I'd like to be able to react when currently highlighted item in a JComboBox drop down list changes. Note that I'm not looking for a way to get the currently selected item, but the highlighted one. When mouse hovers over this popup it highlights the item at mouse position, but this does not affect currently selected item, so I cannot simply listen via an ItemListener or ActionListener to achieve what I want.
I'm trying to create a component which consists of a JComboBox and a coupled tooltip which displays additional information (documentation) for the currently highlighted item.
As my first attempt I'm adding some code to my constructor (extended JComboBox):
import java.awt.BorderLayout;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleState;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.SwingUtilities;
import javax.swing.plaf.basic.ComboPopup;
public class SomeFrame extends JFrame {
private MyComboBox combo;
public SomeFrame() {
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setSize(100,20);
setLocationRelativeTo(null);
setLayout(new BorderLayout());
combo = new MyComboBox();
combo.setModel(new DefaultComboBoxModel(new String[]{"one", "two", "three", "four"}));
add(combo);
pack();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
SomeFrame frame = new SomeFrame();
frame.setVisible(true);
}
});
}
// this is the important part
private static class MyComboBox extends JComboBox {
public MyComboBox() {
getAccessibleContext().addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if (AccessibleContext.ACCESSIBLE_STATE_PROPERTY.equals(evt.getPropertyName())
&& AccessibleState.FOCUSED.equals(evt.getNewValue())
&& getAccessibleContext().getAccessibleChild(0) instanceof ComboPopup) {
ComboPopup popup = (ComboPopup) getAccessibleContext().getAccessibleChild(0);
JList list = popup.getList();
System.out.println("--> " + String.valueOf(list.getSelectedValue()));
}
}
});
}
}
}
It seems to work, but I got to this code through some shady channels and trial/error, so I'm thinking there has to be a better way of doing it. Any ideas? Is above code even production safe?
Good question and good solution - except that there seems to be bug in accessibleCombo which doesn't update its internal wiring on updateUI, that is, when toggling the LAF:
the accessible selection changes of the list are fired by an internal ListSelectionListener registered to the comboPopup list
the comboPopup is controlled by the ui-delegate and re/created in installUI
accessibleCombo doesn't update its internal list to the newly created and installed
Not much you can do about it. So I would listen directly to the list selection, then you have full control about re-wiring on LAF changes:
public static class XComboBox extends JComboBox {
private ListSelectionListener listener;
public XComboBox() {
uninstall();
install();
}
#Override
public void updateUI() {
uninstall();
super.updateUI();
install();
}
private void uninstall() {
if (listener == null) return;
getPopupList().removeListSelectionListener(listener);
listener = null;
}
protected void install() {
listener = new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
if (e.getValueIsAdjusting()) return;
JList list = getPopupList();
System.out.println("--> " + String.valueOf(list.getSelectedValue()));
}
};
getPopupList().addListSelectionListener(listener);
}
private JList getPopupList() {
ComboPopup popup = (ComboPopup) getUI().getAccessibleChild(this, 0);
return popup.getList();
}
}
I'm trying to create a component which consists of a JComboBox and a coupled tooltip
Create a custom renderer for the combo box. Then in the renderer use the setToolTipText(...) method.
The section Specifying Tool Tips For Cells from the JTable tutorial shows how to do this for tables. The concept should be the same for a comboBox renderer.
Related
I have a JTable with a number of rows, each row made up of a number of JPanels. I want one of the rows in the JTable to be unselectable. I have used a:
panel.setFocusable(false);
on this particular row. However, when pressing the down arrow key on the table, the selection disappears when it gets to the unfocusable panel. Is there a quick way of skipping the selection all together on this row and just selecting the next row?
You can achieve that with help of ListSelectionListener. Read more How to Write a List Selection Listener. Simple example:
import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.ListSelectionModel;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class TestFrame extends JFrame{
private int notSelectable = 2;
private JTable t1;
public TestFrame(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
init();
pack();
setVisible(true);
}
private void init() {
t1 = new JTable(10,1);
t1.getSelectionModel().addListSelectionListener(getListener());
t1.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
add(t1);
}
private ListSelectionListener getListener() {
return new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
if(t1.getSelectedRow() == notSelectable){
if(notSelectable+1 == t1.getRowCount()){
t1.getSelectionModel().setSelectionInterval(0, 0);
} else {
t1.getSelectionModel().setSelectionInterval(notSelectable+1, notSelectable+1);
}
}
}
};
}
public static void main(String... strings) {
new TestFrame();
}
}
I'm using the SwingX AutoCompleteDecorator for a JComboBox. The autocomplete feature works beautifully...
