I have a class whitch extends JPanel:
public class ButtonPanel extends JPanel {
private label;
public ButtonPanel() {
label=new JLabel("waiting for click");
add(label);
}
public void setButtonText() {
label.setText("just clicked");
}
}
I have several instances of that class which is added to JFrame. I want to create one instanse of MouseAdapter class and then add them as a mouse listener to all of the ButtonPanel components on my JFrame. I meen:
ButtonPanel butt1 = new ButtonPanel();
ButtonPanel butt2 = new ButtonPanel();
ButtonPanel butt3 = new ButtonPanel();
//... here goes code which add ButtonPanels to JFrame
MouseAdapterMod mam = new MouseAdapterMod();
butt1.addMouseListener(mam);
butt2.addMouseListener(mam);
butt3.addMouseListener(mam);
The MouseAdapterMod class I want to be separate from the other and locate in it's own package. It should looks like this:
public class MouseAdapterMod extends MouseAdapter {
public void mouseClicked(MouseEvent e) {
//here goes the code of calling setButtonText method of ButtonPanel component on which the event had occurred
}
}
So the problem is that I don't know how to implement mouseClicked method to make it determine which of ButtonPanel generate the event and call the corresponding to that component setButtonText() method. Is anyone know how to do that?
I know that I can achieve this by including event handling functionality in the ButtonPanel class, but thats not appropriate way for me, cuz I want to keep the class structure as I described above and have only one instance of MouseAdapterMod class for handling all of the ButtonPanels.
The MouseEvent#getSource method will return which object has been clicked:
public class MouseAdapterMod extends MouseAdapter {
// usually better off with mousePressed rather than clicked
public void mousePressed(MouseEvent e) {
ButtonPanel btnPanel = (ButtonPanel)e.getSource();
btnPanel.setButtonText();
}
}
As the comments note, you're often better off listening for mousePressed or mouseReleased rather than mouseClicked because for mouseClicked to work, the press and release must be from the same point, and if the mouse shifts even a slight amount, the click won't register.
My test program:
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.*;
public class MainForButtonPanel extends JPanel {
public MainForButtonPanel() {
setLayout(new GridLayout(4, 4));
MouseAdapter myMA = new MouseAdapterMod();
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
ButtonPanel btnPanel = new ButtonPanel();
btnPanel.addMouseListener(myMA);
add(btnPanel);
}
}
}
private static void createAndShowUI() {
JFrame frame = new JFrame("MainForButtonPanel");
frame.getContentPane().add(new MainForButtonPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
class ButtonPanel extends JPanel {
private static final int TIMER_DELAY = 2000;
private static final String JUST_CLICKED = "just clicked";
private static final String WAITING_FOR_CLICK = "waiting for click";
private static final Color CLICKED_COLOR = Color.pink;
private JLabel label;
public ButtonPanel() {
label = new JLabel(WAITING_FOR_CLICK);
add(label);
}
public void setButtonText() {
label.setText(JUST_CLICKED);
setBackground(CLICKED_COLOR);
new Timer(TIMER_DELAY, new ActionListener() {
public void actionPerformed(ActionEvent ae) {
label.setText(WAITING_FOR_CLICK);
setBackground(null);
((Timer)ae.getSource()).stop();
}
}).start();
}
}
class MouseAdapterMod extends MouseAdapter {
// usually better off with mousePressed rather than clicked
public void mousePressed(MouseEvent e) {
ButtonPanel btnPanel = (ButtonPanel)e.getSource();
btnPanel.setButtonText();
}
}
Related
I am trying to get the class i added to JPanel and run a function within the class.
I created MyButton class that extends JButton, This class i added to JPanel but after i added this class i want to run getText() on this objects.
