Develop Reference

Create a Method to add components in Selected JTabbedPane

I am a newbie, and I have already passed some days to get the idea, but could not solve it, if anyone can help me.
I have main two JPanel in one JFrame. I have some buttons in the first panel. I have One method to add a panel to theJTabbedPane by calling another method to create that JPanels then add it to the Tab.
I want a method which will add any buttons/components to the Selected tab which I want whenever I click the button from the first panel.
How can I do this. I can post those three method's code here if anyone wish to help me. Thanks in advance.
The first code add new tabs to the JTabbedPane,
private class TabPlus implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
JPanel panel = CreateSlice();
String title = "Slice " + String.valueOf(pane.getTabCount());
pane.insertTab(title, null, panel, null, pane.getTabCount() - 1);
}
}
The second code is for selecting the tabs,
private class TabSelect implements ChangeListener {
#Override
public void stateChanged(ChangeEvent e) {
JTabbedPane source = (JTabbedPane) e.getSource();
if (source.getSelectedComponent() != null) {
int index = source.getSelectedIndex();
System.out.print(index);
}
}
}
This creates the JPanel to be added to the JTabbedPane,
public JPanel CreateSlice() {
JPanel Slice = new JPanel();
Slice.setPreferredSize(new Dimension(550, 600));
return Slice;
}
The buttons are in another Panel with their own action.
GUI Image

You can add a panel with butttons this way:
public JPanel CreateSlice() {
JPanel Slice = new JPanel();
Slice.setPreferredSize(new Dimension(550, 600));
JPanel buttonsPanel = new JPanel();
buttonsPanel.add(new JButton("dumpButton"));
buttonsPanel.setVisible(false);
Slice.add(buttonsPanel);
return Slice;
}
And whenever a selection occurs set the visibility of buttonsPanel to true.

I think, I found one way to do this, My index variable int index = source.getSelectedIndex(); must be public variable, then in Action event of the buttons from another tab will add component to this selected JTabbedPane.
In my case I introduced and ArrayList of panel (network_slices), and every time I am adding a panel to the JTabbedPane, it is also adding to the ArrayList. then I called the panel from the ArrayList by using the index of selected JTabbedPane. Here is the part of the code.
private class TabSelect implements ChangeListener {
#Override
public void stateChanged(ChangeEvent e) {
JTabbedPane source = (JTabbedPane) e.getSource();
if (source.getSelectedComponent() != null) {
index = source.getSelectedIndex();
System.out.print(index);
}
}
}
private class AddTab implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
Slice panel = new Slice();
panel.setPreferredSize(new Dimension(550, 600));
String title = "Slice " + String.valueOf(pane.getTabCount());
pane.insertTab(title, null, panel, null, pane.getTabCount() - 1);
network_slices.add(panel);
}
}
private class AddNetworkFuncitons implements ActionListener {
public void actionPerformed(ActionEvent e) {
String buttonselected = (String) e.getActionCommand();
JButton button = new JButton(buttonselected);
network_slices.get(index).add(button).setVisible(true);
System.out.print(buttonselected);
}
}

JXTitledPanels in a JPanel a user needs to be able to choose one and click a remove button

I have a JPanel with n number of JXTitledPanels. The user should be able to click the JXTitledPanel and hit a remove button to remove it.
My question is how do I know what JXTitlePanel the user has selected.
here is a screen from my program basically I want a user to click "Hospitals", click remove and the Hospitals Table will disappear.

I'd probably add a "remove" control into the right decoration position. This way you could pass a reference to the control of the JXTiltedPane
titledPane.addRightDecoration(new MyRemoveControl(titkedPane));
Or such