But I have trouble to identify the moment of the final user selection; to persist my data seldom.
Let me try to explain: The combobox fires an "comboBoxChanged"-ActionEvent for every selection. I have to ignore these events while the user is typing characters and the combobox is auto-matching and selecting items. If the user hits the return-key an "comboBoxEdited"-ActionEvent is generated and I can save the selected value. Great ;-)
If the mouse is used to open the JComboBox-PopUp and to select an item, the only fired event is a "comboBoxChanged"-ActionEvent (like when auto-matching or selecting an item with the cursor-keys). The mouse-clicked-Event is consumed somehow!? That's why I can't identify the final mouse selection.
How can I figure this out? My failed attempts to listen for the mouseClicked-Event are documented in this SSCCE:
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import org.jdesktop.swingx.autocomplete.AutoCompleteDecorator;
public class SearchForThePopUpMouseClick extends JPanel
{
private JComboBox<String> comboBox;
public SearchForThePopUpMouseClick()
{
comboBox = new JComboBox<String>(new String[] { "Anna", "Marc", "Maria", "Marten", "Peter" });
add(comboBox);
add(new JTextField("textfield to click"));
AutoCompleteDecorator.decorate(comboBox);
comboBox.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
System.out.println("Action Event with '" + e.getActionCommand() + " " + e.getID() + "'");
};
});
((Component) comboBox.getUI().getAccessibleChild(comboBox, 0)).addMouseListener(new MouseListener()
{
#Override
public void mouseReleased(MouseEvent e)
{
System.out.println(e);
}
#Override
public void mousePressed(MouseEvent e)
{
System.out.println(e);
}
#Override
public void mouseExited(MouseEvent e)
{
System.out.println(e);
}
#Override
public void mouseEntered(MouseEvent e)
{
System.out.println(e);
}
#Override
public void mouseClicked(MouseEvent e)
{
System.out.println(e);
}
});
}
public static void main(String[] args) throws Exception
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
SearchForThePopUpMouseClick autoCompletePanel = new SearchForThePopUpMouseClick();
JFrame frame = new JFrame("SwingX Autocomplete Example");
frame.add(autoCompletePanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
A comboBox has no notion of final selection: all selections have equal semantic weight independent on their trigger (mouse, keyboard navigation, programmatically, selection by first letter in core) and fire an actionEvent. Same behaviour for plain and decorated comboBox.
That's exactly what you need in most contexts: react to a selection always as if it were final (whatever that might mean)
If in your case you really want to regard a selection triggered by a mouseEvent as more final than those triggered by anything else (again: that's typically not recommended for a good user experience, so be very, very careful in your evaluation) you can check the modifiers returned by the actionEvent:
if ((e.getModifiers() & InputEvent.BUTTON1_MASK) != 0) {
// triggered by mouse
}
Edit
Seeing the use cases (thanks for providing them!) in the comments, realized that my beware partly barked at the wrong tree :-)
In this context, the mouse- vs. keyboard gesture have indeed different semantics
keyboard: typing in the editor as well as navigating in the popup denote the process to build the final selection, with a special key (enter) denoting a commit
mouse: clicking in the popup is both selecting and commit
JComboBox doesn't support that use-case optimally, firing too much. That's problem even swing-internally, f.i. when using a comboBox as CellEditor. That's partly fixed by a magic clientProperty:
public DefaultCellEditor(final JComboBox comboBox) {
editorComponent = comboBox;
comboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);
Detecting that property, the BasicComboBoxUI (actually the BasicComboPopup) keyStrokes navigation selects in the list of the popup only, defering the synch of the listSelection to the comboSelection until committed via enter. It's partial because the look-ahead (aka: typing and selecting by first letter) still selects (and thereby committing) immediately in the combo.
Short summary: there already is a swing-internal use-case, which leads to an already available swingx-internal solution for autoComplete editing in tables - a class named ComboBoxCellEditor. Can be used stand-alone also:
AutoCompleteDecorator.decorate( withEditor );
ComboBoxCellEditor editor = new ComboBoxCellEditor(withEditor);
CellEditorListener listener = new CellEditorListener() {
#Override
public void editingStopped(ChangeEvent e) {
// do commit stuff
}
#Override
public void editingCanceled(ChangeEvent e) {
}
};
editor.addCellEditorListener(listener);
contentPane.add(withEditor, BorderLayout.SOUTH);
how do you trap the event before the new tab is switched to?