I tried this but it does not recognize the function:
panel.getComponent(1).getText();
Main
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel(new GridLayout(2, 5));
for (int i = 0; i < 10; i++) {
panel.add(new MyButton());
}
frame.add(panel);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
MyButton
public class MyButton extends JButton {
private String text;
public MyButton()
{
this.text="Hello";
setText("test");
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
}
panel.getComponent(1).getText();
This returns a Component, which has no getText() method. It needs to be cast back to a JButton in order to use that method.
import java.awt.*;
import javax.swing.*;
public class ButtonText {
public static void main(String[] args) {
Runnable r = () -> {
JFrame frame = new JFrame();
JPanel panel = new JPanel(new GridLayout(2, 5));
for (int i = 0; i < 10; i++) {
panel.add(new JButton("Text " + (i+1)));
}
frame.add(panel);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
Component[] components = panel.getComponents();
for (Component component : components) {
JButton b = (JButton) component;
System.out.println(b.getText());
}
};
EventQueue.invokeLater(r);
}
}
BTW - having to trawl back though a panel to get the components seems like a poor hack. See What is the XY problem? Whatever the actual goal is here (& what is that goal?) is likely better served by storing the buttons in an array or list structure, when created.
i want to add panel from "newWork" class on pressing of "drop" button in "menuPan" class.
i cant add panel.
simply how to add Panel from different class on pressing button.
here are the three different classes .
MainClass :-
public class userFrame extends JFrame{
public void Frame()
{
setTitle("TEST CASE");
setSize(900,670);
add(new MenuPan(),BorderLayout.NORTH);
add(new WorkPan(),BorderLayout.CENTER);
setLocationRelativeTo(this);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String [] args){
userFrame u =new userFrame();
u.Frame();
}
}
MenuPan
public class MenuPan extends JPanel implements ActionListener{
WorkPan work=new WorkPan();
JButton view;
public menuPan() {
setBackground(Color.white);
setBorder(BorderFactory.createLineBorder(Color.LIGHT_GRAY));
setLayout(new FlowLayout(1, 15, 10));
view=new JButton(" Registered Courses ");
view.addActionListener(this);
add(view);
}
#Override
public void actionPerformed(ActionEvent e) {
work.TaskPannel();
}
}
WorkPAN class :-
class WorkPan extends JPanel{
JPanel work=new JPanel();
public WorkPan() {
setBackground(Color.LIGHT_GRAY);
setLayout(new BorderLayout(40, 50));
}
void TaskPannel() {
System.out.println("here");
add(new NewWork(),BorderLayout.CENTER);// adds NewWork panel
}
}
NewWork Class
class NewWork extends JPanel{
public NewWork(){
setBackground(Color.red);
}
}
One issue -- you create one workPan (which should be renamed WorkPan), change its state in your ActionListener, but never add it to your GUI. So you appear to be changing the state of a non-displayed GUI component, and so it would make sense that nothing will show in the GUI.
Suggestions:
Be sure to create only one WorkPan reference,
Be sure to display this single reference in the GUI
Be sure that your ActionListener calls the appropriate method on the same reference.
Side recommendation:
Learn and follow Java naming conventions so you others can more easily understand and follow your code.
To swap JPanels within a GUI, I strongly advise you to use a CardLayout rather than adding and removing components manually as you're currently doing. Please check out the CardLayout Tutorial.
And my solution does work, but you also must call revalidate and repaint to get the GUI to layout the new component and repaint it. Note additions and changes as marked by the \\ !! comment
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class FooWork {
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
userFrame.main(args);
});
}
}
class NewWork extends JPanel {
public NewWork() {
setBackground(Color.red);
}
}
class WorkPan extends JPanel {
JPanel work = new JPanel();
public WorkPan() {
setBackground(Color.LIGHT_GRAY);
setLayout(new BorderLayout(40, 50));
}
void TaskPannel() {
System.out.println("here");
add(new NewWork(), BorderLayout.CENTER);// adds NewWork panel
// !!
revalidate();
repaint();
// !!
}
}
class MenuPan extends JPanel implements ActionListener {
// !! WorkPan work = new WorkPan();
WorkPan work; // !!
JButton view; // !!
// !!
public MenuPan(WorkPan workPan) { // references are key
// !!
this.work = workPan; // set the reference!
// !!
setBackground(Color.white);
setBorder(BorderFactory.createLineBorder(Color.LIGHT_GRAY));
setLayout(new FlowLayout(1, 15, 10));
view = new JButton(" Registered Courses ");
view.addActionListener(this);
add(view);
}
#Override
public void actionPerformed(ActionEvent e) {
work.TaskPannel();
}
}
class userFrame extends JFrame {
public void Frame() {
setTitle("TEST CASE");
setSize(900, 670);
// !!
