I need to refresh drop down list item just before doping down. I choose focusGained event. But when I do deactivate/activate form I have two events fired in actionPerformed that prints out :
***null
***aaa
I was not duing any dropdown selection why they are there?
Is focusGained right place to refresh items in JComboBox? What is better place of doing that?
package components;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ComboBoxDemo extends JPanel
implements ActionListener , FocusListener {
JLabel picture;
public ComboBoxDemo() {
super(new BorderLayout());
JComboBox petList = new JComboBox();
petList.addItem("1");
petList.addItem("2");
petList.addItem("3");
petList.addActionListener(this);
petList.addFocusListener(this);
add(petList, BorderLayout.PAGE_START);
setBorder(BorderFactory.createEmptyBorder(200,200,200,200));
}
/** Listens to the combo box. */
public void actionPerformed(ActionEvent e) {
JComboBox cb = (JComboBox)e.getSource();
String petName = (String)cb.getSelectedItem();
System.out.println("***"+ petName);
}
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("ComboBoxDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new ComboBoxDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
public void focusGained(FocusEvent fe) {
JComboBox cb = (JComboBox)fe.getSource();
cb.removeAllItems();
cb.addItem("aaa");
}
public void focusLost(FocusEvent fe) {
}
}
Related
This is my first question and I'm realy sorry for my English. I don't want to navigation in JComboBox's dropdown list show the selected item in the "JComboBox's main field" (sorry, don't know how to call it, see the images).
This is what happen when I navigate in list:
But I want something like this:
and when I press Enter or clicked on item, it appear in the main field.
Here is my code:
import javax.swing.*;
import javax.swing.text.JTextComponent;
import java.awt.*;
public class ComboTest {
JFrame frame;
JPanel panel;
String[] choices = new String[]{
"Java",
"Python",
"C++",
"PHP",
"Perl"
};
JComboBox<String> comboBox = new JComboBox<>(choices);
JTextComponent textComponent;
public static void main(String[] args){
new ComboTest();
}
public ComboTest() {
frame = new JFrame();
panel = new JPanel();
textComponent = (JTextComponent) comboBox.getEditor().getEditorComponent();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 150);
frame.setResizable(false);
panel.setLayout(new FlowLayout());
comboBox.setEditable(true);
comboBox.setSelectedItem(null);
panel.add(comboBox);
frame.add(panel);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
Try this code block
comboBox.addPopupMenuListener(new PopupMenuListener() {
#Override
public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
//when Popupmenu is visible, remove the combobox editor text
comboBox.getEditor().setItem(null);
}
#Override
public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
}
#Override
public void popupMenuCanceled(PopupMenuEvent e) {
}
});
Thanks to zilk. Your answer helped me to solve this. The listener addPopupMenuListener doesn't work for me. But when I changed the addPopupMenuListener to addItemListener, everything worked fine.
comboBox.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(final ItemEvent itemEvent) {
comboBox.getEditor().setItem(null);
comboBox.getEditor().getEditorComponent().addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent e) {
super.keyPressed(e);
if(e.getKeyCode() == KeyEvent.VK_ENTER)
{
comboBox.getEditor().setItem(itemEvent.getItem());
}
}
});
}
});
I have 2 classes. Both implements runnable to create the GUI. The first one is the main, and the second one is the secondary class.
I want within the actionlistener of the main class to startup the secondary class.
Here is the code (the two classes are separated files):
public class Main implements Runnable
{
private JTextField txt1, txt2;
private JLabel lbl1, lbl2;
public void run()
{
JFrame frame = new JFrame("Secondary");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container pane = frame.getContentPane();
JPanel background = new JPanel();
background.setLayout(new BoxLayout(background, BoxLayout.LINE_AXIS));
.........
// Horizontally adding the textbox and button in a Box
Box box = new Box(BoxLayout.Y_AXIS);
......
background.add(box);
pane.add(background);
frame.pack();
frame.setVisible(true);
}
private class SListener implements ActionListener
{
public void actionPerformed(ActionEvent a)
{
Secondary s = new Secondary();
}
}
public static void main (String[] args)
{
Main gui = new Main();
SwingUtilities.invokeLater(gui);
}
}
public class Secondary implements Runnable
{
private JTextField txt1, txt2;
private JLabel lbl1, lbl2;
public Secondary()
{
Secondary gui = new Secondary();
SwingUtilities.invokeLater(gui);
}
public void run()
{
JFrame frame = new JFrame("Secondary");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container pane = frame.getContentPane();
JPanel background = new JPanel();
background.setLayout(new BoxLayout(background, BoxLayout.LINE_AXIS));
.........
// Horizontally adding the textbox and button in a Box
Box box = new Box(BoxLayout.Y_AXIS);
......
background.add(box);
pane.add(background);
frame.pack();
frame.setVisible(true);
}
}
I want to keep the code in two files, I don't want to mixed the two classes in one file.
As you can see from the code, in the Secondary class, in it's constructor I create an Instance of the Secondary class and I run the gui so that when the Instance of this class is created in the Main class, to run the gui.
Unfortunately this technique is not working.
