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change JLabel of a panel depending on Jbutton of another panel in the same Jframe

I have constructed a class for the JPanel with several JButtons.Inside this class I want to construct another JPanel with JLabels that will change depending on the actionPerformed on the JButtons of the first JPanel.Finally, I want to add these 2 panels on the same Jframe. Can all these be done within the class of the first Panel?Otherwise, which is a better approach for this problem?

Yes, you can. One way you could accomplish this is with anonymous inner classes (saves keystrokes):
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
public class Foo {
JLabel one;
JLabel two;
public static void main(String[] args) {
(new Foo()).go();
}
public void go() {
JFrame frame = new JFrame("Test");
// Panel with buttons
JPanel buttonPanel = new JPanel();
JButton changeOne = new JButton("Change One");
changeOne.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
one.setText("New text for one");
}
}
buttonPanel.add(changeOne);
JButton changeTwo = new JButton("Change Two");
changeTwo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
two.setText("New text for two");
}
}
buttonPanel.add(changeTwo);
frame.add(buttonPanel, BorderLayout.NORTH);
// Panel with labels
JPanel labelPanel = new JLabel();
one = new JLabel("One");
labelPanel.add(one);
two = new JLabel("Two");
labelPanel.add(two);
// Set up the frame
frame.add(labelPanel, BorderLayout.SOUTH);
frame.setBounds(50, 50, 500, 500);
frame.setDefaultCloseAction(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}

Why JPanel.focusGaind and Lost don't work?

Please take a look at the following code (I've missed the imports purposely)
public class MainFrame extends JFrame {
private JPanel contentPane;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MainFrame frame = new MainFrame();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public MainFrame() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);
tabbedPane.setBounds(10, 11, 414, 240);
contentPane.add(tabbedPane);
JPanel panel = new JPanel();
panel.addFocusListener(new FocusListener() {
#Override
public void focusLost(FocusEvent arg0) {
System.out.println("lost");
// I want to do something here, if I reach here!
}
#Override
public void focusGained(FocusEvent arg0) {
System.out.println("gained");
// I want to do something here, if I reach here!
}
});
tabbedPane.addTab("New tab", null, panel, null);
JButton button = new JButton("New button");
panel.add(button);
JPanel panel_1 = new JPanel();
tabbedPane.addTab("New tab", null, panel_1, null);
JPanel panel_2 = new JPanel();
tabbedPane.addTab("New tab", null, panel_2, null);
}
}
I've created this class to test it and then add the onFocusListener in my main code, but it's not working the way I expect. Please tell what's wrong or is this the right EvenetListener at all?

JPanels are not focusable by default. If you ever wanted to use a FocusListener on them, you'd first have to change this property via setFocusable(true).
But even if you do this, a FocusListener is not what you want.
Instead I'd look to listen to the JTabbedPane's model for changes. It uses a SingleSelectionModel, and you can add a ChangeListener to this model, listen for changes, check the component that is currently being displayed and if your component, react.
You are using setBounds and null layouts, something that you will want to avoid doing if you are planning on creating and maintaining anything more than a toy Swing program.
Edit
For example:
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import javax.swing.*;
import javax.swing.event.*;
#SuppressWarnings("serial")
public class MainPanel extends JPanel {
private static final int PREF_W = 450;
private static final int PREF_H = 300;
private static final int GAP = 5;
private static final int TAB_COUNT = 5;
private JTabbedPane tabbedPane = new JTabbedPane();
public MainPanel() {
for (int i = 0; i < TAB_COUNT; i++) {
JPanel panel = new JPanel();
panel.add(new JButton("Button " + (i + 1)));
panel.setName("Panel " + (i + 1));
tabbedPane.add(panel.getName(), panel);
}
setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
setLayout(new BorderLayout());
add(tabbedPane, BorderLayout.CENTER);
tabbedPane.getModel().addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent evt) {
Component component = tabbedPane.getSelectedComponent();
System.out.println("Component Selected: " + component.getName());
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
private static void createAndShowGui() {
MainPanel mainPanel = new MainPanel();
JFrame frame = new JFrame("MainPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

JPanel is a lightweight container and it is not a Actionable component so it does not get focus events. It lets you add focus listener because of swing component hierarchy. In Order to get tab selected events you need to use JTabbedPane#addChangeListener.
Hope this helps.