WorkPan workPan = new WorkPan();
MenuPan menuPan = new MenuPan(workPan);
// !!
// !!
// add(new MenuPan(), BorderLayout.NORTH);
// add(new WorkPan(), BorderLayout.CENTER);
add(menuPan, BorderLayout.NORTH);
add(workPan, BorderLayout.CENTER);
// !!
setLocationRelativeTo(this);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
userFrame u = new userFrame();
u.Frame();
}
}
But again, cleaner is to use a CardLayout to help with the swapping:
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.*;
public class SwapStuff {
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
private static void createAndShowGui() {
SwapMainPanel mainPanel = new SwapMainPanel();
JFrame frame = new JFrame("SwapStuff");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
}
class SwapMainPanel extends JPanel {
private CardLayout cardLayout = new CardLayout();
private JPanel cardPanel = new JPanel(cardLayout);
private ButtonPanel buttonPanel = new ButtonPanel(this); // pass the reference
private WorkPanel workPanel = new WorkPanel();
private ViewPanel viewPanel = new ViewPanel();
public SwapMainPanel() {
cardPanel.add(workPanel, workPanel.getClass().getName());
cardPanel.add(viewPanel, viewPanel.getClass().getName());
setLayout(new BorderLayout());
add(buttonPanel, BorderLayout.PAGE_START);
add(cardPanel, BorderLayout.CENTER);
}
// one possible way to swap "cards"
public void nextCard() {
cardLayout.next(cardPanel);
}
}
class ButtonPanel extends JPanel {
private SwapMainPanel mainPanel;
public ButtonPanel(SwapMainPanel mainPanel) {
this.mainPanel = mainPanel; // set the reference!
add(new JButton(new SwapAction("Swap Panels", KeyEvent.VK_S)));
}
private class SwapAction extends AbstractAction {
public SwapAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
mainPanel.nextCard();
}
}
}
class WorkPanel extends JPanel {
public WorkPanel() {
setBorder(BorderFactory.createTitledBorder("Work Panel"));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 400);
}
}
class ViewPanel extends JPanel {
public ViewPanel() {
setBorder(BorderFactory.createTitledBorder("View Panel"));
setBackground(Color.RED);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 400);
}
}
For architecture and design purposes I would like to design my GUI with a class for each card in a Java Swing CardLayout. and then have a mainapp that builds the GUI. I am having trouble doing this right now.
I would like to example have a class for the main menu with all the button locations etc. and then just instantiate that card and add it to the layout in another class. Does anyone know how to achieve this?
Perhaps you want to give your class that uses the CardLayout a public loadCard method, something like
public void loadCard(JComponent component, String key) {
cardHolderPanel.add(component, key);
}
where cardHolderPanel is the container that holds the cards.
Since your creating classes to act as cards, consider having them all extend from a base abstract class or an interface that has a method that allows this class to hold its own key String. Either that or simply use the JComponent name property to have a component hold its own key String, one that can easily be obtained via getName().
For a more detailed answer, you may need to give us more details on your current application and its structure.
very simple example that held Swing Objects generated from different Java Classes
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class OnTheFlyImageTest extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel cardPanel;
private CardLayout cardLayout;
public OnTheFlyImageTest() {
JPanel cp = new JPanel(new BorderLayout());
cp.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
cardLayout = new CardLayout(5, 5);
cardPanel = new JPanel(cardLayout);
cp.add(cardPanel);
for (int i = 0; i < 100; i++) {// Create random panels for testing.
