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Editable JComboBox firing ActionListener when losing focus

I am writing a class (UIPromptComboBox) that extends JComboBox. The combobox is editable and for one application of the class it is implemented with a controlling ActionListener.
Currently, when the combobox is edited it fires the ActionListener which is good. However this ActionListener is also fired when I deselect the combobox and I cannot distinguish between the two events nor do I want it to fire when the combobox is deselected.
Implementing Class
private void addUIField() {
// Initialise and place combobox
this.myGuiTextField = new UIPromptComboBox();
myGuiTextField.setSize(COMBO_WIDTH, defaultHeight);
GuiUtils.positionControl(myPanel, myGuiTextField, myTop, PROMPT_X_LOC);
//Add action listener
myGuiTextField.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
if (evt.getActionCommand().equals("comboBoxEdited")) {
newUIcreated((UIPromptComboBox) evt.getSource());
}
}
private void newUIcreated(UIPromptComboBox alteredGuiTextField) {
try {
UIPrompt uip = alteredGuiTextField.getUIPrompt(((PowerPointTextItem) myPPTRef).getValue());
if (!simInfo.isInPrompts(uip)) {
simInfo.addUIPrompt(uip);
alteredGuiTextField.addNewUIPrompt(uip);
}
} catch (MissingPowerpointItem ex) {
Exceptions.printStackTrace(ex);
}
}
});
}
Class that extends JComboBox
public class UIPromptComboBox extends JComboBox {
public UIPromptComboBox(UIPrompt[] items) {
super(items);
this.setEditable(true);
}
public UIPromptComboBox() {
this.setEditable(true);
this.setEnabled(false);
}
/**
* returns either the selected UI prompt or a new prompt using the example
* text
*
* #param exampleText only used if new prompt is created
* #return UI prompt selected
*/
public UIPrompt getUIPrompt(String exampleText) {
UIPrompt uIPrompt = null;
Object returnedItem = this.getSelectedItem();
if (returnedItem instanceof UIPrompt) {
uIPrompt = (UIPrompt) returnedItem;
} else if (returnedItem instanceof String) {
uIPrompt = new UIPrompt((String) returnedItem, exampleText);
}
return uIPrompt;
}
public void addNewUIPrompt(UIPrompt newPrompt) {
ActionListener[] actionListerners = this.getActionListeners();
this.removeActionListener(this);
this.addItem(newPrompt);
this.setSelectedItem(newPrompt);
for (ActionListener al : actionListerners) {
this.addActionListener(al);
}
}
/**
* Used for displaying a report value sentence
* i.e. a string that is not associated with UI Prompts
* #param newText report value sentence
*/
public void setText(String newText) {
this.removeAllItems();
this.addItem(newText);
this.setSelectedItem(newText);
}
/**
* For when the UI prompts can be added on construction
*
* #param currentUIs list of UI promts
*/
public void addItems(UIPrompt[] currentUIs) {
this.removeAllItems();
DefaultComboBoxModel boxModel = new DefaultComboBoxModel(currentUIs);
this.setModel(boxModel);
}
}
The multiple firing due to losing focus is causing multiple objects to be created and added to the list. I think I may have implemented the ActionListener incorrectly. Thank you for your help

as you stated you only want the event to fire if the user presses enter. a better way to implement that, would be using an keylistener instead of an action listener.
myGuiTextField.addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER) {
newUIcreated((UIPromptComboBox) evt.getSource());
}
}
private void newUIcreated(UIPromptComboBox alteredGuiTextField) {
try {
UIPrompt uip = alteredGuiTextField.getUIPrompt(((PowerPointTextItem) myPPTRef).getValue());
if (!simInfo.isInPrompts(uip)) {
simInfo.addUIPrompt(uip);
alteredGuiTextField.addNewUIPrompt(uip);
}
} catch (MissingPowerpointItem ex) {
Exceptions.printStackTrace(ex);
}
}
});
this should now only fire your event newUIcreated, once the users presses enter and at no other time. replace your action listener with this

I have now finally found the issue.
The displaying of the UIPrompt included the addition of a string that sometimes contained a new line character.
The action of clicking another field was triggering the render of the UIPrompt however when this contained a newline character it was triggering the ActionListener again. This what the reason for the repeated action of comboBoxEdited.