In every Tab I have JTable and i do something with it's data(delete, add , update). I would like to do data validation(save or cancel changes) before switching to the new tab. I use Java 1.5.
class ViewPanel extends JPanel
{
private void Components() {
setPreferredSize(new Dimension(700, 400));
tabbedPane.addTab("DC", ANSFER.getIcon(),new DcTabPanel(this), "DC");
tabbedPane.addTab("PC", THUMB4.getIcon(),new PcTabPanel(this), "PC");
tabbedPane.addChangeListener(this);
add(tabbedPane);
}
public void stateChanged(ChangeEvent e) {
}
}
JTabbedPane is backed by a SingleSelectionModel. If you extend DefaultSingleSelectionModel, you can override the setSelectedIndex method and implement your logic.
// in new selection model:
public void setSelectedIndex(int index) {
// do pre-switch things here
super.setSelectedIndex(index);
}
// in ViewPanel, on tabbedPane create:
tabbedPane.setModel(newSelectionModel);
The reason you can't simply use a ChangeListener is because that fires on change. By extending the selection model, you fire before the tab change.
You can prevent tab switching by extending JTabbedPane and override setSelectedIndex(int). Here is a small example illustrating that. It simply prevents from switching between non-contiguous tabs:
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTabbedPane;
import javax.swing.SwingUtilities;
public class Test2 {
private static class BlockingTabbedPane extends JTabbedPane {
public static interface TabSwitchAllower {
public boolean allowTabSwitch(int from, int to);
}
private TabSwitchAllower allower;
public BlockingTabbedPane(TabSwitchAllower allower) {
super();
this.allower = allower;
}
#Override
public void setSelectedIndex(int index) {
if (allower == null || allower.allowTabSwitch(getSelectedIndex(), index)) {
super.setSelectedIndex(index);
}
}
}
protected static void initUI() {
final JFrame frame = new JFrame("test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BlockingTabbedPane.TabSwitchAllower allower = new BlockingTabbedPane.TabSwitchAllower() {
#Override
public boolean allowTabSwitch(int from, int to) {
if (Math.abs(from - to) == 1) {
return true;
} else {
JOptionPane.showMessageDialog(frame, "You can only switch between contiguous tabs");
}
return false;
}
};
JTabbedPane tabbedPane = new BlockingTabbedPane(allower);
for (int i = 0; i < 10; i++) {
tabbedPane.addTab("Tab-" + i, new JLabel("Hello tab " + i));
}
frame.add(tabbedPane);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
initUI();
}
});
}
}
java actionlistener on a tab
How to Write a Change Listener (Oracle Docs)
JTabbedPane API (Oracle Docs)
Those two links should help you out. I haven't really worked with tabbedPanes, but I am assuming that the getSelectedComponent() will return the current selected tab. So you can have a handle to the currentTab which will be set during instantiation. Then you can have something like this.
class TabListener implements ChangeListener {
public void stateChanged(ChangeEvent e) {
// Replace JSlider with whatever your tab's data type is
JSlider source = (JSlider)e.getSource();
// Use the 'currentTab' handle to do what you want.
currentTab = getSelectedComponent();
// I'm assuming that the 'selected component' by the time this stuff
// runs is going to be the new selected tab.
}
}
I am not too confident about my answer, but I certainly hope that this will point you towards the right direction! Please say if you need any clarification or anything! If I happen to discover anything that I think might be useful, I'll be certain to edit my answer!
I'm trying to build a javax.swing.JTextField with javax.swing.JList for auto-completing like Google.
When a write a word, Google show several matches and
when a press the ▼ I can select some match using ▲ and ▼ and
can edit my input with ◀ and ▶ .
When I press Enter key search the content in the box.
When a press Esc the box change to the original input.
My aplication is about the Bible and I want to looking for a particular word when I'm studying the Word. I have seen the Java2sAutoTextField but don't have this particular behavior with the arrow keys.
This needs a custom coded component. Definitely a class that extends JTextField and in that class you have a JPopupMenu that will contain your JList. You will have to position the JPopupMenu right under the text field so that it looks like 1 component.
Your next trick is to filter as you type. I usually do this using Java6 TableRowSorter coupled with a JTable to which I pre-fill it with data. You're gonna need some change listeners on the JTextField and intercept each key typed and fetch your data.