String name = "ImagePanel" + (i + 1);
String image = (i & 1) == 0 ? "foo.gif" : "bar.gif";
ImagePanel imgPanel = new ImagePanel(name, image);
cardPanel.add(imgPanel, name);
cardLayout.addLayoutComponent(imgPanel, name);
}
JPanel buttonPanel = new JPanel(new GridLayout(1, 2, 5, 5));
JButton prevButton = new JButton("< Previous");
prevButton.setActionCommand("Previous");
prevButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
cardLayout.previous(cardPanel);
}
});
buttonPanel.add(prevButton);
JButton nextButton = new JButton("Next >");
nextButton.setActionCommand("Next");
nextButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
cardLayout.next(cardPanel);
}
});
buttonPanel.add(nextButton);
JPanel temp = new JPanel(new BorderLayout());
temp.add(buttonPanel, BorderLayout.LINE_END);
cp.add(temp, BorderLayout.SOUTH);
setContentPane(cp);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setTitle("Test");
pack();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new OnTheFlyImageTest().setVisible(true);
}
});
}
}
class ImagePanel extends JPanel {
private static final long serialVersionUID = 1L;
private String imgString;
private JLabel imgLabel;
public ImagePanel(String name, String imgString) {
setName(name);
this.imgString = imgString;
setLayout(new BorderLayout());
// Ensure size is correct even before any image is loaded.
setPreferredSize(new Dimension(640, 480));
}
#Override
public void setVisible(boolean visible) {
if (visible) {
System.err.println(getName() + ": Loading and adding image");
ImageIcon icon = new ImageIcon(imgString);
imgLabel = new JLabel(icon);
add(imgLabel);
}
super.setVisible(visible);
if (!visible) { // Do after super.setVisible() so image doesn't "disappear".
System.err.println(getName() + ": Removing image");
if (imgLabel != null) { // Before display, this will be null
remove(imgLabel);
imgLabel = null; // Hint to GC that component/image can be collected.
}
}
}
}
I have a button in a java frame that when pressed it reads a value from a text field and uses that string as a port name attempting to connect to a serial device.
If this connection is successful the method returns true if not it returns false. If it returns true I want the frame to disappear. A series of other frames specifed in other classes will then appear with options to control the serial device.
My problem is: the button is connected to an action listener, when pressed this method is invoked. If I try to use the frame.setVisible(true); method java throws a abstract button error because I'm effectively telling it to disappear the frame containing the button before the button press method has exited. Removing the frame.setVisible(true); allow the program to run correctly however I am left with a lingering connection frame that is no longer any use.
How to I get the frame to disappear upon pressing a the button?
package newimplementation1;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**
*
* #author Zac
*/
public class ConnectionFrame extends JPanel implements ActionListener {
private JTextField textField;
private JFrame frame;
private JButton connectButton;
private final static String newline = "\n";
public ConnectionFrame(){
super(new GridBagLayout());
textField = new JTextField(14);
textField.addActionListener(this);
textField.setText("/dev/ttyUSB0");
connectButton = new JButton("Connect");
//Add Components to this panel.
GridBagConstraints c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
c.fill = GridBagConstraints.HORIZONTAL;
add(textField, c);
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.0;
c.weighty = 1.0;
add(connectButton, c);
connectButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
boolean success = Main.mySerialTest.initialize(textField.getText());
if (success == false) {System.out.println("Could not connect"); return;}
frame.setVisible(false); // THIS DOES NOT WORK!!
JTextInputArea myInputArea = new JTextInputArea();
myInputArea.createAndShowGUI();
System.out.println("Connected");
}
});
}
public void actionPerformed(ActionEvent evt) {
// Unimplemented required for JPanel
}
public void createAndShowGUI() {
//Create and set up the window.
frame = new JFrame("Serial Port Query");
frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
//Add contents to the window.
frame.add(new ConnectionFrame());
frame.setLocation(300, 0);
//Display the window.
frame.pack();
frame.setVisible(true);
frame.addComponentListener(new ComponentAdapter() {
#Override
public void componentHidden(ComponentEvent e) {
System.out.println("Exiting Gracefully");
Main.mySerialTest.close();
((JFrame)(e.getComponent())).dispose();
System.exit(0);
}
});
}
}
Running your snippet (after removing/tweaking around the custom classes), throws an NPE. Reason is that the frame you'r accessing is null. And that's because it's never set. Better not rely on any field, let the button find its toplevel ancestor and hide that, like in
public void actionPerformed(final ActionEvent e) {
boolean success = true;
if (success == false) {
System.out.println("Could not connect");
return;
}
Window frame = SwingUtilities.windowForComponent((Component) e
.getSource());
frame.setVisible(false); //no problem :-)
}
Your problem is with this line:
frame.add(new ConnectionFrame());
You're creating a new ConnectionFrame object, and so the frame that your button tries to close on is not the same as the one being displayed, and this is the source of your problem.