Pressing JButton inside JTable via keyboard

I want to show a JButton within a JTable. This is nothing special, and I found a lot of examples doing this. However, I always have issues with pressing the buttons via Keyboard (not via mouse). I expect that I can select a cell and push (also visually) the button by pressing SPACE (no mnemonics).
Two snippets work like a charm, except supporting keys:
http://tips4java.wordpress.com/2009/07/12/table-button-column/
The author claims that keys work. I believe that they did, but not on all my systems I checked. However, supported mnemonics work perfectly.
(posted here: Adding Jbutton to JTable)
http://www.java2s.com/Code/Java/Swing-Components/ButtonTableExample.htm
(posted here: Adding Jbutton to JTable)
In the example, it works perfectly! However, it doesn't work for my table. Just disable row selection (I have to use cell selection), and pressing the button via key doesn't work anymore:
table.setRowSelectionAllowed(false);
I tried hard figuring out what's going wrong or how to fix it, but I failed. My only achievement is to call the action behind the button, but the button is not pressed (I mean the visual behavior).
Some information added:
I used... (in many combinations)
Ubuntu 10.04, Windows 7, Windows 8
Java 7u21, JDK 1.6.0_33, OpenJDK Runtime Environment (IcedTea6 1.8.1) (6b18-1.8.1-0ubuntu1)
WindowsLookAndFeel, Metal (Cross Platform LAF), Nimbus
0% success!
TableTest.java
import java.awt.event.ActionEvent;
import java.util.LinkedList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.AbstractTableModel;
public class TableTest extends JFrame {
public TableTest() {
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTable table = new JTable(new TestModel());
table.setRowSelectionAllowed(false);
table.getColumnModel().getColumn(1).setPreferredWidth(3);
table.getColumnModel().getColumn(2).setPreferredWidth(3);
this.add(new JScrollPane(table));
Action increase = new AbstractAction("+") {
#Override
public void actionPerformed(ActionEvent e) {
JTable table = (JTable) e.getSource();
int row = Integer.valueOf(e.getActionCommand());
TestModel model = (TestModel) table.getModel();
model.increment(row, 0);
}
};
ButtonColumn inc = new ButtonColumn(table, increase, 1);
Action decrease = new AbstractAction("-") {
#Override
public void actionPerformed(ActionEvent e) {
JTable table = (JTable) e.getSource();
int row = Integer.valueOf(e.getActionCommand());
TestModel model = (TestModel) table.getModel();
model.decrement(row, 0);
}
};
ButtonColumn dec = new ButtonColumn(table, decrease, 2);
pack();
}
public static void main(String[] args) {
new TableTest().setVisible(true);
}
}
class TestModel extends AbstractTableModel {
List<TestRecord> records = new LinkedList<TestRecord>();
private static class TestRecord {
private int val = 0;
}
public void increment(int row, int col) {
records.get(row).val++;
fireTableCellUpdated(row, 0);
}
public void decrement(int row, int col) {
records.get(row).val--;
fireTableCellUpdated(row, 0);
}
public TestModel() {
records.add(new TestRecord());
records.add(new TestRecord());
}
#Override
public Class<?> getColumnClass(int col) {
if (col == 0) {
return Integer.class;
} else {
return ButtonColumn.class;
}
}
#Override
public boolean isCellEditable(int row, int col) {
return true;
}
#Override
public int getColumnCount() {
return 3;
}
#Override
public int getRowCount() {
return records.size();
}
#Override
public Object getValueAt(int row, int col) {
if (col == 0) {
return records.get(row).val;
} else if (col == 1) {
return "+";
} else {
return "-";
}
}
}
ButtonColumn.java
import java.awt.Color;
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.AbstractCellEditor;
import javax.swing.Action;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.border.Border;
import javax.swing.border.LineBorder;
import javax.swing.table.TableCellEditor;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumnModel;
/**
* The ButtonColumn class provides a renderer and an editor that looks like a
* JButton. The renderer and editor will then be used for a specified column in
* the table. The TableModel will contain the String to be displayed on the
* button.
*
* The button can be invoked by a mouse click or by pressing the space bar when
* the cell has focus. Optionally a mnemonic can be set to invoke the button.
* When the button is invoked the provided Action is invoked. The source of the
* Action will be the table. The action command will contain the model row
