocusEvent event)
Begin Nirmal 1: Requirements 3.1 issues.
To fix: getValue() method never returns more than the rows.
New method added to ensure user entered text never goes beyond Rows
* Method to ensure the getValue() never returns more than the rows.
* will return -1 if the rows are out of range
* @param KeyEvent
* @return int
public int ensureNotBeyondRows(KeyEvent e)
String[] s = getValue();
if (s==null)
return 0;
if (s.length>rows)
setText(retainText);
return -1;
String str=getText();
insert(e.getKeyChar()+"", getCaretPosition());
s = getValue();
setText(str);
if (s.length>rows)
setText(retainText);
return -1;
return 0;
End Nirmal 1:
// main Method
// processComponentKeyEvent Method
public void keyTyped(KeyEvent e)
/* Naga */
System.out.println("inside keyTyped");
System.out.println("e.getKeyChar() " + KeyEvent.getKeyText(e.getKeyCode()));
/*try
java.lang.Thread.sleep(2000);
catch(InterruptedException ie)
try {
int curPos2 = getCaretPosition();
int curLine2 = getLineOfOffset(curPos2);
//System.out.println( "curline:" + curLine2 + " of " + rows);
char[] tmp = {e.getKeyChar()};
int curPos1 = getCaretPosition();
int line1 = getLineOfOffset(curPos1) ;
int startOfLine = getLineStartOffset(line1) ;
if( curPos1 == startOfLine && line1 > 0)
if ((tmp[0] == ':') || (tmp[0] == '-' )){
// System.out.println("hman3");
e.consume();
return;
Begin Nirmal 2: Requirements 3.1 issues.
To fix: getValue() method never returns more than the rows.
New method added to ensure user entered text never goes beyond Rows
if (!isArrowKey(e) &&
(e.paramString().indexOf("Enter") == -1 ) &&
!isBackspaceKey(e)) {
int maxLimitFlg=ensureNotBeyondRows(e);
setCaretPosition(curPos2);
if (maxLimitFlg == -1)
e.consume();
return;
End Nirmal 2:
// System.out.println("e.paramString()" + e.paramString());
// System.out.println("place 2 " + e.paramString());
if (!(StringFormatter.isValidSwift(tmp[0])) && !(functionKey(e)) && notMoveForward(e))
// System.out.println("hman2 isaction" + e.isActionKey());
// System.out.println("KeyTyped" + e.getKeyChar()+ e.getKeyText(e.getKeyCode()) + "/keycode" + e.getKeyCode() + "/modifiers" + e.getModifiers() );
e.consume();
return;
int curPosInLine = -1;
int firstPos = -1;
if (getText().length() < maxTextAllowed ||
(KeyCode == KeyEvent.VK_UP || KeyCode == KeyEvent.VK_BACK_SPACE))
int curPos = getCaretPosition();
if (!(functionKey(e)))
e.setKeyChar( (new String( tmp ).toUpperCase()).toCharArray()[0]);
curPos2 = getCaretPosition();
curLine2 = getLineOfOffset(curPos2);
//System.out.println( "curline:" + curLine2 + " of " + rows);
if (curLine2 + 1 >= rows &&
(KeyCode == KeyEvent.VK_ENTER ||
KeyCode == KeyEvent.VK_DOWN) )
// System.out.println("hman1");
e.consume();
return;
else {
String oldText = getText();
// super.processKeyEvent(e);
if (getNumberOfLines(getLineCount()) == -1 && !(functionKey(e)))
setText(oldText);
invalidate();
setCaretPosition(curPos);
} } catch (javax.swing.text.BadLocationException evt) {
System.out.println("Bad Location Exception in processKeyEvent");
public void keyPressed(KeyEvent e){
//System.out.println("keyPressed" + e.getKeyCode()+ e.getKeyText(e.getKeyCode()));
retainText = getText();//retain always the latest text
/* Naga */
//System.out.println("retainText " + retainText);