If you change it to,
//!! frame.add(new ConnectionFrame());
frame.add(this);
so that the two JFrames are one and the same, things may work more smoothly.
But having said that, your whole design smells bad and I'd rethink it in a more OOP and less static fashion. Also, use dialogs where dialogs are needed, not frames, and rather than dialogs consider swapping views (JPanels) via CardLayout as a better option still.
Myself, I'd create a "dumb" GUI for this, one that creates a JPanel (here in my example it extends a JPanel for simplicity, but I'd avoid extending if not necessary), and I'd let whoever is calling this code decide what to do with the information via some control. For e.g.,
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class ConnectionPanel extends JPanel {
private JTextField textField;
private JButton connectButton;
private ConnectionPanelControl control;
public ConnectionPanel(final ConnectionPanelControl control) {
super(new GridBagLayout());
this.control = control;
ActionListener listener = new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (control != null) {
control.connectButtonAction();
}
}
};
textField = new JTextField(14);
textField.addActionListener(listener);
textField.setText("/dev/ttyUSB0");
connectButton = new JButton("Connect");
GridBagConstraints c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
c.fill = GridBagConstraints.HORIZONTAL;
add(textField, c);
c.fill = GridBagConstraints.BOTH;
c.weightx = 1.0;
c.weighty = 1.0;
add(connectButton, c);
connectButton.addActionListener(listener);
}
public String getFieldText() {
return textField.getText();
}
}
Again, something outside of the simple GUI would make decisions on what to do with the text that the textfield contains and what to do with the GUI that is displaying this JPanel:
public interface ConnectionPanelControl {
void connectButtonAction();
}
Also, you will likely do any connecting in a background thread so as to not freeze your GUI, probably a SwingWorker. Perhaps something like this:
import java.awt.event.ActionEvent;
import java.util.concurrent.ExecutionException;
import javax.swing.*;
#SuppressWarnings("serial")
public class MyMain extends JPanel {
public MyMain() {
add(new JButton(new ConnectionAction("Connect", this)));
}
private static void createAndShowGui() {
JFrame frame = new JFrame("My Main");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new MyMain());
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 ConnectionAction extends AbstractAction {
private MyMain myMain;
private ConnectionPanel cPanel = null;
private JDialog dialog = null;
public ConnectionAction(String title, MyMain myMain) {
super(title);
this.myMain = myMain;
}
#Override
public void actionPerformed(ActionEvent e) {
if (dialog == null) {
dialog = new JDialog(SwingUtilities.getWindowAncestor(myMain));
dialog.setTitle("Connect");
dialog.setModal(true);
cPanel = new ConnectionPanel(new ConnectionPanelControl() {
#Override
public void connectButtonAction() {
final String connectStr = cPanel.getFieldText();
new MySwingWorker(connectStr).execute();
}
});
dialog.getContentPane().add(cPanel);
dialog.pack();
dialog.setLocationRelativeTo(null);
}
dialog.setVisible(true);
}
private class MySwingWorker extends SwingWorker<Boolean, Void> {
private String connectStr = "";
public MySwingWorker(String connectStr) {
this.connectStr = connectStr;
}
#Override
protected Boolean doInBackground() throws Exception {
// TODO: make connection and then return a result
// right now making true if any text in the field
if (!connectStr.isEmpty()) {
return true;
}
return false;
}
#Override
protected void done() {
try {
boolean result = get();
if (result) {
System.out.println("connection successful");
dialog.dispose();
} else {
System.out.println("connection not successful");
}
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}
}
Your code would be much more readable if you named JFrame instances xxxFrame, and JPanel instances xxxPanel. Naming JPanel instances xxxFrame makes things very confusing.
It would also help if you pasted the stack trace of the exception.