* number of the button that was clicked.
*
*/
public class ButtonColumn extends AbstractCellEditor implements
TableCellRenderer, TableCellEditor, ActionListener, MouseListener {
private JTable table;
private Action action;
private int mnemonic;
private Border originalBorder;
private Border focusBorder;
private JButton renderButton;
private JButton editButton;
private Object editorValue;
private boolean isButtonColumnEditor;
/**
* Create the ButtonColumn to be used as a renderer and editor. The renderer
* and editor will automatically be installed on the TableColumn of the
* specified column.
*
* #param table
* the table containing the button renderer/editor
* #param action
* the Action to be invoked when the button is invoked
* #param column
* the column to which the button renderer/editor is added
*/
public ButtonColumn(JTable table, Action action, int column) {
this.table = table;
this.action = action;
renderButton = new JButton();
editButton = new JButton();
editButton.setFocusPainted(false);
editButton.addActionListener(this);
originalBorder = editButton.getBorder();
setFocusBorder(new LineBorder(Color.BLUE));
TableColumnModel columnModel = table.getColumnModel();
columnModel.getColumn(column).setCellRenderer(this);
columnModel.getColumn(column).setCellEditor(this);
table.addMouseListener(this);
}
/**
* Get foreground color of the button when the cell has focus
*
* #return the foreground color
*/
public Border getFocusBorder() {
return focusBorder;
}
/**
* The foreground color of the button when the cell has focus
*
* #param focusBorder
* the foreground color
*/
public void setFocusBorder(Border focusBorder) {
this.focusBorder = focusBorder;
editButton.setBorder(focusBorder);
}
public int getMnemonic() {
return mnemonic;
}
/**
* The mnemonic to activate the button when the cell has focus
*
* #param mnemonic
* the mnemonic
*/
public void setMnemonic(int mnemonic) {
this.mnemonic = mnemonic;
renderButton.setMnemonic(mnemonic);
editButton.setMnemonic(mnemonic);
}
#Override
public Component getTableCellEditorComponent(JTable table, Object value,
boolean isSelected, int row, int column) {
if (value == null) {
editButton.setText("");
editButton.setIcon(null);
} else if (value instanceof Icon) {
editButton.setText("");
editButton.setIcon((Icon) value);
} else {
editButton.setText(value.toString());
editButton.setIcon(null);
}
this.editorValue = value;
return editButton;
}
#Override
public Object getCellEditorValue() {
return editorValue;
}
//
// Implement TableCellRenderer interface
//
#Override
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
if (isSelected) {
renderButton.setForeground(table.getSelectionForeground());
renderButton.setBackground(table.getSelectionBackground());
} else {
renderButton.setForeground(table.getForeground());
renderButton.setBackground(UIManager.getColor("Button.background"));
}
if (hasFocus) {
renderButton.setBorder(focusBorder);
} else {
renderButton.setBorder(originalBorder);
}
// renderButton.setText( (value == null) ? "" : value.toString() );
if (value == null) {
renderButton.setText("");
renderButton.setIcon(null);
} else if (value instanceof Icon) {
renderButton.setText("");
renderButton.setIcon((Icon) value);
} else {
renderButton.setText(value.toString());
renderButton.setIcon(null);
}
return renderButton;
}
//
// Implement ActionListener interface
//
/*
* The button has been pressed. Stop editing and invoke the custom Action
*/
#Override
public void actionPerformed(ActionEvent e) {
int row = table.convertRowIndexToModel(table.getEditingRow());
fireEditingStopped();
// Invoke the Action
ActionEvent event = new ActionEvent(table,
ActionEvent.ACTION_PERFORMED, "" + row);
action.actionPerformed(event);
}
//
// Implement MouseListener interface
//
/*
* When the mouse is pressed the editor is invoked. If you then then drag
* the mouse to another cell before releasing it, the editor is still
* active. Make sure editing is stopped when the mouse is released.
*/
#Override
public void mousePressed(MouseEvent e) {
if (table.isEditing() && table.getCellEditor() == this)
isButtonColumnEditor = true;
}
#Override
public void mouseReleased(MouseEvent e) {
if (isButtonColumnEditor && table.isEditing())
table.getCellEditor().stopCellEditing();
isButtonColumnEditor = false;
}
#Override
public void mouseClicked(MouseEvent e) {
}
#Override
public void mouseEntered(MouseEvent e) {
}
#Override
public void mouseExited(MouseEvent e) {
}
}

