Develop Reference

JFrame.repaint() and JFrame.revalidate() not working

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class TheSize extends JFrame implements ActionListener, KeyListener {
static String inText="";
JPanel pane=new JPanel();
JLabel word0=new JLabel("I would like my grid to be 2^",JLabel.RIGHT);
JLabel word1=new JLabel("* 2^ "+inText,JLabel.RIGHT);
JButton finish=new JButton("I'm done");
JTextField size=new JTextField("",3);
public TheSize(){
super("size");
System.out.println("hi");
setLookAndFeel();
setSize(550,100);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
FlowLayout box=new FlowLayout();
setLayout(box);
pane.add(word0);
pane.add(size);
pane.add(word1);
pane.add(finish);
finish.addActionListener(this);
add(pane);
setVisible(true);
pack();
size. addKeyListener(this);
setFocusable(true);
}
private void setLookAndFeel() {
try {
UIManager.setLookAndFeel(
"com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"
);
} catch (Exception exc) {
// ignore error
}
}
public void actionPerformed(ActionEvent e) {
}
#Override
public void keyPressed(KeyEvent arg0) {
}
#Override
public void keyReleased(KeyEvent arg0) {
}
#Override
public void keyTyped(KeyEvent e) {
inText=size.getText();
pane.revalidate();
pane.repaint();
}
public static void main(String[] args){
new TheSize();
}
}
a couple of things
I made sure the KeyListener is working, and it is not working as in no output, it didn't give me any error.
What should happen:
It should pop a frame which says I would like my grid to be 2^__(user input Textfield)____* 2^(what is in the textfield). (Button for I'm done).
however, (what is in the textfield) remains empty after I type something into the text field. I checked whether the program heard my keystrokes using System.out.println();, and it is working, so the revalidate(); and repaint() commands must not be(I also tested it out by putting a System.out.println(); in my constructor. Thanks in advance

Never use a KeyListener on a JTextField. Get rid of the KeyListener and the JTextField should likely accept text just fine. Instead, if you want to register user input, use a DocumentListener if you just want the text but won't filter it, or a DocumentFilter if you need to filter the text before it is displayed. This sort of question has been asked many times on this site.
Also note that your JLabel will never change, even if you do use a DocumentListener since you call setText(...) on your word1 JLabel but never re-call this method. Just changing the String that the inText String variable refers to of course will not magically change the JLabel's displayed text.
Note, that I'm not sure what you mean by the replicate() command as I've not heard of this method. Do you mean revalidate() if so, please clarify.
For example:
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Window;
import java.awt.event.ActionEvent;
import javax.swing.*;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.BadLocationException;
// Avoid extending JFrames if at all possible.
// and only extend other components if needed.
#SuppressWarnings("serial")
public class TheSize2 extends JPanel {
private static final String FORMAT = "* 2^ %s";
private static final int PREF_W = 550;
private static final int PREF_H = 100;
private String inText = "";
private JLabel word0 = new JLabel("I would like my grid to be 2^", JLabel.RIGHT);
private JLabel word1 = new JLabel(String.format(FORMAT, inText), JLabel.RIGHT);
private JButton finish = new JButton("I'm done");
private JTextField size = new JTextField("", 3);
public TheSize2() {
finish.setAction(new FinishAction("I'm Done"));
size.getDocument().addDocumentListener(new SizeListener());
add(word0);
add(size);
add(word1);
add(finish);
}
#Override // make JPanel bigger
public Dimension getPreferredSize() {
Dimension superSz = super.getPreferredSize();
if (isPreferredSizeSet()) {
return superSz;
}
int prefW = Math.max(superSz.width, PREF_W);
int prefH = Math.max(superSz.height, PREF_H);
return new Dimension(prefW, prefH);
}
private class SizeListener implements DocumentListener {
private void textUpdated(DocumentEvent e) {
try {
inText = e.getDocument().getText(0, e.getDocument().getLength());
word1.setText(String.format(FORMAT, inText));
} catch (BadLocationException e1) {
e1.printStackTrace();
}
}
#Override
public void changedUpdate(DocumentEvent e) {
textUpdated(e);
}
#Override
public void insertUpdate(DocumentEvent e) {
textUpdated(e);
}
#Override
public void removeUpdate(DocumentEvent e) {
textUpdated(e);
}
}
private class FinishAction extends AbstractAction {
public FinishAction(String name) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
Component comp = (Component) e.getSource();
if (comp == null) {
return;
}
Window win = SwingUtilities.getWindowAncestor(comp);
if (win == null) {
return;
}
win.dispose();
}
}
private static void createAndShowGui() {
TheSize2 theSize2 = new TheSize2();
JFrame frame = new JFrame("The Size");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(theSize2);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