Adding ScrollPane to JTextArea

I am working on a project for my college course. I was just wondering if anyone knew how to add a scrollBar to a JTextArea. At present I have the GUI laid out correctly, the only thing missing is the scroll bar.
This is what the GUI looks like. As you can see on the second TextArea I would like to add the Scrollbar.
This is my code where I create the pane. But nothing seems to happen... t2 is the JTextArea I want to add it to.
scroll = new JScrollPane(t2);
scroll.setBounds(10,60,780,500);
scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
Any help would be great, thanks!

The Scroll Bar comes when your text goes beyond the bounds of your view area. Don't use Absolute Positioning, for such a small talk at hand, always prefer Layout Managers, do read the first para of the first link, to know the advantage of using a Layout Manager.
What you simply need to do is use this thingy :
JTextArea msgArea = new JTextArea(10, 10);
msgArea.setWrapStyleWord(true);
msgArea.setLineWrap(true);
JScrollPane msgScroller = new JScrollPane();
msgScroller.setBorder(
BorderFactory.createTitledBorder("Messages"));
msgScroller.setViewportView(msgArea);
panelObject.add(msgScroller);
Here is a small program for your understanding :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class JTextAreaScroller
{
private JTextArea msgArea;
private JScrollPane msgScroller;
private JTextArea logArea;
private JScrollPane logScroller;
private JButton sendButton;
private JButton terminateButton;
private Timer timer;
private int counter = 0;
private String[] messages = {
"Hello there\n",
"How you doing ?\n",
"This is a very long text that might won't fit in a single line :-)\n",
"Okay just to occupy more space, it's another line.\n",
"Don't read too much of the messages, instead work on the solution.\n",
"Byee byee :-)\n",
"Cheers\n"
};
private ActionListener timerAction = new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
if (counter < messages.length)
msgArea.append(messages[counter++]);
else
counter = 0;
}
};
private void displayGUI()
{
JFrame frame = new JFrame("Chat Messenger Dummy");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setLayout(new BorderLayout(5, 5));
JPanel centerPanel = new JPanel();
centerPanel.setLayout(new GridLayout(0, 1, 5, 5));
logArea = new JTextArea(10, 10);
logArea.setWrapStyleWord(true);
logArea.setLineWrap(true);
logScroller = new JScrollPane();
logScroller.setBorder(
BorderFactory.createTitledBorder("Chat Log"));
logScroller.setViewportView(logArea);
msgArea = new JTextArea(10, 10);
msgArea.setWrapStyleWord(true);
msgArea.setLineWrap(true);
msgScroller = new JScrollPane();
msgScroller.setBorder(
BorderFactory.createTitledBorder("Messages"));
msgScroller.setViewportView(msgArea);
centerPanel.add(logScroller);
centerPanel.add(msgScroller);
JPanel bottomPanel = new JPanel();
terminateButton = new JButton("Terminate Session");
terminateButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
if (timer.isRunning())
timer.stop();
else
timer.start();
}
});
sendButton = new JButton("Send");
bottomPanel.add(terminateButton);
bottomPanel.add(sendButton);
contentPane.add(centerPanel, BorderLayout.CENTER);
contentPane.add(bottomPanel, BorderLayout.PAGE_END);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
timer = new Timer(1000, timerAction);
timer.start();
}
public static void main(String... args)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
new JTextAreaScroller().displayGUI();
}
});
}
}
Here is the outcome of the same :

The scroll bar by default will only be shown when the content overfills the available viewable area
You can change this via the JScrollPane#setVerticalScrollBarPolicy method, passing it ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS

how can I make this class an applet

I have the following class which is a simple gui, and I would like to make it an applet so it can be displayed in the browser. I know how to embed the code into an html page(got that done)... but how can make my class an applet? Also, I assuming I don't need a web server just to display the applet in my browser...
package tester1;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class PanelTest implements ActionListener {
JFrame frame;
JLabel inputLabel;
JLabel outputLabel;
JLabel outputHidden;
JTextField inputText;
JButton button;
JButton clear;
JButton about;
public PanelTest() {
frame = new JFrame("User Name");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(3, 2, 10, 10));
//creating first row
JPanel row1 = new JPanel();
inputLabel = new JLabel("Your Name");
inputText = new JTextField(15);
// FlowLayout flow1 = new FlowLayout(FlowLayout.CENTER, 10, 10);
// row1.setLayout(flow1);
row1.add(inputLabel);
row1.add(inputText);
frame.add(row1);
//creating second row
JPanel row2 = new JPanel();
button = new JButton("Display");
clear = new JButton("Clear");
about = new JButton("About");
button.addActionListener(this);
clear.addActionListener(this);
about.addActionListener(new displayAbout());
row2.add(button);
row2.add(clear);
row2.add(about);
frame.add(row2);
//creating third row
JPanel row3 = new JPanel();
outputLabel = new JLabel("Output:", JLabel.LEFT);
outputHidden = new JLabel("", JLabel.RIGHT);
// FlowLayout flow2 = new FlowLayout(FlowLayout.CENTER, 10, 10);
// row3.setLayout(flow2);
row3.add(outputLabel);
row3.add(outputHidden);
frame.add(row3);
frame.pack();
frame.setVisible(true);
}
//same method listen for two different events
#Override
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if(command.equals("Display")) {
outputHidden.setText(inputText.getText());
}
if(command.equals("Clear")) {
outputHidden.setText("");
inputText.setText("");
}
}
//another way to listen for events
class displayAbout implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(frame, "Username 1.1 \n by Jorge L. Vazquez");
}
}
public static void main(String[] args) {
PanelTest frameTest = new PanelTest();
}
}