The problem isn't the editor. The SPACE key stroke is not forwarded to the default editor in the first column either.
The problem is that JTable defines an Action for the SPACE key so it is intercepted before it has a chance to be passed to the editor. Search my blog for the Key Bindings entry where you will find a program that lists all the default Key Bindings for JTable. The Action that is invoked is called "addToSelection", so I'm not sure why it works differently depending on the row selection.
Anyway one solution is to remove this Action:
InputMap im = table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
KeyStroke space = KeyStroke.getKeyStroke("SPACE");
im.put(space, "none");

Both TableTest, which uses ButtonColumn, and TablePopupEditor are complete examples that work correctly when the Space key is pressed in a selected button cell. Neither evinces the typical ButtonModel-defined appearance of a stand-alone button, but you can provide your own visual queues as required. This related example uses a colored border.

Swing dependent components and event system

I have to build a complex GUI in JAVA with Swing (for the moment I have near 80 classes).
The graphic partv of the application is split as follows: a first series of tabs (eg "Management", "Administration", "Configuration"), then a second level (for example, "User", "Group", "Game"). For now I'm two grade levels (one for each level of tabs). The next level is a JPanel that manages a business object (my whole GUI is built around my business model), at this level there are 2 type of JPanel: who manages simple objects (eg, "User", "Category" , "Game", "Level") and those which manages objects "composite primary key" (eg "User_Game" which represent the form of a double-entry table for each game level for all users).
My second level of tabs can contain multiple JPanel.
When my JPanel manages a single object is composed of a JTable and two buttons (Add and Remove) on which I put events, if not it is a simple JTable. When I have foreign keys (eg "Group" for "User" and "Category" to "Game" or "Level" to "User_Game") it is a JComboBox that takes its information directly from JTableModel. When it comes to managing a JTable object to "composite primary key" the columns and rows also directly dependent models (eg "Game" and "User" "User_Game").
Each has its own JTable model that deals with the persistence layer (Hibernate for information) and other TableModel.
To manage changes (such as adding, modifying or deleting a "User") I use the code below:
import java.awt.event.*;
import javax.swing.*;
import java.beans.*;
/*
* This class listens for changes made to the data in the table via the
* TableCellEditor. When editing is started, the value of the cell is saved
* When editing is stopped the new value is saved. When the oold and new
* values are different, then the provided Action is invoked.
*
* The source of the Action is a TableCellListener instance.
*/
public class TabCellListener implements PropertyChangeListener, Runnable
{
private JTable table;
private Action action;
private int row;
private int column;
private Object oldValue;
private Object newValue;
/**
* Create a TableCellListener.
*
* #param table the table to be monitored for data changes
* #param action the Action to invoke when cell data is changed
*/
public TabCellListener(JTable table, Action action)
{
this.table = table;
this.action = action;
this.table.addPropertyChangeListener( this );
this.table.getModel().addTableModelListener(new ModelListenerTableGui(this.table, this.action));
}
/**
* Create a TableCellListener with a copy of all the data relevant to
* the change of data for a given cell.
*
* #param row the row of the changed cell
* #param column the column of the changed cell
* #param oldValue the old data of the changed cell
* #param newValue the new data of the changed cell
*/
private CellListenerTableGui(JTable table, int row, int column, Object oldValue, Object newValue)
{
this.table = table;
this.row = row;
this.column = column;
this.oldValue = oldValue;
this.newValue = newValue;
}
/**
* Get the column that was last edited
*
* #return the column that was edited
*/
public int getColumn()
{
return column;
}
/**
* Get the new value in the cell
*
* #return the new value in the cell
*/
public Object getNewValue()
{
return newValue;
}
/**
* Get the old value of the cell
*
* #return the old value of the cell
*/
public Object getOldValue()
{
return oldValue;
}
/**
* Get the row that was last edited
*
* #return the row that was edited
*/
public int getRow()
{
return row;
}
/**
* Get the table of the cell that was changed
*
* #return the table of the cell that was changed
*/
public JTable getTable()
{
return table;
}
//
// Implement the PropertyChangeListener interface
//
#Override
public void propertyChange(PropertyChangeEvent e)
{
// A cell has started/stopped editing
if ("tableCellEditor".equals(e.getPropertyName()))
{
if (table.isEditing())
processEditingStarted();
else
processEditingStopped();
}
}
/*
* Save information of the cell about to be edited
*/
private void processEditingStarted()
{
// The invokeLater is necessary because the editing row and editing
// column of the table have not been set when the "tableCellEditor"
// PropertyChangeEvent is fired.
// This results in the "run" method being invoked
SwingUtilities.invokeLater( this );
}
/*
* See above.
*/
#Override
public void run()
{
row = table.convertRowIndexToModel( table.getEditingRow() );
column = table.convertColumnIndexToModel( table.getEditingColumn() );