System.out.println("inside keyPressed");
System.out.println("e.getKeyChar() " + KeyEvent.getKeyText(e.getKeyCode()));
/*try
java.lang.Thread.sleep(2000);
catch(InterruptedException ie)
public void keyReleased(KeyEvent e){
//System.out.println( "keyReleased" + e.getKeyCode()+ e.getKeyText(e.getKeyCode()));
String []s = getValue();
/* Naga */
System.out.println(" inside keyReleased");
System.out.println("e.getKeyChar() " + KeyEvent.getKeyText(e.getKeyCode()));
/*try
java.lang.Thread.sleep(2000);
catch(InterruptedException ie)
/*try
System.out.println("s " + s[0]);
System.out.println("s " + s[1]);
System.out.println("s " + s[2]);
System.out.println("s " + s[3]);
catch(Exception e1)
//System.out.println("s.length " + s.length);
//System.out.println("rows " + rows);
if (s!=null && s.length>rows)
System.out.println("setting text");
//setText(retainText);
invalidate();
public boolean isTab(KeyEvent e)
if (e.paramString().indexOf("keyChar=Tab") == -1)
return false;
} else
return true;
public boolean keepProcessing(java.awt.event.KeyEvent e)
if (e.paramString().indexOf("keyChar=Backspace") != -1 ) { return true; }
if (e.paramString().indexOf("keyChar=Left") != -1 ) { return true; }
if (e.paramString().indexOf("keyChar=Down") != -1 ) { return true; }
if (e.paramString().indexOf("keyChar=Up") != -1 ) { return true; }
if (e.paramString().indexOf("keyChar=Delete") != -1 ) { return true; }
if (e.paramString().indexOf("keyChar=Right") != -1 ) { return true; }
return false;
public boolean isArrowKey(java.awt.event.KeyEvent e)
if (e.paramString().indexOf("Left") != -1 ||
e.paramString().indexOf("Down") != -1 ||
e.paramString().indexOf("Up") != -1 ||
e.paramString().indexOf("Right") != -1 )
return true;
return false;
public boolean isBackspaceKey(java.awt.event.KeyEvent e)
if (e.paramString().indexOf("Backspace") != -1)
return true;
return false;
public boolean isDeleteKey(java.awt.event.KeyEvent e)
if (e.paramString().indexOf("Delete") != -1)
return true;
return false;
public boolean notMoveForward(java.awt.event.KeyEvent e)
if (e.paramString().indexOf("Backspace") == -1 &&
e.paramString().indexOf("Left") == -1 &&
// e.paramString().indexOf("keyText=Down") == -1 &&
e.paramString().indexOf("Up") == -1 &&
e.paramString().indexOf("Delete") == -1 ) { return true; }
return false;
// processKeyEvent Method
public void processKeyEvent(java.awt.event.KeyEvent e)
// System.out.println( "processKeyEvent");
/* Naga */
System.out.println(" inside processKeyEvent");
System.out.println("e.getKeyChar() " + KeyEvent.getKeyText(e.getKeyCode()));
if (e.paramString().indexOf("KEY_PRESSED") != -1) {
KeyText=e.paramString();
} else {
KeyText="";
KeyCode=e.getKeyCode();
int filledRows = (getText().length()-1)/columns + 1;
if (KeyCode == KeyEvent.VK_ENTER && filledRows >= rows)
return;
try {
if (isArrowKey(e) || isBackspaceKey(e) || isDeleteKey(e)) {
super.processKeyEvent(e);
return;
int curPos2 = getCaretPosition();
int curLine2 = getLineOfOffset(curPos2);
// System.out.println( "curline:" + curLine2 + " of " + rows);
if (curLine2 + 1 >= rows &&
(KeyCode == KeyEvent.VK_ENTER ||
KeyCode == KeyEvent.VK_DOWN) )
//System.out.println("hman5");
e.consume();
return;
int curPosInLine = -1;
int firstPos = -1;