I found the solution with the help of Hovercraft Full Of Eels, all I missed was to re setSize. It is not the best solution, but it is simple enough for me to understand.
import javax.swing.*;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class TheSize extends JFrame implements ActionListener, KeyListener {
static String inText="";
JPanel pane=new JPanel();
JLabel word0=new JLabel("I would like my grid to be 2^",JLabel.RIGHT);
JLabel word1=new JLabel("* 2^ "+inText,JLabel.RIGHT);
JButton finish=new JButton("I'm done");
JTextField size=new JTextField("",3);
public TheSize(){
super("size");
setLookAndFeel();
setSize(550,100);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
FlowLayout box=new FlowLayout();
setLayout(box);
pane.add(word0);
pane.add(size);
pane.add(word1);
pane.add(finish);
finish.addActionListener(this);
add(pane);
setVisible(true);
pack();
size.addKeyListener(this);
setFocusable(true);
}
private void setLookAndFeel() {
try {
UIManager.setLookAndFeel(
"com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"
);
} catch (Exception exc) {
// ignore error
}
}
public void actionPerformed(ActionEvent e) {
}
public static void main(String[] args){
new TheSize();
}
#Override
public void keyPressed(KeyEvent arg0) {
}
#Override
public void keyReleased(KeyEvent arg0) {
inText=size.getText();
word1.setText("* 2^ "+inText);
pane.revalidate();
pane.repaint();
}
#Override
public void keyTyped(KeyEvent arg0) {
}
}

Paint Swing JButton as disabled

I want to display a normal JButton as disabled, without setting it to setEnabled(false)!
I just want to show that this button is not enabled, but if the user pushs the button it should call the actionlistener as normal.
So what I did is:
import java.awt.Graphics;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class SwingTests {
private static void createWindow() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
MyButton button = new MyButton("Press");
button.setEnabled(false);
panel.add(button);
frame.add(panel);
frame.setSize(200, 200);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createWindow();
}
});
}
}
class MyButton extends JButton {
private boolean enabled = false;
public MyButton(String text) {
super(text);
super.setEnabled(true);
}
#Override
protected void paintBorder(Graphics g) {
if (isEnabled())
super.paintBorder(g);
else
; // paint disabled button
}
#Override
protected void paintComponent(Graphics g) {
if (isEnabled())
super.paintComponent(g);
else
; // paint disabled button
}
#Override
public void setEnabled(boolean b) {
enabled = b;
}
#Override
public boolean isEnabled() {
return enabled;
}
}
I "just" need to know what to write in paintComponent(g) and paintBorder(g).

if it is disabled and a user pushs the button i display an alarm why this button is disabled!
If it looks disabled I am probably not going to push it in the first place. You could achieve this type of effect using tool tips.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JToggleButton;
import javax.swing.SwingUtilities;
public class TestGUI {
public TestGUI() {
JFrame frame = new JFrame();
final JButton button = new JButton("Press Me");
final JToggleButton enable = new JToggleButton("Enable / Disable");
enable.setSelected(true);
button.setToolTipText("Enabled");
enable.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
if (enable.isSelected()) {
button.setEnabled(true);
button.setToolTipText("Enabled");
} else {
button.setEnabled(false);
button.setToolTipText("Not Enabled");
}
}
});
frame.add(button, BorderLayout.CENTER);
frame.add(enable, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestGUI();
}
});
}
}

if it is disabled and a user pushs the button i display an alarm why this button is disabled!
Add a MouseListener to the button when it is disabled. Then you can handle the mouseClicked() event to display your "alarm".

How to select text fields using tab key in java

When I press tab key on the keyboard I want to select my text fields in above order.how to do that?