Use a JApplet rather than a JFrame. Make sure you read the relevant Java Tutorial, which covers the applet lifecycle methods like init, start, stop, and destroy.
As a side note, you should not be building your UI outside of the event dispatch thread.

Use a JApplet instead of a JFrame like veer said, but you must also remove frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);, frame.pack();, and frame.setVisible(true);
Also, replace main(String[] args) with init().

Java swing 1.6 Textinput like firefox bar

I would like to create a textwidget/component wich looks like the firefox address bar. I mean a Textfield wich allows me to place little Buttons inside the field (e.g. cancel/reload/...)
I tried customizing a JLayeredPane, by creating a custom layout manager which maximizes the Textfield, and places the remainder from right to left. My problem is that this gave painting issues, I would not always see the items I added over the textfield. This might be Jython related, I try suppling java.lang.Integer(1) to the JLayeredPane.add. However the Layers are ordered exactly reverse to what the documentation says.
TO cricumvent this I derived my own JLayeredPane class and redefined paint to call paintComponents which in turn iterates over all components and calls their paint method, starting with the textbox, the rest thereafter.
However I don't always get the updates right away, meaning the buttons are hidden/only partly displayed and I can't Interact with the button.
What do I have to acutally see the update on screen (is it hidden in a buffer?))
How can I make it so that I can interact with the buttons?
How can I shorten the Texxtfield, so that the text starts scrolling to the front before I reach the end of the Textfield so that the text does not get hidden by the buttons? I still want the Textfields area to extend under the buttons
edit: the button is only displayed in the right place after i make the window smaller, after that it is also clickable
edit2:
I took the freedom to boil the answer down to this, which hides away a lot of that button code/unneccessary stuff
import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.*;
public class playground {
private Icon errorIcon = UIManager.getIcon("OptionPane.errorIcon");
private Icon infoIcon = UIManager.getIcon("OptionPane.informationIcon");
private Icon warnIcon = UIManager.getIcon("OptionPane.warningIcon");
public playground() {
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.add(makeButton(), BorderLayout.WEST);
JTextField text = new JTextField(20);
text.setBorder(null);
panel.add(text, BorderLayout.CENTER);
JPanel buttonsPanel = new JPanel();
buttonsPanel.setOpaque(false);
buttonsPanel.setLayout(new GridLayout(1, 2, 2, 2));
buttonsPanel.add(makeButton());
buttonsPanel.add(makeButton());
panel.add(buttonsPanel, BorderLayout.EAST);
panel.setBackground(text.getBackground());
JMenuBar menuBar = new JMenuBar();
menuBar.add(panel);
menuBar.add(Box.createHorizontalGlue());
JFrame frame = new JFrame("MenuGlueDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(menuBar);
frame.pack();
frame.setVisible(true);
}
public JToggleButton makeButton() {
final JToggleButton button = new JToggleButton();
button.setFocusable(false);
button.setMargin(new Insets(0, 0, 0, 0));
button.setContentAreaFilled(false);
button.setBorder(null);
button.setIcon((errorIcon));
button.setRolloverIcon((infoIcon));
button.setSelectedIcon(warnIcon);
button.setPressedIcon(warnIcon);
button.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
if (button.isSelected()) {
} else {
}
}
});
return button;
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
playground menuGlueDemo = new playground();
}
});
}
}