if (getText().length() < maxTextAllowed)
int curPos = getCaretPosition();
curPos2 = getCaretPosition();
curLine2 = getLineOfOffset(curPos2);
int curlinepos = getLineStartOffset(curLine2) ;
if ( (curLine2 + 1 == rows) && (curPos2 - curlinepos >= getColumns() - 1) && notMoveForward(e))
e.consume();
return;
if ((curLine2 + 1 >= rows &&
(KeyCode == KeyEvent.VK_ENTER ||
KeyCode == KeyEvent.VK_DOWN) ))
// System.out.println("hman6");
e.consume();
return;
} else {
String oldText = getText();
// System.out.println("hman7");
super.processKeyEvent(e);
if (getNumberOfLines(getLineCount()) == -1 && !(functionKey(e)))
// System.out.println("hman8");
setText(oldText);
invalidate();
setCaretPosition(curPos);
} } catch (javax.swing.text.BadLocationException evt) {
System.out.println("Bad Location Exception in processKeyEvent");
// processFunctionalKeys Method
public boolean processFunctionalKeys(java.awt.event.KeyEvent e)
// System.out.println( "processFunctionalKeys");
if (KeyCode == KeyEvent.VK_BACK_SPACE ||
KeyCode == KeyEvent.VK_ESCAPE ||
KeyCode == KeyEvent.VK_PAGE_UP ||
KeyCode == KeyEvent.VK_PAGE_DOWN ||
KeyCode == KeyEvent.VK_END ||
KeyCode == KeyEvent.VK_HOME ||
KeyCode == KeyEvent.VK_LEFT ||
KeyCode == KeyEvent.VK_UP ||
KeyCode == KeyEvent.VK_RIGHT ||
KeyCode == KeyEvent.VK_DOWN ||
KeyCode == KeyEvent.VK_DELETE
//System.out.println("Process the KEY getkey:" + e.getKeyChar() + "/getcode:" + e.getKeyCode());
super.processKeyEvent(e);
return true;
else
return false;
public boolean functionKey(java.awt.event.KeyEvent e)
// System.out.println( "functionKey");
if (KeyCode == KeyEvent.VK_BACK_SPACE ||
KeyCode == KeyEvent.VK_ESCAPE ||
KeyCode == KeyEvent.VK_PAGE_UP ||
KeyCode == KeyEvent.VK_PAGE_DOWN ||
KeyCode == KeyEvent.VK_END ||
KeyCode == KeyEvent.VK_HOME ||
KeyCode == KeyEvent.VK_LEFT ||
KeyCode == KeyEvent.VK_UP ||
KeyCode == KeyEvent.VK_RIGHT ||
KeyCode == KeyEvent.VK_DOWN ||
KeyCode == KeyEvent.VK_DELETE
//System.out.println("Process the KEY getkey:" + e.getKeyChar() + "/getcode:" + e.getKeyCode());
//super.processKeyEvent(e);
return true;
else
return false;
// getLineCount Method - Returns -1 if number of lines is not between 1 to 4.
/* This method return -1 if number of lines is not between 1 to 4.
Pass in getLineCount() to get number of lines for all elements.
JTextArea separates elements by new line character.
BnyTextArea treats each row as a line.
public int getNumberOfLines(int elementCount)
int lineCount = 0;
int startPos = 0;
int endPos = 0;
for (int i = 0; i <= elementCount - 1; i++) {
lineCount = lineCount + getLineCountOfElement(i);
if (lineCount == -1 || lineCount > rows) {
lineCount = -1;
break;
return lineCount;
// getSpacePos Method - this method finds the first position of space found.
public int getSpacePos(int pos)
Begin Nirmal 3: Requirements 3.1 issues.
Modified the end limit from 0 to pos-columns,
so that to avoid the return index value from previous lines
int endLimit=pos-columns;
if (endLimit<0) {
endLimit=pos;
for (int i = pos; i > endLimit; i--) {
if (getText().charAt(i) == ' ' || getText().charAt(i) == '\n') { // 11/14/03 Eaten treat \n as space
return i;
return -1;
End Nirmal 3:
// getLineCountOfElement Method - returns -1 if number of lines is not between 1 to 4.