#madprogrammer probably has the simplest answer, but if you don't want to change the look of the application, you could combine your button's actionListener with a mouseListener for the panels.
The mouseListener portion saves the last panel clicked, and the actionListener just removes the panel that was registered by the mouseListener.
Here's a quick sample I cooked up - it doesn't use JXTitledPane but that shouldn't matter because they're all in the same hierarchy.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TempProject extends JFrame{
public TempProject(){
Box mainContent = Box.createVerticalBox();
//Create Button
JButton removePanel = new JButton("RemovePanel");
RemoveListener listener = new RemoveListener(mainContent);
removePanel.addActionListener(listener);
mainContent.add(removePanel);
//Create Panels
mainContent.add(getPanel(Color.red, listener));
mainContent.add(getPanel(Color.orange, listener));
mainContent.add(getPanel(Color.pink, listener));
mainContent.add(getPanel(Color.magenta, listener));
setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
setContentPane(mainContent);
pack();
setVisible(true);
}
public JPanel getPanel(Color color, RemoveListener l){
JPanel result = new JPanel();
result.setBackground(color);
result.add(new JLabel(color.toString()));
result.addMouseListener(l);
return result;
}
public static void main(String args[])
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
new TempProject();
}
});
}
public static class RemoveListener extends MouseAdapter implements ActionListener{
Component lastSelectedComponent = null;
Container master; //The panel containing the ones being listened to
public RemoveListener(Container master){
this.master = master;
}
#Override
public void mouseClicked(MouseEvent arg0) {
lastSelectedComponent = (Component)arg0.getSource();
}
#Override
public void actionPerformed(ActionEvent e) {
if(lastSelectedComponent != null){
master.remove(lastSelectedComponent);
master.repaint();
}
}
}
}

Using AWT Buttons and detecting if clicked

I just joined, and am glad to be here~ So, this morning (at like 2am, but thats besides the point :P ) I was doing a little bit of Java tests with JFrame and other GUI stuff. This is my first time working with GUIs. I was trying to make a little java app that would act as a dream journaller. However, my progress was frozen when I encountered a problem i could not solve. My code is as follows.
import java.awt.*;
import javax.swing.*;
import java.applet.*;
public class Display extends Canvas
{
static final int WIDTH = 600;
static final int HEIGHT = 400;
public static String defaultEntry = "Dreams...";
public static final String TITLE = "Dream Journal Testing";
Button erase;
public static void main(String[] args)
{
Display d = new Display();
d.create();
}
public void create()
{
JFrame frame = new JFrame();
System.out.println("Running");
Panel cardOne = new Panel();
Panel p1 = new Panel();
Panel p2 = new Panel();
Panel p3 = new Panel();
Panel grid = new Panel();
cardOne.setLayout(new BorderLayout());
p1.setLayout(new GridLayout(2,1,3,6));
TextArea textArea1 = new TextArea(defaultEntry);
/*Font f1 = new Font("Courier", Font.PLAIN, 16);
setFont(f1);*/
Label l1 = new Label("Welcome to the Dream Journal! :)");
Label l2 = new Label("Type your dream below:");
p1.add(l1);
p1.add(l2);
p2.add(textArea1);
p3.setLayout(new FlowLayout(FlowLayout.CENTER));
Button ok = new Button("Save");
erase = new Button("Erase");
p3.add(erase);
p3.add(ok);
cardOne.add("North",p1);
cardOne.add("Center",p2);
cardOne.add("South",p3);
frame.add(cardOne);
//frame.add(cardOne);
//frame.setLocationRelativeTo(null);
frame.pack();
frame.setTitle(TITLE);
frame.setSize(WIDTH, HEIGHT);
frame.setResizable(false);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
System.out.println(textArea1.getText());
}
/*public boolean handleEvent(Event evt)
{
if(evt.target == erase)
{
System.out.println("it works");
return true;
}
else return super.handleEvent(evt);
}
*/
public boolean action(Event evt, Object arg)
{
if("Erase".equals(arg))
{
System.out.println("hello");
//textArea1.setText("");
}
return true;
}
}
The problem i have is I am not able to figure out how to make it so if the "Erase" AWT button is pushed, the system will print a line (as a test). I have tried
public boolean action(Event evt, Object arg)
And
public boolean handleEvent, but neither worked. Anyone have any suggestions for the Java noob that is me? Thanks!! :)