Any ideas?
Thanks
The following line are complety wrong:
public Secondary(){
Secondary gui = new Secondary();
SwingUtilities.invokeLater(gui);
}
Each time you call new Secondary() somewhere in your code, the above code will be triggered, which in turn calls new Secondary() again, and again, and again, ... and your program is blocked.
You probably want to replace it either by
public Secondary(){
SwingUtilities.invokeLater(this);
}
which will avoid the loop, but this is weird behaviour for a constructor.
It makes much more sense to switch to an empty constructor (or delete it all together)
public Secondary(){
}
and rewrite your listener to
public void actionPerformed(ActionEvent a){
Secondary s = new Secondary();
SwingUtilities.invokeLater( s );
}
I would recommend that you completely re-design your program. I find that it is most helpful to gear my GUI's towards creation of JPanels, not top level windows such as JFrame, which can then be placed into JFrames or JDialogs, or JTabbedPanes, or swapped via CardLayouts, wherever needed. I find that this greatly increase the flexibility of my GUI coding, and is exactly what I suggest that you do. So...
Your first class creates a JPanel that is then placed into a JFrame.
In the first class's ActionListener, create an instance of the 2nd class, place it into a JDialog (not a JFrame), and then display it.
For example,
import java.awt.Component;
import java.awt.Dialog.ModalityType;
import java.awt.Dimension;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.*;
public class TwoWindowEg {
public TwoWindowEg() {
// TODO Auto-generated constructor stub
}
private static void createAndShowGui() {
GuiPanel1 mainPanel = new GuiPanel1();
JFrame frame = new JFrame("Main GUI");
frame.setDefaultCloseOperation(JFrame.DISPOSE_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();
}
});
}
}
class GuiPanel1 extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private GuiPanel2 guiPanel2 = new GuiPanel2(); // our second class!
private JDialog dialog = null; // our JDialog
public GuiPanel1() {
setBorder(BorderFactory.createTitledBorder("GUI Panel 1"));
add(new JButton(new LaunchNewWindowAction("Launch New Window")));
add(new JButton(new DisposeAction("Exit", KeyEvent.VK_X)));
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class LaunchNewWindowAction extends AbstractAction {
public LaunchNewWindowAction(String name) {
super(name);
}
#Override
public void actionPerformed(ActionEvent e) {
if (dialog == null) {
// get the Window that holds this JPanel
Window win = SwingUtilities.getWindowAncestor(GuiPanel1.this);
dialog = new JDialog(win, "Second Window", ModalityType.APPLICATION_MODAL);
dialog.add(guiPanel2);
dialog.pack();
}
dialog.setVisible(true);
}
}
}
class GuiPanel2 extends JPanel {
public GuiPanel2() {
setBorder(BorderFactory.createTitledBorder("GUI Panel 1"));
add(new JLabel("The second JPanel/Class"));
add(new JButton(new DisposeAction("Exit", KeyEvent.VK_X)));
}
}
class DisposeAction extends AbstractAction {
public DisposeAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
Component comp = (Component) e.getSource();
Window win = SwingUtilities.getWindowAncestor(comp);
win.dispose();
}
}
Alternatively, you could swap JPanel "views" using a CardLayout, but either way, you will want to avoid showing two JFrames. Please have a look at The Use of Multiple JFrames, Good/Bad Practice?.
I've searched and searched and found like 800 solutions, but none of 'em seems to work with my problem. I'm removing an item from a JList using a JButton, and then i want to refresh the GUI in the actionPerformed method. But things like repaint() or updateUI() hasn't helped. Here is my code:
public class Watchlist3 extends JPanel {
public static ArrayList<String> stocks = new ArrayList<String>();
JButton addStock, removeStock, viewStock, updaterInterval;
JLabel stocksAdded, currentInterval, listTitle;
JList stocklist;
JScrollPane listScroller;
public Watchlist3(JFrame frame) {
super(new BorderLayout());
//Adding some sample-components to the list
stocks.add("PLUG");
stocks.add("IDN");
stocks.add("GOOG");
//Create the components
addStock = new JButton("Add Stock");
addStock.setOpaque(true);
addStock.setBackground(Color.RED);
add(addStock, BorderLayout.LINE_START);
removeStock = new JButton("Remove Stock");
removeStock.setOpaque(true);
removeStock.setBackground(Color.YELLOW);
removeStock.putClientProperty("SENT_FRAME", frame);
add(removeStock, BorderLayout.LINE_END);
stocklist = new JList(stocks.toArray());
stocklist.setOpaque(true);
stocklist.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
stocklist.setLayoutOrientation(JList.HORIZONTAL_WRAP);
add(listScroller = new JScrollPane(stocklist), BorderLayout.CENTER);
removeStock.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
int index = stocklist.getSelectedIndex();
if(index != -1){
stocks.remove(index);
System.out.println(stocks);
/* Here is where id like to refresh the gui! */
}
} catch (Exception ex) {}
}
});
}
private static void createAndShowGUI() {
//Create and set up the window.
final JFrame frame = new JFrame("Watchlist");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
Watchlist3 newContentPane = new Watchlist3(frame);
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
Thanks in advance
You are removing from stocks List collection but not updating the JList model.