public int getLineCountOfElement(int line)
int lineCount = 1;
try {
int startPos = getLineStartOffset(line) ;
int endPos = getLineEndOffset(line) ;
if (moreThanNumOfColumns(startPos, endPos)) {
lineCount = 2;
startPos = getSpacePos(startPos+columns);
if (startPos != -1 && moreThanNumOfColumns(startPos+1,endPos)) {
lineCount = 3;
startPos = getSpacePos(startPos+columns);
if (startPos != -1 && moreThanNumOfColumns(startPos+1,endPos)) {
lineCount = 4;
startPos = getSpacePos(startPos+columns);
if (startPos != -1 && moreThanNumOfColumns(startPos+1,endPos)) {
return -1;
} catch (javax.swing.text.BadLocationException e) {
System.out.println("Bad Location Exception in getLineCountOfElement");
return lineCount;
// moreThanNumOfColumns Method
public boolean moreThanNumOfColumns(int startPos, int endPos)
if ((endPos - startPos) > (columns + 1))
return true;
else
return false;
// getNewLineCount Method
public int getNewLineCount()
int count = 0;
boolean rc = true;
int pos = getText().indexOf(KeyEvent.VK_ENTER, 0);
if (pos == -1)
rc = false;
else
count++;
while (rc) {
pos = getText().indexOf(KeyEvent.VK_ENTER, pos+1);
if (pos == -1)
rc = false;
else
count++;
return count;
// getValue Method
public String[] getValue()
// System.out.println(getText());
int lines = getLineCount();
int spacePos = 0;
String str = new String();
Vector strings = new Vector();
boolean newLine=true;
/*Nirmal : this boolean is to add the empty only in new line.
To avoid those lines which end with \n
if (getDocument().getLength() > 0) {
for (int i = 0; i < lines; i++) {
newLine=true;
try {
int startPos = getLineStartOffset(i) ;
int endPos = getLineEndOffset(i) + 1;
/* Naga */
//System.out.println("startPos " + startPos);
//System.out.println("endPos " + endPos);
//System.out.println(i + "HHMAN startPos = " + getLineStartOffset(i));
//System.out.println(i + "HHMAN endPos = " + getLineEndOffset(i));
while (moreThanNumOfColumns(startPos,endPos)) {
newLine=false;
int tempEndPos = 0;
tempEndPos = startPos + columns;
System.out.println("tempEndPos " + tempEndPos + " columns " + columns);
spacePos = getSpacePos(tempEndPos);
if (spacePos == -1) {
if (startPos >= getDocument().getLength())
break;
else {
if (tempEndPos >= getDocument().getLength())
spacePos = getDocument().getLength();
else {
spacePos = startPos + columns;
str = getText().substring(startPos,spacePos);
if (!(str.trim().equals(""))) {
strings.addElement(str.trim());
startPos = spacePos;
if (startPos < endPos) {
str = getText().substring(startPos,endPos - 1).trim();
if(str!=null) {
if(str.trim().length()>0) {
strings.addElement(str);
continue;
} else {
if(newLine) {
strings.addElement(str);
/*Nirmal commented the below lines to fix existing issue
of adding even empty lines entered in textbox */
//if ((str==null) || (str.length()==0)) continue;
//if (!(str.trim().equals(""))) strings.addElement(str);
} catch (javax.swing.text.BadLocationException e) {
System.out.println("Bad Location Exception in getValue");
String[] strs = new String[strings.size()];
strings.copyInto(strs);
return strs;
} else
return null;
public void clear() {
setText("");
// invalidate();
// repaint();
// fixTAB();
public int getColumnsX()
if (columnLimits != null)
int curPos = getCaretPosition();
//System.out.println("getCaretPosition()" + curPos);
if (curPos > 0)
for (int i = 0;i < columnLimits.length;i++)
curPos = curPos - columnLimits[i];
if (curPos < 1)
//System.out.println("getNumberOfLines(curElem)" + i);
return columnLimits[i];
} else
return columns;
return 0;
public void setRowLimitX(int rows,int columns)
maxTextAllowed = rows * columns;
setRows(_rows);
rows = _rows;
columns = _columns;
setFont(fixedFont);
setBorder(new BevelBorder(BevelBorder.LOWERED));
setLineWrap(true);
setWrapStyleWord(true);
Font fixedFont = new Font("Courier", Font.PLAIN, 12);
FontMetrics fm = getFontMetrics(fixedFont);
int width = fm.charWidth('W') * (35 + 1);
int height = DEFAULT_LABEL_HEIGHT * 3 ;
setPreferredSize(new Dimension(width, height));
public void setEditable(boolean editable)
super.setEditable(editable);
super.setEnabled(editable);
setFocusable(editable);
if (editable)
setForeground(Color.black);
else
setForeground(Color.gray);
fixTAB();
// add your data members here
// add your data members here
private int rows = 0;
private int columns = 0;
private int[] columnLimits = null;
private int maxTextAllowed = 0;
private Font fixedFont = new Font("Courier", Font.PLAIN, 12);
public final static int LEFT_LABEL_WIDTH = 100;
public final static int DEFAULT_LABEL_HEIGHT = 20;You posted way too much code. 90% of the code is not related to the "backspace" problem. We want compileable and executable code, but only that code that is relevant to the problem.