One way is to add an action listener to the button (e.g. for Save). Another way is to create an Action (e.g. for Erase).
Don't mix Swing with AWT components unless it is necessary. It is not worth even learning how to use AWT components at this point in time, use Swing only for best results and best help.
Here is a version of the app. using all Swing components.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Display
{
static final int WIDTH = 600;
static final int HEIGHT = 400;
public static String defaultEntry = "Dreams...";
public static final String TITLE = "Dream Journal Testing";
JButton erase;
public static void main(String[] args)
{
Display d = new Display();
d.create();
}
public void create()
{
JFrame frame = new JFrame();
System.out.println("Running");
JPanel cardOne = new JPanel();
JPanel p1 = new JPanel();
JPanel p2 = new JPanel();
JPanel p3 = new JPanel();
cardOne.setLayout(new BorderLayout());
p1.setLayout(new GridLayout(2,1,3,6));
JTextArea textArea1 = new JTextArea(defaultEntry);
JLabel l1 = new JLabel("Welcome to the Dream Journal! :)");
JLabel l2 = new JLabel("Type your dream below:");
p1.add(l1);
p1.add(l2);
p2.add(textArea1);
p3.setLayout(new FlowLayout(FlowLayout.CENTER));
JButton ok = new JButton("Save");
ok.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
System.out.println("Do " + ae.getActionCommand());
}
});
erase = new JButton(new EraseAction());
p3.add(erase);
p3.add(ok);
// Use the constants
cardOne.add(BorderLayout.PAGE_START,p1);
cardOne.add(BorderLayout.CENTER,p2);
cardOne.add(BorderLayout.PAGE_END,p3);
frame.add(cardOne);
frame.pack();
frame.setTitle(TITLE);
frame.setSize(WIDTH, HEIGHT);
frame.setResizable(false);
frame.setLocationByPlatform(true);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
System.out.println(textArea1.getText());
}
}
class EraseAction extends AbstractAction {
EraseAction() {
super("Erase");
}
#Override
public void actionPerformed(ActionEvent arg0) {
System.out.println("Do " + arg0.getActionCommand());
}
}

First let me explain you the Funda of Event Handler....
- First of all there are Event Source, when any action take place on the Event Source, an Event Object is thrown to the call back method.
- Call Back method is the method inside the Listener (Interface) which is needed to be implemented by the Class that implements this Listener.
- The statements inside this call back method will dictate whats needed to be done, when the action is done on the Event Source.
Eg:
Assume
Event Source - Button
When Clicked - Event object is thrown at the call back method
Call back method - actionPerformed(ActionEvent e) inside ActionListener.
Now your case :
Now this can be done in 2 ways.....
1. Let you Display class implements the ActionListener, then Register the button with
the ActionListener, and finally implement the abstract method actionPerformed() of ActionListener.
Eg:
public class Display extends Canvas implements ActionListener{
public Display(){
// Your code....
setComponent(); // Initializing the state of Components
}
public void setComponent(){
// Your code.........
Button b = new Button("Click");
b.addActionListener(this); // Registering the button.
// Your code..........
}
public void actionPerformed(ActionEvent event) {
// Do here whatever you want on the Button Click
}
}
2. Use Anonymous class.
- Anonymous class are declared and initialized simultaneously.
- Anonymous class must implement or extend to only one interface or class resp.
Your Display class will NOT implement ActionListener here....
public class Display extends Canvas {
public Display(){
// Your code....
setComponent(); // Initializing the state of Components
}
public void setComponent(){
// Your code.........
Button b = new Button("Click");
// Registering the button and Implementing it
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event) {
// Do here whatever you want on the Button Click
}
});
// Your code..........
}
}

You need to implement ActionListner :
public class Display extends Canvas implements ActionListener
and add yourself to your button as such:
erase.addActionListener(this);
and then implement the required method:
public void actionPerformed(ActionEvent event) {
//do stuff
}
For more info, check out this tutorial on creating ActionListeners.
You'll find that this observable pattern is widely used the in Java GUI.
A couple high level critiques:
You are using many older AWT components (ie Button) when there are similar, but newer (read: more flexible) Swing components available (ie JButton). Take a look at this for a quick explanation on the difference.
The event model that you have implemented was revamped in 1997 to the observable pattern that I suggested above. If you would like to learn more, you can read this.