may be could it be simple by using JMenuBar, with Auto complete ComboBox / JFextField for example
import java.awt.ComponentOrientation;
import javax.swing.*;
public class MenuGlueDemo {
public MenuGlueDemo() {
JMenuBar menuBar = new JMenuBar();
menuBar.add(createMenu("Menu 1"));
menuBar.add(createMenu("Menu 2"));
menuBar.add(createMenu("Menu 3"));
menuBar.add(new JSeparator());
menuBar.add(new JButton(" Seach .... "));
menuBar.add(new JTextField(" Seach .... "));
menuBar.add(new JComboBox(new Object[]{"height", "length", "volume"}));
menuBar.add(Box.createHorizontalGlue());
menuBar.add(createMenu("About"));
JFrame frame = new JFrame("MenuGlueDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(menuBar);
frame.pack();
frame.setVisible(true);
}
public JMenu createMenu(String title) {
JMenu m = new JMenu(title);
m.add("Menu item #1 in " + title);
m.add("Menu item #2 in " + title);
m.add("Menu item #3 in " + title);
if (title.equals("About")) {
m.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
}
return m;
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
MenuGlueDemo menuGlueDemo = new MenuGlueDemo();
}
});
}
}
EDIT
I can simply but a text input and some buttons in a container with a proper layout and achieve [Textfield...] [B1] [B2] but I want [Textfield [B1] [B2]]
with proper LayoutManager
import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.*;
public class MenuGlueDemo {
private Icon errorIcon = UIManager.getIcon("OptionPane.errorIcon");
private Icon infoIcon = UIManager.getIcon("OptionPane.informationIcon");
private Icon warnIcon = UIManager.getIcon("OptionPane.warningIcon");
public MenuGlueDemo() {
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
JButton button = new JButton();
button.setFocusable(false);
//button.setMargin(new Insets(0, 0, 0, 0));
button.setContentAreaFilled(false);
button.setIcon((errorIcon));
button.setPressedIcon(warnIcon);
panel.add(button, BorderLayout.WEST);
JTextField text = new JTextField(20);
text.setBorder(null);
panel.add(text, BorderLayout.CENTER);
JPanel buttonsPanel = new JPanel();
buttonsPanel.setOpaque(false);
buttonsPanel.setLayout(new GridLayout(1, 2, 2, 2));
final JToggleButton toggleButton = new JToggleButton();
toggleButton.setFocusable(false);
toggleButton.setMargin(new Insets(0, 0, 0, 0));
toggleButton.setContentAreaFilled(false);
toggleButton.setIcon((errorIcon));
toggleButton.setRolloverIcon((infoIcon));
toggleButton.setSelectedIcon(warnIcon);
toggleButton.setPressedIcon(warnIcon);
toggleButton.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
if (toggleButton.isSelected()) {
} else {
}
}
});
buttonsPanel.add(toggleButton);
final JToggleButton toggleButton1 = new JToggleButton();
toggleButton1.setFocusable(false);
toggleButton1.setMargin(new Insets(0, 0, 0, 0));
toggleButton1.setContentAreaFilled(false);
toggleButton1.setIcon((errorIcon));
toggleButton1.setRolloverIcon((infoIcon));
toggleButton1.setSelectedIcon(warnIcon);
toggleButton1.setPressedIcon(warnIcon);
toggleButton1.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
if (toggleButton1.isSelected()) {
} else {
}
}
});
buttonsPanel.add(toggleButton1);
panel.add(buttonsPanel, BorderLayout.EAST);
panel.setBackground(text.getBackground());
JMenuBar menuBar = new JMenuBar();
menuBar.add(createMenu("Menu 1"));
menuBar.add(createMenu("Menu 2"));
menuBar.add(createMenu("Menu 3"));
menuBar.add(new JSeparator());
menuBar.add(new JButton(" Seach .... "));
menuBar.add(panel);
menuBar.add(new JComboBox(new Object[]{"height", "length", "volume"}));
menuBar.add(Box.createHorizontalGlue());
menuBar.add(createMenu("About"));
JFrame frame = new JFrame("MenuGlueDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(menuBar);
frame.pack();
frame.setVisible(true);
}
private JMenu createMenu(String title) {
JMenu m = new JMenu(title);
m.add("Menu item #1 in " + title);
m.add("Menu item #2 in " + title);
m.add("Menu item #3 in " + title);
if (title.equals("About")) {
m.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
}
return m;
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
MenuGlueDemo menuGlueDemo = new MenuGlueDemo();
}
});
}
}

You may be able to adapt the approach shown in Component Border, which allows "a JTextField and a JButton to work together." The related article Text Prompt may also prove useful. Finally, consider JToolBar, illustrated here, as a flexible way to tie components together.