I suspect the problem comes from the fact that frame is null. This is due to the fact that the frame field is only initialized in the createAndShowGUI method, but this method doesn't display the current connection panel, but a new one, which thus have a null frame field:
ConnectionFrame firstPanel = new ConnectionFrame();
// The firstPanel's frame field is null
firstPanel.createAndShowGUI();
// the firstPanel's frame field is now not null, but
// the above call opens a JFrame containing another, new ConnectionFrame,
// which has a null frame field
The code of createAndShowGUI should contain
frame.add(this);
rather than
frame.add(new ConnectionFrame());
for Swing GUI is better create only once JFrame and another Top-Level Containers would be JDialog or JWindow(un-decorated by default),
simple example here
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SuperConstructor extends JFrame {
private static final long serialVersionUID = 1L;
public SuperConstructor() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setPreferredSize(new Dimension(300, 300));
setTitle("Super constructor");
Container cp = getContentPane();
JButton b = new JButton("Show dialog");
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
FirstDialog firstDialog = new FirstDialog(SuperConstructor.this);
}
});
cp.add(b, BorderLayout.SOUTH);
JButton bClose = new JButton("Close");
bClose.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
System.exit(0);
}
});
add(bClose, BorderLayout.NORTH);
pack();
setVisible(true);
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
SuperConstructor superConstructor = new SuperConstructor();
}
});
}
private class FirstDialog extends JDialog {
private static final long serialVersionUID = 1L;
FirstDialog(final Frame parent) {
super(parent, "FirstDialog");
setPreferredSize(new Dimension(200, 200));
setLocationRelativeTo(parent);
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setModalityType(Dialog.ModalityType.DOCUMENT_MODAL);
JButton bNext = new JButton("Show next dialog");
bNext.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
SecondDialog secondDialog = new SecondDialog(parent, false);
}
});
add(bNext, BorderLayout.NORTH);
JButton bClose = new JButton("Close");
bClose.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
setVisible(false);
}
});
add(bClose, BorderLayout.SOUTH);
pack();
setVisible(true);
}
}
private int i;
private class SecondDialog extends JDialog {
private static final long serialVersionUID = 1L;
SecondDialog(final Frame parent, boolean modal) {
//super(parent); // Makes this dialog unfocusable as long as FirstDialog is visible
setPreferredSize(new Dimension(200, 200));
setLocation(300, 50);
setModal(modal);
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
setTitle("SecondDialog " + (i++));
JButton bClose = new JButton("Close");
bClose.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
setVisible(false);
}
});
add(bClose, BorderLayout.SOUTH);
pack();
setVisible(true);
}
}
}
better would be re-use Top-Level Containers, as create lots of Top-Level Containers on Runtime (possible memory lack)
I have a JFrame which contains 3 JPanels. I want to pass the JTextField value of one panel to other. Each panel is shown using JTabbedPane. I am getting null when i access the value of other text field. How can i access?
You don't show any code, and so it's impossible to know why you're getting "null" values. Two possible solutions if you want all three JPanels to hold JTextFields with the same content:
Put the shared JTextField outside of the JPanels held by the JTabbedPane and instead in a JPanel that holds the JTabbedPane, so that the field is always visible no matter what tab is displayed, or
Use several JTextFields but have them share the same Document or "model".
e.g.,
import java.awt.Dimension;
import javax.swing.*;
import javax.swing.text.PlainDocument;
public class SharedField extends JTabbedPane {
private static final int TAB_COUNT = 5;
private static final int MY_WIDTH = 600;
private static final int MY_HEIGHT = 300;
PlainDocument doc = new PlainDocument();
public SharedField() {
for (int i = 0; i < TAB_COUNT; i++) {
JTextField tField = new JTextField(10);
tField.setDocument(doc);
JPanel panel = new JPanel();
panel.add(tField);
add("Panel " + i, panel);
// to demonstrate some of the JTextFields acting like
// a label
if (i % 2 == 1) { // if i is odd
tField.setEditable(false);
tField.setBorder(null);
}
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(MY_WIDTH, MY_HEIGHT);
}
private static void createAndShowUI() {
JFrame frame = new JFrame("SharedField");
frame.getContentPane().add(new SharedField());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
Edit 1
I see that you've cross-posted this on java-forums.org/ where you show some of your code:
pacage Demotool;
Class:MainFrame
This is the actionPerformed code of first panel
both str and scrTxt is (public static)
public void actionPerformed(ActionEvent e)
{
String act=e.getActionCommand();
if(act.equals("ADD"))
{
str=scrnTxt.getText();
System.out.println("Hi :"+str);
Demotool.DemoTool.jtp.setSelectedIndex(1);
}
}
using the belove code i tried to access the data but I am getting null String:
System.out.println("Hello:"+Demotool.MainFrame.str);
Problems:
Don't use static variables or methods unless you have a good reason to do so. Here you don't.