Key pressed
Perform query in DB (or some data storage to get similar entries)
Populate JTable with those entires
Set RowFilter with regex based on JTextField entry to filter through retrieved data
Manage your actions with key listeners
EDIT
I whipped up a sample swing app to show what I stated. This is a copy/paste example and should work right off the bat (need JDK 1.6+). I basically got what you wanted and I put comments in places where I tell you to fill in the blanks.. like for example the Escape key event is consumed and you can do whatever you want with it.
The method initTableModel() just initializes the table model with data. Normally you would want to dynamically populate the table model with data from a database or something. A lot could be tweaked, but this is for example sake ;) So this should be a good enough example for you to modify to your complete your goal. Any more than this and you have to pay me $$$ :)
package test.text.googleclone;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.regex.PatternSyntaxException;
import javax.swing.AbstractAction;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.KeyStroke;
import javax.swing.ListSelectionModel;
import javax.swing.RowFilter;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableRowSorter;
public class SearchAutoFillTest {
private JFrame frame = null;
private JTextField searchField = null;
private JPopupMenu popup = null;
private JTable searchTable = null;
private TableRowSorter<DefaultTableModel> rowSorter = null;
private DefaultTableModel searchTableModel = null;
public SearchAutoFillTest() {
searchTableModel = new DefaultTableModel();
initTableModel();
rowSorter = new TableRowSorter<DefaultTableModel>(searchTableModel);
searchTable = new JTable(searchTableModel);
searchTable.setRowSorter(rowSorter);
searchTable.setFillsViewportHeight(true);
searchTable.getColumnModel().setColumnSelectionAllowed(false);
searchTable.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
searchTable.getTableHeader().setReorderingAllowed(false);
searchTable.setPreferredSize(new Dimension(775, 100));
searchTable.setGridColor(Color.WHITE);
searchField = new JTextField();
searchField.getDocument().addDocumentListener(new DocumentListener() {
#Override
public void changedUpdate(DocumentEvent e) {
showPopup(e);
}
#Override
public void insertUpdate(DocumentEvent e) {
showPopup(e);
}
#Override
public void removeUpdate(DocumentEvent e) {
showPopup(e);
}
});
searchField.addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
int code = e.getKeyCode();
switch(code)
{
case KeyEvent.VK_UP:
{
cycleTableSelectionUp();
break;
}
case KeyEvent.VK_DOWN:
{
cycleTableSelectionDown();
break;
}
case KeyEvent.VK_LEFT:
{
//Do whatever you want here
break;
}
case KeyEvent.VK_RIGHT:
{
//Do whatever you want here
break;
}
}
}
#Override
public void keyPressed(KeyEvent e) {
}
});
KeyStroke keyStroke = KeyStroke.getKeyStroke("ESCAPE");
searchField.getInputMap().put(keyStroke, "ESCAPE");
searchField.getActionMap().put("ESCAPE", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
//Do what you wish here with the escape key.
}
});
popup = new JPopupMenu();
popup.add(searchTable);
popup.setVisible(false);
popup.setBorder(BorderFactory.createEmptyBorder());
JPanel searchPanel = new JPanel(new BorderLayout(5, 5));
searchPanel.setBorder(BorderFactory.createEmptyBorder(4, 4, 4, 4));
searchPanel.add(searchField, BorderLayout.CENTER);
frame = new JFrame();
frame.setLayout(new BorderLayout(5, 5));
frame.add(searchPanel, BorderLayout.NORTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 500);
center(frame);
frame.setVisible(true);
}
private final void newFilter() {
RowFilter<DefaultTableModel, Object> rf = null;
try {
rf = RowFilter.regexFilter(getFilterText(), 0);
}
catch(PatternSyntaxException e) {
return;
}
rowSorter.setRowFilter(rf);
}
private final String getFilterText() {
String orig = searchField.getText();
return "("+orig.toLowerCase()+")|("+orig.toUpperCase()+")";
}
private void showPopup(DocumentEvent e) {
if(e.getDocument().getLength() > 0) {
if(!popup.isVisible()) {
Rectangle r = searchField.getBounds();
popup.show(searchField, (r.x-4), (r.y+16));
popup.setVisible(true);
}
newFilter();
searchField.grabFocus();
}
else {
popup.setVisible(false);
}
}
private void cycleTableSelectionUp() {