Anyway, instead of handling KeyEvents you should read the Swing tutorial on [url http://java.sun.com/docs/books/tutorial/uiswing/misc/keybinding.html]How to Use Key Bindings for the recommended approach.
Also you may want to check out this posting which has some information on the backspace KeyStroke:
http://forum.java.sun.com/thread.jspa?forumID=57&threadID=566748 -
hey guys, im writing a program and I have a JScrollPane and i want to have multiple JTextFields and radio buttons in it that work with the scroll pane so you can type something in on lets say field 1 and then scroll down to field 15 and type something into that one. is this possible? so far ive gotten them to show up in the scroll pane but the scroll bar doesnt even appear. ive tried setting the policy to ALWAYS but that little scroll block doesnt appear, only the bar itself thus making any fields below the windows bounds unaccessable. Any idea how to get this working?
Message was edited by:
HDL_CinC_Dragonrun this the 3 times to see the differences
import javax.swing.*;
import java.awt.*;
class Testing extends JFrame
JPanel p = new JPanel(new GridLayout(0,1));
JScrollPane sp = new JScrollPane(p);
public Testing()
setSize(600,400);
setLocation(200,100);
setDefaultCloseOperation(EXIT_ON_CLOSE);
for(int x = 0; x < 50; x++)
p.add(new JLabel("Hello World"));
//sp.setPreferredSize(new Dimension(500,300));//test without this line, then with the line
JPanel p1 = new JPanel();
p1.add(sp);
getContentPane().add(p1);
getContentPane().add(sp);//comment out this line, uncomment above block
public static void main(String[] args){new Testing().setVisible(true);}
} -
Problem with JTextArea wanting to resize itself
First, here is a program that will create the situation in which this error occurs:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class Example extends JFrame
private final String TITLE = "Example";
private final int WIDTH = 640;
private final int HEIGHT = 480;
private JMenuBar menuBar = new JMenuBar();
private JMenu modeMenu = new JMenu( "Mode" );
private JMenuItem mode1 = new JMenuItem( "Mode 1" );
private JMenuItem mode2 = new JMenuItem( "Mode 2" );
private JTextArea textArea1 = new JTextArea();
private JTextArea textArea2 = new JTextArea();
private JScrollPane scrollPane1 = new JScrollPane( textArea1, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER );
private JScrollPane scrollPane2 = new JScrollPane( textArea2, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER );
private JPanel everything = new JPanel( new BorderLayout() );
private JPanel modeOptions = new JPanel();
private int modeInt = 1;
public Example ()
setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
setSize( WIDTH, HEIGHT );
setLocation( 100, 100 );
setResizable( true );
mode1.addActionListener( new ActionListener()
public void actionPerformed ( ActionEvent e )
modeInt = 1;
updateModeOptions();
mode2.addActionListener( new ActionListener()
public void actionPerformed ( ActionEvent e )
modeInt = 2;
updateModeOptions();
modeMenu.add( mode1 );
modeMenu.add( mode2 );
menuBar.add( modeMenu );
setJMenuBar( menuBar );
updateModeOptions();
initializeLayout();
private void updateModeOptions ()
modeOptions.removeAll();
switch ( modeInt )
case 1:
JLabel text = new JLabel( "Change to Mode 2 to see the text areas shrink." );
modeOptions.add( text );
setTitle( TITLE + " - " + "Mode 1" );
break;
case 2:
JPanel temp = new JPanel();
JLabel text = new JLabel( "Text in a JPanel, to show change in text area size." );
temp.add( text );
modeOptions.add( temp );
setTitle( TITLE + " - " + "Mode 2" );
break;
default:
break;
setVisible( true );
private void initializeLayout ()
JPanel panel1 = new JPanel( new BorderLayout() );