To update list model you need put this
// Add this item to the list and refresh
// convert stock list to Object array becuase seListData accept Object[]
Object[] array = stocks.toArray(new Object[stocks.size()]);
stocklist.setListData(array);
listScroller.revalidate();
listScroller.repaint();
Could you please help me on this one? I have a JDialog with some textfields, checkboxes and buttons. I want that when the frame is not focused anymore, to disappear. So I added a focus listener to the JDialog and when the focus is lost, I call dialog.setVisible(false);. The problem is that if I click on the checkbox,textfield or button, the frame loses it's focus and disappears. How could I keep it focused until the user clicks outside it's area?
EDIT : The "frame" I am referring to is a JDialog. I don't use a Frame nor a JFrame. All the components are placed on the JDialog. I want it to hide when not focused, but keep it focused until the user clicks outside it's area.
Seems like you had added the wrong Listener, what you should be adding is addWindowFocusListener(...), see this small sample program, is this what you want to happen :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class DialogFocus
{
private JFrame frame;
private MyDialog myDialog;
public DialogFocus()
{
}
private void createAndDisplayGUI()
{
frame = new JFrame("JFRAME");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
myDialog = new MyDialog(frame, "My Dialog", false);
JButton showButton = new JButton("SHOW DIALOG");
showButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
if (!(myDialog.isShowing()))
myDialog.setVisible(true);
}
});
frame.add(showButton, BorderLayout.PAGE_END);
frame.setSize(300, 300);
frame.setVisible(true);
}
public static void main(String\u005B\u005D args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new DialogFocus().createAndDisplayGUI();
}
});
}
}
class MyDialog extends JDialog
{
private WindowFocusListener windowFocusListener;
public MyDialog(JFrame frame, String title, boolean isModal)
{
setTitle(title);
setModal(isModal);
JPanel contentPane = new JPanel();
JTextField tfield = new JTextField(10);
JComboBox cbox = new JComboBox();
cbox.addItem("One");
cbox.addItem("Two");
cbox.addItem("Three");
contentPane.add(tfield);
contentPane.add(cbox);
windowFocusListener = new WindowFocusListener()
{
public void windowGainedFocus(WindowEvent we)
{
}
public void windowLostFocus(WindowEvent we)
{
setVisible(false);
}
};
addWindowFocusListener(windowFocusListener);
add(contentPane);
pack();
}
}
Make the dialog modal, then the user cannot click on the frame.
Check the FocusEvent
it has public Component getOppositeComponent(). If the opposite component is child component of the JDialog don't hide the dialog.
I create a Popup using the PopupFactory.getPopup method. According to the documentation, I am required to call the hide() method on the popup when it is no longer needed.
In my application, the popup is the child of a JLabel which may be removed from the current frame in a number of different situations. (Either the JLabel itself or one of its parent containers is removed.) Rather that calling hide() in every single place (and making the Popup object available in all these places) I would prefer to be able to detect the removal of the JLabel or one of its parent containers.
How can I detect the removal? I naively assumed that the removal of a component meant the removal/hiding of its children, but as the code below shows, the popup survives the removal of the JLabel.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Xyzzy extends JFrame {
static Xyzzy frame;
static JPanel panel;
static JLabel text1;
static JLabel text2;
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
frame = new Xyzzy();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.PAGE_AXIS));
panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.LINE_AXIS));
frame.add(panel);
text1 = new JLabel("text1");
text2 = new JLabel("text2");
panel.add(text1);
frame.add(new JButton(new AbstractAction("Add popup") {
public void actionPerformed(ActionEvent e) {
PopupFactory factory = PopupFactory.getSharedInstance();
Popup popup = factory.getPopup(text1, new JLabel("POPUP"),frame.getX()+300,frame.getY()+300);
popup.show();
}
}));
frame.add(new JButton(new AbstractAction("New label") {
public void actionPerformed(ActionEvent e) {
panel.remove(text1);
panel.add(text2);
panel.revalidate();
}
}));
frame.setSize(600, 600);
frame.setVisible(true);
}
});
}
}
This code creates a JFrame displaying the text "text1" and two buttons. If you press the button labeled "Add popup", a Popup with the text "POPUP" appears in the window. This Popup is a child of text1. Press the "New label" button and "text1" is removed from the display, but the Popup survives.
I need to be able to detect when text1 or the containing panel is removed so that I can hide the popup. I want to avoid adding code where the actual remove() method is called.
You can use HierarchyListener:
public void actionPerformed(ActionEvent e) {
PopupFactory factory = PopupFactory.getSharedInstance();
final Popup popup = factory.getPopup(text1, new JLabel("POPUP"),frame.getX()+300,frame.getY()+300);
text1.addHierarchyListener(new HierarchyListener() {
public void hierarchyChanged(HierarchyEvent e) {
if (e.getID() == HierarchyEvent.HIERARCHY_CHANGED
&& (e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0) {
popup.hide();
}
}
});
popup.show();
}