ListSelectionModel selModel = searchTable.getSelectionModel();
int index0 = selModel.getMinSelectionIndex();
if(index0 > 0) {
selModel.setSelectionInterval(index0-1, index0-1);
}
}
private void cycleTableSelectionDown() {
ListSelectionModel selModel = searchTable.getSelectionModel();
int index0 = selModel.getMinSelectionIndex();
if(index0 == -1) {
selModel.setSelectionInterval(0, 0);
}
else if(index0 > -1) {
selModel.setSelectionInterval(index0+1, index0+1);
}
}
private void initTableModel() {
String[] columns = new String[] {"A"};
String[][] data = new String[][]
{
new String[] {"a"},
new String[] {"aa"},
new String[] {"aaab"},
new String[] {"aaabb"},
new String[] {"aaabbbz"},
new String[] {"b"},
new String[] {"bb"},
new String[] {"bbb"},
new String[] {"bbbbbbb"},
new String[] {"bbbbbbbeee"},
new String[] {"bbbbbbbeeexxx"},
new String[] {"ccc"},
new String[] {"cccc"},
new String[] {"ccccc"},
new String[] {"cccccaaaa"},
new String[] {"ccccccaaaa"},
};
searchTableModel.setDataVector(data, columns);
}
private void center(Window w) {
int screenWidth = Toolkit.getDefaultToolkit().getScreenSize().width;
int screenHeight = Toolkit.getDefaultToolkit().getScreenSize().height;
int windowWidth = w.getWidth();
int windowHeight = w.getHeight();
if (windowHeight > screenHeight) {
return;
}
if (windowWidth > screenWidth) {
return;
}
int x = (screenWidth - windowWidth) / 2;
int y = (screenHeight - windowHeight) / 2;
w.setLocation(x, y);
}
public static void main(String ... args) {
new SearchAutoFillTest();
}
}
This component is called autocomplete and is included in a so called swing extensions porject.
Just have a look at: http://swingx.java.net/
There is a webstart with demos: http://swinglabs-demos.java.net/demos/swingxset6/swingxset.jnlp
use AutoComplete JTextField placed into JToolBar / MenuBar, notice you must to sort ArrayList before usage,
use undecoratted JDialog instead of JPopup (still have got a few important bugs),
a) create only one JDialog with parent to the JTextField or JMenuBar or JFrame,
b) always to search for getBounds from AutoComplete JTextField before visible JDialog on the screen, this Bounds are for possitioning JDialog correctly on the screen
c) wrap JDialog#setVisible(true) to the invokeLater()
override Escape for JDialog.setVisible(false)
put there close / hide JButton to avoiding overrive rest of important methods on focusLost (this calendar have got excelent workaround on focusLost, mouseClick, etc ...., could it be very easy to replace calendar funcionality with result from Comparator, you have to download codesource)
you can put there (my view) 6 / 9 / max 12 buttons, you can remove JButton Feels by setBackground(Color.white) for example, you cann't, please don't do it something with JDialog and these JButtons, you job will be only to setText("result from Comparator")
in the case that your ArrayList for AutoComplete JTextField was sorted, then you have two choises
a) easiest override bias from AutoComplete funcionality by add fils separate array for setText() for 6 / 9 / max 12 buttons on popup JDialog, if you setBackground(Color.white), then you don't care somehow about to hide JButtons without text
b) another way could be to create own Comparator for searching (the same AutoComplete funcionality) first 6 / 9 / max 12 matches,
for capturing an events from 6 / 9 / max 12 JButtons use putClientProperty or EventHandler or Swing Actions, where you only to test if text isEmpty :-),
maybe Swing Actions could be the best of ways because its events are scallable and you can enabled/disable (if JButtons text isEmpty) output from this Action by default
It sounds like you want a JComboBox (see Swing guide) rather than a JTextField/JList.
Of course, then you have a drop-down button, but there are possible ways to deal with this - see here.
It would be something along these lines:
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import javax.swing.*;
public class Component extends JComponent {
private final static String[] terms = {"Jesus",
"Jesus walks on water" //...
};
private static ArrayList<String> recent = new ArrayList<String>();
JTextField jtf;
JList jl;
public Component(){
// set up design
jtf = new JTextField();
jtf.setSize(this.getWidth() - 25, 25);
this.add(jtf);
//...