oldValue = table.getModel().getValueAt(row, column);
newValue = null;
}
/*
* Update the Cell history when necessary
*/
private void processEditingStopped()
{
newValue = table.getModel().getValueAt(row, column);
// The data has changed, invoke the supplied Action
if ((newValue == null && oldValue != null) || (newValue != null && !newValue.equals(oldValue)))
{
// Make a copy of the data in case another cell starts editing
// while processing this change
CellListenerTableGui tcl = new CellListenerTableGui(
getTable(), getRow(), getColumn(), getOldValue(), getNewValue());
ActionEvent event = new ActionEvent(
tcl,
ActionEvent.ACTION_PERFORMED,
"");
action.actionPerformed(event);
}
}
}
And the following action:
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeListener;
import javax.swing.Action;
public class UpdateTableListener<N> extends AbstractTableListener implements Action
{
protected boolean enabled;
public UpdateTableListener(AbstractTableGui<N> obs)
{
super(obs);
this.enabled = true;
}
#Override
public void actionPerformed(ActionEvent e)
{
if (null != e && e.getSource() instanceof CellListenerTableGui)
{
TabCellListener tcl = (TabCellListener)e.getSource();
this.obs.getModel().setValueAt(tcl.getNewValue(), tcl.getRow(), tcl.getColumn());
int sel = this.obs.getModel().getNextRequiredColumn(tcl.getRow());
if (sel == -1)
this.obs.getModel().save(tcl.getRow());
}
}
#Override
public void addPropertyChangeListener(PropertyChangeListener arg0)
{
}
#Override
public Object getValue(String arg0)
{
return null;
}
#Override
public boolean isEnabled()
{
return this.enabled;
}
#Override
public void putValue(String arg0, Object arg1)
{
}
#Override
public void removePropertyChangeListener(PropertyChangeListener arg0)
{
}
#Override
public void setEnabled(boolean arg0)
{
this.enabled = arg0;
}
}
This code works well, data are well persisted.
Then I add this code to refresh dependent components:
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeListener;
import javax.swing.Action;
public class ChangeTableListener implements Action
{
protected AbstractTableGui table;
public ChangeTableListener(AbstractTableGui table)
{
this.table = table;
}
#Override
public void actionPerformed(ActionEvent arg0)
{
this.table.getModel().fireTableDataChanged();
this.table.repaint();
}
#Override
public void addPropertyChangeListener(PropertyChangeListener arg0)
{
}
#Override
public Object getValue(String arg0)
{
return null;
}
#Override
public boolean isEnabled()
{
return false;
}
#Override
public void putValue(String arg0, Object arg1)
{
}
#Override
public void removePropertyChangeListener(PropertyChangeListener arg0)
{
}
#Override
public void setEnabled(boolean arg0)
{
}
}
My TableModel.fireTableDataChanged rebuild JTable content (calle super.fireTableDataChanged and fireTableStructureChanged), JTable.repaint reset the Renderers, and it works for Combobox (forein keys) and it update well title on double-entry tables, but it can't add or delete columns or rows on double-entry tables.
Moreover I see more high latency if there is the slightest change.
My question is simple: how do you manage inter-dependent components?
For your help,
In advance,
Thanks.
Edit :
Here an example of TableCellEditor.
import javax.swing.DefaultCellEditor;
import javax.swing.JTextField;
public class TextColumnEditor extends DefaultCellEditor
{
public TextColumnEditor()
{
super(new JTextField());
}
public boolean stopCellEditing()
{
Object v = this.getCellEditorValue();
if(v == null || v.toString().length() == 0)
{
this.fireEditingCanceled();
return false;
}
return super.stopCellEditing();
}
}
An example of TableModel :
import java.util.ArrayList;
public class GroupModelTable extends AbstractModelTable<Groups>
{
protected GroupsService service;
public GroupModelTable(AbstractTableGui<Groups> content)
{
super(content, new ArrayList<String>(), new ArrayList<Groups>());
this.headers.add("Group");
this.content.setModel(this);
this.service = new GroupsService();
this.setLines(this.service.search(new Groups()));
}
public Object getValueAt(int rowIndex, int columnIndex)
{
switch (columnIndex)
{
case 0:
return this.lines.get(rowIndex).getTitle();
default:
return "";
}
}
public void setValueAt(Object aVal, int rowIndex, int columnIndex)
{
switch (columnIndex)
{
case 0:
this.lines.get(rowIndex).setTitle(aVal.toString());
break;
default:
break;
}
}
#Override
public Groups getModel(int line, int column)
{
return null;
}
#Override
public Groups getModel(int line)
{
return this.lines.get(line);
}
public boolean isCellEditable(int row, int column)
{
return true;
}
#Override
public GroupModelTableGui newLine()
{
this.lines.add(new Groups());
return this;
}
#Override
public int getNextRequiredColumn(int row)
{
Groups g = this.getModel(row);
if (g != null && g.getTitle() != null && g.getTitle().length() > 0)
return -1;
return 0;
}
#Override
public void save(int row)
{
Groups g = this.getModel(row);
if (g != null)
{
try
{
if (g.getId() == null)
this.service.create(g);
else
this.service.update(g);
}
catch (Exception e)
{
}
}
}
#Override
public void removeRow(int row)
{
Groups g = this.getModel(row);
if (g != null)
{
try
{
if (g.getId() != null)
this.service.delete(g);
super.removeRow(row);
}
catch (Exception e)
{
}
}
}
}
An example of Table :
public class GroupTable extends AbstractTable<Groups>
{
public GroupTable()
{
new GroupModelTableGui(this);
new CellListenerTableGui(this.getContent(), new UpdateTableListenerGui<Groups>(this));
this.getContent().getColumnModel().getColumn(0).setCellEditor(new TextColumnEditorGui());
}
}
I hope it will help you to understand :/