Listening/Handling JPanel events

Good evening ladies and gentlemen,
I have a problem with Java Swing that I cannot solve, maybe you can help me. Here it is:
I have one JFrame which uses BorderLayout, and many JPanels.
Every time I need to put up a new screen (i.e. from the Main Menu, when Search button is clicked, go to the Search Menu), I simply remove the component (JPanel) which is located in the center, and put the new screen (new JPanel) in the center instead.
This way, I don't call all my header and footer objects every time I want to put up a new screen.
Everything works fine with this system except this little problem: I want to trigger some methods everytime I put up a new JPanel or change back to an existing JPanel (generally speaking, everytime a JPanel appears).
In order to do that, I tried to implement ComponentListener's componentShown(ComponentEvent e) method, and added a ComponentListener to a JPanel which I put up in the center of my JFrame, and it did NOT work. After this, I did some research and found out that this componentShown (#ComponentListener) method only works when the visibilty of the JPanel is changed (from invisible to visible or the opposite). Unfortunately, I'm not changing the visibility of a JPanel, just replacing it with another one: removing the current one, and adding the new one. Below code illustrates how I replace the JPanels.
// Get the JPanel located in the center of our JFrame
JPanel currentView = (JPanel) myFrame.getContentPane().getComponent( 2 );
if ( currentView != null )
{
// Remove it from the JPanel
myFrame.getContentPane().remove( currentView );
}
// Add the new JPanel
myFrame.getContentPane().add( otherView, BorderLayout.CENTER );
// Pack the JFrame and show it
myFrame.pack();
So here is what I have. I would really appreciate it if you could help me out.

I think that this issue corresponding with HierarchyListener, for comparing
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ContainerListener extends JFrame {
private static final long serialVersionUID = 1L;
public ContainerListener() {
super("Test");
setContentPane(new TestPanel());
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
pack();
setLocationRelativeTo(null);
setVisible(true);
}
public static void main(String[] parameters) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
ContainerListener containerListener = new ContainerListener();
}
});
}
private class TestPanel extends JPanel {
private static final long serialVersionUID = 1L;
TestPanel() {
setLayout(new FlowLayout(FlowLayout.LEFT));
add(new JButton(new AbstractAction("Add label") {
private static final long serialVersionUID = 1L;
private int n = 0;
#Override
public void actionPerformed(ActionEvent event) {
TestPanel.this.add(new JLabel("Label " + ++n));
validate();
}
}));
addHierarchyListener(new HierarchyListener() {
#Override
public void hierarchyChanged(HierarchyEvent e) {
System.out.println("Components Change: " + e.getChanged());
if ((e.getChangeFlags() & HierarchyEvent.DISPLAYABILITY_CHANGED) != 0) {
if (e.getComponent().isDisplayable()) {
System.out.println("Components: " + e.getChanged());
} else {
System.out.println("Components: " + e.getChanged());
}
}
}
});
addContainerListener(new ContainerAdapter() {
#Override
public void componentAdded(ContainerEvent event) {
System.out.println("componentAdded : " + event.getChild() + "containerName" + " was added");
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
}
}

I highly recommend listening to the advice given by #Jeffrey, but if you do proceed with this design, then perhaps implementing the ContainerListener interface may prove useful.
When in doubt, consult the API.

How do I make JScrollPane scroll to follow input focus?