// add key listeners
}
class Listener implements KeyListener{
#Override
public void keyPressed(KeyEvent arg0) {
}
#Override
public void keyReleased(KeyEvent arg0) {
}
#Override
public void keyTyped(KeyEvent arg0) {
if (arg0.getKeyCode() == KeyEvent.VK_DOWN){
// set next item on list
}
else if (arg0.getKeyCode() == KeyEvent.VK_UP){
// set previous item on list
}
else if (arg0.getKeyCode() == KeyEvent.VK_ENTER){
// search
}
else if (arg0.getKeyCode() == KeyEvent.VK_ESCAPE){
jtf.setText("");
}
else{
// check list for matches
}
}
}
}
The default behavior is that all key events go to the component which has the focus. So what you need to do is identify keys which should really go to the other component and install a KeyListener to both.
In that listener, you can forward the events to the other component.
See this answer how to dispatch an event to a new component. In your case, source must be the other component (the list, if your text field originally received the event and vice versa).
i'm having problems with this listener, the gui in general constructs and works fine, also the jlist is there but when i select some items in the list i dont see the results and also not the printl() i wrote for test purpose, pls note this code is contained within the getJContentPane in order to add the event handler at init-time
private JList myList=new JList(dlm);//a defaultlistmodel
myList.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent evt) {
if (evt.getValueIsAdjusting()){
System.out.println("Eventhandler called");
return;
}
System.out.println("Eventhandler called");
doMyMethod(evt);
}
});
The doMyMethod():
private void doMyMethod(ListSelectionEvent e){
if(e.getValueIsAdjusting()){
return;
}else{
String item=(String)e.getSource();
accounter.add(item);
}
}
It is a very simple method which takes as parameter an instance of ListSelectionEvent
The main problem in my opinion is not the doMyMethod() which performs very basic actions but the fact that the eventHandler is not fired at all, it seems lik the gui does not "listen" to this list at all
Any idea?
here the initialisation code:
private JScrollPane getScrollBox() {
if (scrollboxBox == null) {
scrollboxBox = new JScrollPane();
scrollBox.setBounds(new Rectangle(280, 56, 245, 204));
scrollBox.getViewport().add(myList,null);
myList.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent evt) {
System.out.println("addListSelectionListener");
if (evt.getValueIsAdjusting()){
System.out.println("Eventhandler called");
return;
}
System.out.println("Eventhandler called");
doMyMethod(evt);
}
});
}
return scrollboxBox;
}
After trying to understand what is going on in your question I understood that you are failing to get selected item in the list, when the selection is changed.
To present you how this could be achieved I have built the below example. You can observe there when each part of the if else is called. The if(e.getValueIsAdjusting()) is execute always when you drag the moue over items. The else part is called when you release the mouse while previously clicked on an item.
There are some serious issues in the code that you have provided, therefore I tried to remove all that is unnecessary, e.g.
1.The doMyMethod() method and the if(e.getValueIsAdjusting()) piece of code that is in it would never be called since you already are checking that condition before it is called. Plus there is no need to code a method working on listener's events, this code should stay inside the listener which is private. Then if you want to call programmatically its code you would call the listener.valueChanged(evt).
2.The evt.getSource() returns the object which is author of the event in this case the myList not the selected item which I think you were after, for this use the getSelectedValue() on the source or myList directly since this listener serves only this list.
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class ListTest extends JPanel
{
private JScrollPane myScrollPane;
private JList myList;
private ListSelectionListener lSL = new ListSelectionListener()
{
#Override
public void valueChanged(ListSelectionEvent evt)
{
if(evt.getValueIsAdjusting())
{
System.out.println("Eventhandler called evt.getValueIsAdjusting() true");
return;
}
else
{
// String item = (String) evt.getSource();//!!!Exception casting JList to String
//maybe what you need is getSelectedValue()
System.out.println("else called myList.getSelectedValue() ="+myList.getSelectedValue());
}
}
};
private ListTest()
{
int noRows = 25;
Object[] listData = new String[noRows];
for(int i =0; i < noRows; i++)
listData[i]= "Oi "+i;
this.myList = new JList(listData);
this.myScrollPane = new JScrollPane(myList);
myList.addListSelectionListener(lSL);
add(myScrollPane);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
ListTest p = new ListTest();
JPanel contentPane = new JPanel();
contentPane.add(p);
JFrame f = new JFrame();
f.setContentPane(contentPane);
f.setSize(800, 600);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
});
}
}
Hope that even if it doesn't solve your problem it at least will be helpful in building an SSCCE for us.