You're may be trying to access the MainFrame.str variable before anything has been put into it, making it null, or you are creating a new MainFrame object in your second class, one that isn't displayed, and thus one whose str variable is empty or null -- hard to say.
Either way, this design is not good. You're better off showing us a small demo program that shows your problem with code that compiles and runs, an sscce, so we can play with and modify your code and better be able to show you a decent solution.
One such decent solution is to add a DocumentListener to the JTextField so that changes to the text held by the JTextField are "pushed" into the observers that are listening for changes (your other classes).
For example, using DocumentListeners:
import java.awt.Dimension;
import javax.swing.*;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.BadLocationException;
public class SharedField2 extends JTabbedPane {
private static final int LABEL_PANEL_COUNT = 4;
private static final int MY_WIDTH = 600;
private static final int MY_HEIGHT = 300;
public SharedField2() {
TextFieldPanel tfPanel = new TextFieldPanel();
LabelPanel[] labelPanels = new LabelPanel[LABEL_PANEL_COUNT];
add("TextFieldPanel", tfPanel);
for (int i = 0; i < labelPanels.length; i++) {
labelPanels[i] = new LabelPanel();
// add each label panel's listener to the text field
tfPanel.addDocumentListenerToField(labelPanels[i].getDocumentListener());
add("Label Panel " + i, labelPanels[i]);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(MY_WIDTH, MY_HEIGHT);
}
private static void createAndShowUI() {
JFrame frame = new JFrame("SharedField2");
frame.getContentPane().add(new SharedField2());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
class TextFieldPanel extends JPanel {
private JTextField tField = new JTextField(10);
public TextFieldPanel() {
add(tField);
}
public void addDocumentListenerToField(DocumentListener listener) {
tField.getDocument().addDocumentListener(listener);
}
}
class LabelPanel extends JPanel {
private DocumentListener myListener;
private JLabel label = new JLabel();
public LabelPanel() {
add(label);
myListener = new DocumentListener() {
#Override
public void changedUpdate(DocumentEvent e) {
updateLabel(e);
}
#Override
public void insertUpdate(DocumentEvent e) {
updateLabel(e);
}
#Override
public void removeUpdate(DocumentEvent e) {
updateLabel(e);
}
private void updateLabel(DocumentEvent e) {
try {
label.setText(e.getDocument().getText(0,
e.getDocument().getLength()));
} catch (BadLocationException e1) {
e1.printStackTrace();
}
}
};
}
public DocumentListener getDocumentListener() {
return myListener;
}
}
One simple solution will be making JTextField global so all panel can access it.
Make sure all your panel can access JTextField that is textField is globally accessible.
Following code demonstrate this:
JTextField textField = new JTextField(25);
JLabel labelForPanel2 = new JLabel(),labelForPanel3 = new JLabel();
private void panelDemo() {
JFrame frame = new JFrame();
frame.setSize(400, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel1 = new JPanel();
JPanel panel2 = new JPanel();
JPanel panel3 = new JPanel();
JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.addTab("Tab 1", panel1);
tabbedPane.addTab("Tab 2", panel2);
tabbedPane.addTab("Tab 3", panel3);
panel1.add(textField);
panel2.add(labelForPanel2);
panel3.add(labelForPanel3);
textField.addKeyListener(new KeyAdapter() {
#Override
public void keyReleased(KeyEvent e) {
labelForPanel2.setText(textField.getText());
labelForPanel3.setText(textField.getText());
}
});
frame.add(tabbedPane);
frame.setVisible(true);
}
I don't know what exactly are you going to achieve, but maybe try data binding?
Take a look at BetterBeansBinding library.