I have a Swing app with a large panel which is wrapped in a JScrollPane. Users normally move between the panel's subcomponents by tabbing, so when they tab to something out view, I want the scroll pane to autoscroll so the component with input focus is always visible.
I've tried using KeyboardFocusManager to listen for input focus changes, and then calling scrollRectToVisible.
Here's an SSCCE displaying my current strategy (just copy/paste and run!):
import java.awt.KeyboardFocusManager;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
public class FollowFocus {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
final int ROWS = 100;
final JPanel content = new JPanel();
content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));
content.add(new JLabel(
"Thanks for helping out. Use tab to move around."));
for (int i = 0; i < ROWS; i++) {
JTextField field = new JTextField("" + i);
field.setName("field#" + i);
content.add(field);
}
KeyboardFocusManager.getCurrentKeyboardFocusManager()
.addPropertyChangeListener("focusOwner",
new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if (!(evt.getNewValue() instanceof JComponent)) {
return;
}
JComponent focused = (JComponent) evt.getNewValue();
if (content.isAncestorOf(focused)) {
System.out.println("Scrolling to " + focused.getName());
focused.scrollRectToVisible(focused.getBounds());
}
}
});
JFrame window = new JFrame("Follow focus");
window.setContentPane(new JScrollPane(content));
window.setSize(200, 200);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setVisible(true);
}
});
}
}
If you run this example, you'll notice it doesn't work very well. It does get the focus change notifications, but the call to scrollRectToVisible doesn't appear to have any effect. In my app (which is too complex to show here), scrollRectToVisible works about half the time when I tab into something outside of the viewport.
Is there an established way to solve this problem? If it makes any difference, the Swing app is built on Netbeans RCP (and most of our customers run Windows).

My comment to the other answer:
scrollRectToVisible on the component itself is the whole point of that
method ;-) It's passed up the hierarchy until a parent doing the
scroll is found
... except when the component itself handles it - as JTextField does: it's implemented to scroll horizontally to make the caret visible. The way out is to call the method on the field's parent.
Edit
just for clarity, the replaced line is
content.scrollRectToVisible(focused.getBounds());

you have to take Rectangle from JPanel and JViewPort too, then compare, for example
notice (against down-voting) for final and nice output required some work for positions in the JViewPort
import java.awt.KeyboardFocusManager;
import java.awt.Rectangle;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
//http://stackoverflow.com/questions/8245328/how-do-i-make-jscrollpane-scroll-to-follow-input-focus
public class FollowFocus {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
final int ROWS = 100;
final JPanel content = new JPanel();
content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));
content.add(new JLabel(
"Thanks for helping out. Use tab to move around."));
for (int i = 0; i < ROWS; i++) {
JTextField field = new JTextField("" + i);
field.setName("field#" + i);
content.add(field);
}
final JScrollPane scroll = new JScrollPane(content);
KeyboardFocusManager.getCurrentKeyboardFocusManager().
addPropertyChangeListener("focusOwner", new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if (!(evt.getNewValue() instanceof JComponent)) {
return;
}
JViewport viewport = (JViewport) content.getParent();
JComponent focused = (JComponent) evt.getNewValue();
if (content.isAncestorOf(focused)) {
System.out.println("Scrolling to " + focused.getName());
Rectangle rect = focused.getBounds();
Rectangle r2 = viewport.getVisibleRect();
content.scrollRectToVisible(new Rectangle(rect.x, rect.y, (int) r2.getWidth(), (int) r2.getHeight()));
}
}
});
JFrame window = new JFrame("Follow focus");
window.setContentPane(new JScrollPane(content));
window.setSize(200, 200);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setVisible(true);
}
});
}
}

Here my short summary.
Add this to your Tools class:
public static void addOnEnter(Component c, Consumer<FocusEvent> onEnter) {
FocusListener fl = new FocusListener() {
#Override
public void focusGained(FocusEvent e) {
onEnter.accept(e);
}
#Override
public void focusLost(FocusEvent e) { }
};
c.addFocusListener(fl);
}
public static void scrollToFocus(FocusEvent e) {
((JComponent) e.getComponent().getParent()).scrollRectToVisible(
e.getComponent().getBounds());
}
and use it like this:
Tools.addOnEnter(component, Tools::scrollToFocus);
component can be JTextField, JButton, ...

One major issue in your code is:
focused.scrollRectToVisible(focused.getBounds());
You are calling scrollRectToVisible on the component itself! Presumably a typo.
Make your JScrollPane a final variable and call
scrollPane.getViewport().scrollRectToVisible(focused.getBounds());

Here jtextbox is the component you want to focus and jscrollpane is your scrollpane:
jScrollpane.getVerticalScrollBar().setValue(jtextbox.getLocation().x);