Your TabCellListener is unfamiliar to me. Your TableCellEditor should not interact with the TableModel directly. It should implement getTableCellEditorComponent() and getCellEditorValue(), as shown in this example. When the editor concludes, the model will have the new value. Your TableModel should handle persistence. More than one view may listen to a single TableModel via TableModelListener.
Addendum: Your CellEditor, TextColumnEditor, probably shouldn't invoke fireEditingCanceled(). Pressing Escape should be sufficient to revert the edit, as shown in this example. You might also look at the related tutorial section and example.

How to UnFocus a JTextField

When my application loads, which is made using netbeans, the first JTextField is automatically focused, and in this JTextField, I have written "Enter your Username", it will go away when the user clicks on this field, but when the application is loaded, this field is focused, means I can't see "Enter your Username", how to unfocus it on startup ?

A log-in would be best done in a modal dialog, but that introduces problems in that the method requestFocusInWindow() must be called after the component is visible, but that is blocked by the fact the dialog is modal!
This example uses Rob Camick's RequestFocusListener (as presented in Dialog Focus) to manage focus after the dialog is visible.
Note: That is how it appears before the user does anything. The password field is focused by default.
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
public class LoginRequired {
LoginRequired() {
JFrame f = new JFrame("Login Required");
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setResizable(false);
f.setSize(400, 300); // not recommended, but used here for convenience
f.setLocationByPlatform(true);
f.setVisible(true);
showLogin(f);
}
private void showLogin(JFrame frame) {
JPanel p = new JPanel(new BorderLayout(5,5));
JPanel labels = new JPanel(new GridLayout(0,1,2,2));
labels.add(new JLabel("User Name", SwingConstants.TRAILING));
labels.add(new JLabel("Password", SwingConstants.TRAILING));
p.add(labels, BorderLayout.LINE_START);
JPanel controls = new JPanel(new GridLayout(0,1,2,2));
JTextField username = new JTextField("Joe Blogs");
controls.add(username);
JPasswordField password = new JPasswordField();
password.addAncestorListener(new RequestFocusListener(false));
controls.add(password);
p.add(controls, BorderLayout.CENTER);
JOptionPane.showMessageDialog(
frame, p, "Log In", JOptionPane.QUESTION_MESSAGE);
System.out.println("User Name: " + username.getText());
System.out.println("Password: " + new String(password.getPassword()));
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
new LoginRequired();
});
}
}
/**
* Convenience class to request focus on a component.
*
* When the component is added to a realized Window then component will
* request focus immediately, since the ancestorAdded event is fired
* immediately.
*
* When the component is added to a non realized Window, then the focus
* request will be made once the window is realized, since the
* ancestorAdded event will not be fired until then.
*
* Using the default constructor will cause the listener to be removed
* from the component once the AncestorEvent is generated. A second constructor
* allows you to specify a boolean value of false to prevent the
* AncestorListener from being removed when the event is generated. This will
* allow you to reuse the listener each time the event is generated.
*/
class RequestFocusListener implements AncestorListener
{
private boolean removeListener;
/*
* Convenience constructor. The listener is only used once and then it is
* removed from the component.
*/
public RequestFocusListener()
{
this(true);
}
/*
* Constructor that controls whether this listen can be used once or
* multiple times.
*
* #param removeListener when true this listener is only invoked once
* otherwise it can be invoked multiple times.
*/
public RequestFocusListener(boolean removeListener)
{
this.removeListener = removeListener;
}
#Override
public void ancestorAdded(AncestorEvent e)
{
JComponent component = e.getComponent();
component.requestFocusInWindow();
if (removeListener)
component.removeAncestorListener( this );
}
#Override
public void ancestorMoved(AncestorEvent e) {}
#Override
public void ancestorRemoved(AncestorEvent e) {}
}