Try this example....
package com.Demo;
import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
#SuppressWarnings("serial")
public class TabTest extends JFrame {
public TabTest() {
initialize();
}
private void initialize() {
setSize(300, 300);
setTitle("JTextArea TAB DEMO");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
JTextField textField = new JTextField();
JPasswordField passwordField = new JPasswordField();
final JTextArea textArea = new JTextArea();
JScrollPane scrollPane = new JScrollPane(textArea);
//
// Add key listener to change the TAB behaviour in
// JTextArea to transfer focus to other component forward
// or backward.
//
textArea.addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_TAB) {
if (e.getModifiers() > 0) {
textArea.transferFocusBackward();
} else {
textArea.transferFocus();
}
e.consume();
}
}
});
getContentPane().add(textField, BorderLayout.NORTH);
getContentPane().add(scrollPane, BorderLayout.CENTER);
getContentPane().add(passwordField, BorderLayout.SOUTH);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TabTest().setVisible(true);
}
});
}
}

jTextField1.setNextFocusableComponent(jTextField2);
jTextField2.setNextFocusableComponent(jTextField3);
jTextField3.setNextFocusableComponent(jTextField4);
jTextField4.setNextFocusableComponent(jTextField5);
try this :)

Try this:
txtfld.addFocusListener(new FocusListener() {
#Override
public void focusGained(FocusEvent e) {
txtfld.setText("aaa");
}
#Override
public void focusLost(FocusEvent e) {
...
}
});
see more complete code.

How to handle Submit button of JFrame

I have a problem, I have been making a Swing application.
My question is about how to handle Jbutton like a JOptionPane, if it's possible?
I want handle all of the buttons similarly to JOptionpane button, but our message written in main function System.out.println("this line executes...how to prevent..");
This function is to display the message, until Jframe is visible.
Can anyone let me know how to prevent & how to handle button functionality? Especially when it executes further when I click the button.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.Border;
#SuppressWarnings("serial")
public class InputVerifierExample extends JPanel {
public static final Color WARNING_COLOR = Color.red;
private JTextField firstNameField = new JTextField(10);
private JTextField middleNameField = new JTextField(10);
private JTextField lastNameField = new JTextField(10);
JLabel name=new JLabel("Name:");
private JTextField[] nameFields = {
firstNameField,
middleNameField,
lastNameField };
private JLabel warningLabel = new JLabel(" ");
public InputVerifierExample() {
warningLabel.setOpaque(false);
JPanel namePanel = new JPanel();
namePanel.add(name);
MyInputVerifier verifier = new MyInputVerifier();
for (JTextField field : nameFields) {
field.setInputVerifier(verifier);
namePanel.add(field);
}
namePanel.add(new JButton(new SubmitBtnAction()));
setLayout(new BorderLayout());
add(namePanel, BorderLayout.CENTER);
warningLabel.setForeground(Color.red);
add(warningLabel, BorderLayout.NORTH);
}
private class SubmitBtnAction extends AbstractAction {
public SubmitBtnAction() {
super("Submit");
}
#Override
public void actionPerformed(ActionEvent e) {
// first check all fields aren't empty
for (JTextField field : nameFields) {
if (field.getText().trim().isEmpty()) {
return ; // return if empty
}
}
String name = "";
for (JTextField field : nameFields) {
name += field.getText() + " ";
field.setText("");
}
name = name.trim();
JOptionPane.showMessageDialog(InputVerifierExample.this, name, "Name Entered",
JOptionPane.INFORMATION_MESSAGE);
}
}
private class MyInputVerifier extends InputVerifier {
#Override
public boolean verify(JComponent input) {
JTextField field = (JTextField) input;
if (field.getText().trim().isEmpty()) {
warningLabel.setText("Please do not leave this field empty :"+name.getText());
warningLabel.setBackground(WARNING_COLOR);
//firstNameField.setText("sorry");
return false;
}
warningLabel.setText("");
warningLabel.setBackground(null);
return true;
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("InputVerifier Example");
frame.setSize(200, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new InputVerifierExample());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
createAndShowGui();
System.out.println("this line executes...how to prevent..");
}
}

Basically, you have something like this:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class TestButton {
protected void createAndShowGUI() {
JFrame frame = new JFrame("Test button");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton button = new JButton("Click me");
frame.add(button);
frame.setSize(200, 200);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TestButton().createAndShowGUI();
}
});
System.err.println("Executed once the button has been clicked");
}
}
And you want the line System.err.println("Executed once the button has been clicked"); to be executed when the button is pressed (which is not the case here above).
The solution is actually very simple: you move the code to execute after the button click in another method (see below the proceed() method) and you invoke that line from an ActionListener:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class TestButton {
protected void createAndShowGUI() {
JFrame frame = new JFrame("Test button");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton button = new JButton("Click me");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
proceed();
}
});
frame.add(button);
frame.setSize(200, 200);
frame.setVisible(true);
}
protected void proceed() {
System.err.println("Executed once the button has been clicked");
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TestButton().createAndShowGUI();
}
});
}
}