JPanel panel2 = new JPanel( new BorderLayout() );
JPanel everythingCenterPanel = new JPanel();
everything.setBorder( BorderFactory.createEtchedBorder() );
panel1.setBorder( BorderFactory.createTitledBorder( BorderFactory.createEtchedBorder(), "Scroll Pane 1" ) );
panel2.setBorder( BorderFactory.createTitledBorder( BorderFactory.createEtchedBorder(), "Scroll Pane 2" ) );
everythingCenterPanel.setLayout( new BoxLayout( everythingCenterPanel, BoxLayout.Y_AXIS ) );
panel1.add( scrollPane1 );
panel2.add( scrollPane2 );
everythingCenterPanel.add( panel1 );
everythingCenterPanel.add( modeOptions );
everythingCenterPanel.add( panel2 );
everything.add( everythingCenterPanel );
add( everything );
public static void main ( String[] args )
new Example().setVisible( true );
}Try changing between Mode 1 and Mode 2 (via the Mode menu) to see how the text areas resize as the object between them grows and shrinks. This behavior is correct.
What is incorrect is what happens when the user enters a large amount of text into one of the text boxes (6 or 7 lines of text should be enough to create the problem) and switches between modes.
I've tried using the getSize and setSize methods of various components at various points in the program but none seem to work effectively. The closest thing I've been able to do is to keep the JTextAreas, the JScrollPanes, and the JPanels holding them to remain the same sizes, but the text still pushes the panel between the JTextAreas down (and possibly out of) the window, leaving a blank area between the edge of the JPanel containing the JScrollPane and the JPanel in the center.
The JPanels containing the JScrollPanes must be able to resize correctly as the user resizes the window, so a constant size would not work in this situation.
Any help is greatly appreciated.What is incorrect is what happens when the user enters a large amount of text into one of the text boxes I don't notice anything happening when I add text to the text area. The scrollbars appear as is expected. The only difference for me when I switch between mode 1 and 2 is that the center panel changes in size slightly. This is because the panel is using a FlowLayout which by default has a 5 pixel vertical gap between each component. This is easily fixed by using:
JPanel temp = new JPanel( new FlowLayout(FlowLayout.CENTER, 5, 0) );I know you tested using JDK1.5 since I had to make the following change in order to get the example to work:
getContentPane().add( everything );
So maybe this is a version problem since I don't notice anything out of the ordinary other than what I already mentioned. -
Using JScrollBar with JTextArea
hey!
i'm using JDev 10g, creating a Swing Application
i have a JTextArea and a JScrollBar (both which I have dragged down from Component Palette)
how to I use JScrollBar with the JTextArea, such that the JScrollBar response to the JTextArea
help me out...
Cheers,
Shivekthis is the problem:
i have a JTextArea and a JScrollBar which I have "DRAGGED" down from the component pallette in JDev...
how do I make the JScrollBar work for the JTextArea... because right now the JTextArea is not responsing to the JScrollBar...
so when the text is flooded in the JTextArea, scrolling the JScrollBar doesnt work
this is my code:
private JTextArea jTextArea1 = new JTextArea();
private JScrollBar jScrollBar1 = new JScrollBar();
private void jbInit() throws Exception
this.getContentPane().add(jScrollBar1, null);
this.getContentPane().add(jTextArea1, null);
can u tell me wat code is missing! I've tried everything... read many tutorials some of them uses a panel...
cheers,
Shivek
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