textField.setFocusable(false);
textField.setFocusable(true);
If, and only if, textField had focus, the next component in TAB-order order will get focus automatically. The effect is the same as a TAB press.
(not tested in a GUI with just one focusable component :) )

Use requestFocusInWindow() to set focus on some other component rather then your JTextfield first.
But i'd suggest not to alter the native focus system, rather setText(String s) on the JTextField after initComponents() call in the constructor (assumed to be in netbeans).
Further optional reading: How to Use the Focus Subsystem

I think giving keyboard focus to the username field is the correct behavior, assuming that's what the user needs to do first. Instead of clearing on focus, why not clear only after the user types something?:
import java.awt.*;
import javax.swing.*;
import javax.swing.text.Document;
public class PlaceholderTextField extends JTextField {
public static void main(final String[] args) {
final PlaceholderTextField tf = new PlaceholderTextField("");
tf.setColumns(20);
tf.setPlaceholder("All your base are belong to us!");
final Font f = tf.getFont();
tf.setFont(new Font(f.getName(), f.getStyle(), 30));
JOptionPane.showMessageDialog(null, tf);
}
private String placeholder;
public PlaceholderTextField() {
}
public PlaceholderTextField(
final Document pDoc,
final String pText,
final int pColumns)
{
super(pDoc, pText, pColumns);
}
public PlaceholderTextField(final int pColumns) {
super(pColumns);
}
public PlaceholderTextField(final String pText) {
super(pText);
}
public PlaceholderTextField(final String pText, final int pColumns) {
super(pText, pColumns);
}
public String getPlaceholder() {
return placeholder;
}
#Override
protected void paintComponent(final Graphics pG) {
super.paintComponent(pG);
if (placeholder.length() == 0 || getText().length() > 0) {
return;
}
final Graphics2D g = (Graphics2D) pG;
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.setColor(getDisabledTextColor());
g.drawString(placeholder, getInsets().left, pG.getFontMetrics()
.getMaxAscent() + getInsets().top);
}
public void setPlaceholder(final String s) {
placeholder = s;
}
}
If you really just want to remove focus, some options:
component.setFocusable(false);
KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent();
KeyboardFocusManager.getCurrentKeyboardFocusManager().clearGlobalFocusOwner();

Can i use JCheckbox to show "mixed state"

In windows it is possible to show a grayed out JCheckbox, to show that the collection of data which it represents not all items have the same value.
Is this even possible with a JCheckBox?
How do i go about this?
(Hoping there's a way to not override it)
Thanks

JIDE Common Layer has a TristateCheckBox.