Well, the question is not very much clear,but from your comment,you dont want to do any thing till a JButton is clicked? Or you want to preform a task after clicking of a button?
If that is so, dont put your further code inside your main block, call a function from actionPerformed block.Something like this:
public void actionPerformed(ActionEvent e) {
// first check all fields aren't empty
for (JTextField field : nameFields) {
if (field.getText().trim().isEmpty()) {
return ; // return if empty
}
}
String name = "";
for (JTextField field : nameFields) {
name += field.getText() + " ";
field.setText("");
}
name = name.trim();
JOptionPane.showMessageDialog(InputVerifierExample.this, name, "Name Entered",
JOptionPane.INFORMATION_MESSAGE);
display();///////////this is the function containing further code
}
}
//this is display
public void display()
{
System.out.println("this line executes...how to prevent..");
}

how to make JDialog inactive

I want to make JDialog-based window inactive, so all controls apeared disabled (in grey color). setEnabled(false) just makes impossible to click any control, even close window. But nothing turns gray. Help please.
EDIT: Here is sample code.
import javax.swing.JButton;
import javax.swing.JDialog;
public class Analyzer extends JDialog{
public Analyzer() {
JButton but = new JButton("test");
setLayout(null);
but.setBounds(10,10,100,100);
add(but);
setSize( 200, 200);
setVisible(true);
setEnabled(false);
}
public static void main(String[] args) {
new Analyzer();
}
}

The two ways I know to do this, one where you disable the components of a dialog recursively, and the second where you disable the entire dialog (including ability to drag the dialog):
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class DisableEg extends JPanel {
public static final String DISABLE_DIALOG_COMPONENTS = "Disable Dialog Components";
public static final String ENABLE_DIALOG_COMPONENTS = "Enable Dialog Components";
public static final String DISABLE_DIALOG = "Disable Dialog";
public static final String ENABLE_DIALOG = "Enable Dialog";
private static final int LOC_SHIFT = 150;
private Analyzer analyzer;
public DisableEg(JFrame frame) {
analyzer = new Analyzer(frame);
analyzer.pack();
analyzer.setLocationRelativeTo(frame);
Point location = analyzer.getLocation();
location = new Point(location.x - LOC_SHIFT, location.y - LOC_SHIFT);
analyzer.setLocation(location);
analyzer.setVisible(true);
add(new JButton(new AbstractAction(DISABLE_DIALOG_COMPONENTS) {
#Override
public void actionPerformed(ActionEvent evt) {
AbstractButton btn = (AbstractButton) evt.getSource();
if (btn.getText().equals(DISABLE_DIALOG_COMPONENTS)) {
btn.setText(ENABLE_DIALOG_COMPONENTS);
analyzer.setComponentEnabled(false);
} else {
btn.setText(DISABLE_DIALOG_COMPONENTS);
analyzer.setComponentEnabled(true);
}
}
}));
add(new JButton(new AbstractAction(DISABLE_DIALOG) {
#Override
public void actionPerformed(ActionEvent evt) {
AbstractButton btn = (AbstractButton) evt.getSource();
if (btn.getText().equals(DISABLE_DIALOG)) {
btn.setText(ENABLE_DIALOG);
analyzer.setEnabled(false);
} else {
btn.setText(DISABLE_DIALOG);
analyzer.setEnabled(true);
}
}
}));
}
private static void createAndShowGui() {
JFrame frame = new JFrame("Disable Example");
DisableEg mainPanel = new DisableEg(frame);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class Analyzer extends JDialog {
public Analyzer(JFrame frame) {
super(frame, "Analyzer Dialog", false);
JButton but = new JButton("test");
setLayout(new FlowLayout());
add(but);
setPreferredSize(new Dimension(200, 200));
}
public void setComponentEnabled(boolean enabled) {
setComponentEnabled(enabled, getContentPane());
// !! if you have menus to disable, you may need instead
// setComponentEnabled(enabled, this); // !!
}
private void setComponentEnabled(boolean enabled, Component component) {
component.setEnabled(enabled);
if (component instanceof Container) {
Component[] components = ((Container) component).getComponents();
if (components != null && components.length > 0) {
for (Component heldComponent : components) {
setComponentEnabled(enabled, heldComponent);
}
}
}
}
}

The typical way to do this is to use a glassPane, but Java 7 introduced JLayer that should do the trick too.