It's possible with some of work.
I have this code from some years ago. Is based in some examples I found in internet, but I cannot find any reference to the original creator, so I apologize
import javax.swing.*;
import javax.swing.event.ChangeListener;
import javax.swing.plaf.ActionMapUIResource;
import java.awt.event.*;
/**
* Maintenance tip - There were some tricks to getting this code
* working:
*
* 1. You have to overwite addMouseListener() to do nothing
* 2. You have to add a mouse event on mousePressed by calling
* super.addMouseListener()
* 3. You have to replace the UIActionMap for the keyboard event
* "pressed" with your own one.
* 4. You have to remove the UIActionMap for the keyboard event
* "released".
* 5. You have to grab focus when the next state is entered,
* otherwise clicking on the component won't get the focus.
* 6. You have to make a TristateDecorator as a button model that
* wraps the original button model and does state management.
*/
public class TristateCheckBox extends JCheckBox {
/** This is a type-safe enumerated type */
public static class State { private State() { } }
public static final State NOT_SELECTED = new State();
public static final State SELECTED = new State();
public static final State DONT_CARE = new State();
private final TristateDecorator model;
public TristateCheckBox(String text, Icon icon, State initial){
super(text, icon);
// Add a listener for when the mouse is pressed
super.addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
grabFocus();
model.nextState();
}
});
// Reset the keyboard action map
ActionMap map = new ActionMapUIResource();
map.put("pressed", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
grabFocus();
model.nextState();
}
});
map.put("released", null);
SwingUtilities.replaceUIActionMap(this, map);
// set the model to the adapted model
model = new TristateDecorator(getModel());
setModel(model);
setState(initial);
}
public TristateCheckBox(String text, State initial) {
this(text, null, initial);
}
public TristateCheckBox(String text) {
this(text, DONT_CARE);
}
public TristateCheckBox() {
this(null);
}
/** No one may add mouse listeners, not even Swing! */
public void addMouseListener(MouseListener l) { }
/**
* Set the new state to either SELECTED, NOT_SELECTED or
* DONT_CARE. If state == null, it is treated as DONT_CARE.
*/
public void setState(State state) { model.setState(state); }
/** Return the current state, which is determined by the
* selection status of the model. */
public State getState() { return model.getState(); }
public void setSelected(boolean b) {
if (b) {
setState(SELECTED);
} else {
setState(NOT_SELECTED);
}
}
/**
* Exactly which Design Pattern is this? Is it an Adapter,
* a Proxy or a Decorator? In this case, my vote lies with the
* Decorator, because we are extending functionality and
* "decorating" the original model with a more powerful model.
*/
private class TristateDecorator implements ButtonModel {
private final ButtonModel other;
private TristateDecorator(ButtonModel other) {
this.other = other;
}
private void setState(State state) {
if (state == NOT_SELECTED) {
other.setArmed(false);
setPressed(false);
setSelected(false);
} else if (state == SELECTED) {
other.setArmed(false);
setPressed(false);
setSelected(true);
} else { // either "null" or DONT_CARE
other.setArmed(true);
setPressed(true);
setSelected(true);
}
}
/**
* The current state is embedded in the selection / armed
* state of the model.
*
* We return the SELECTED state when the checkbox is selected
* but not armed, DONT_CARE state when the checkbox is
* selected and armed (grey) and NOT_SELECTED when the
* checkbox is deselected.
*/
private State getState() {
if (isSelected() && !isArmed()) {
// normal black tick
return SELECTED;
} else if (isSelected() && isArmed()) {
// don't care grey tick
return DONT_CARE;
} else {
// normal deselected
return NOT_SELECTED;
}
}
/** We rotate between NOT_SELECTED, SELECTED and DONT_CARE.*/
private void nextState() {
State current = getState();
if (current == NOT_SELECTED) {
setState(SELECTED);
} else if (current == SELECTED) {
setState(DONT_CARE);
} else if (current == DONT_CARE) {
setState(NOT_SELECTED);
}
}
/** Filter: No one may change the armed status except us. */
public void setArmed(boolean b) {
}
/** We disable focusing on the component when it is not
* enabled. */
public void setEnabled(boolean b) {
setFocusable(b);
other.setEnabled(b);
}
/** All these methods simply delegate to the "other" model
* that is being decorated. */
public boolean isArmed() { return other.isArmed(); }
public boolean isSelected() { return other.isSelected(); }
public boolean isEnabled() { return other.isEnabled(); }
public boolean isPressed() { return other.isPressed(); }
public boolean isRollover() { return other.isRollover(); }
public void setSelected(boolean b) { other.setSelected(b); }
public void setPressed(boolean b) { other.setPressed(b); }
public void setRollover(boolean b) { other.setRollover(b); }
public void setMnemonic(int key) { other.setMnemonic(key); }
public int getMnemonic() { return other.getMnemonic(); }
public void setActionCommand(String s) {
other.setActionCommand(s);
}
public String getActionCommand() {
return other.getActionCommand();
}
public void setGroup(ButtonGroup group) {
other.setGroup(group);
}
public void addActionListener(ActionListener l) {
other.addActionListener(l);
}
public void removeActionListener(ActionListener l) {
other.removeActionListener(l);
}
public void addItemListener(ItemListener l) {
other.addItemListener(l);
}
public void removeItemListener(ItemListener l) {
other.removeItemListener(l);
}
public void addChangeListener(ChangeListener l) {
other.addChangeListener(l);
}
public void removeChangeListener(ChangeListener l) {
other.removeChangeListener(l);
}
public Object[] getSelectedObjects() {
return other.getSelectedObjects();
}
}
}

My colleague who this question came from thought of this;
Create a dummy JCheckBox which is disabled and selected. set the same size as the real one.
Create an Icon which' paint method actually paints the dummy JCheckbox.
Set the original JCheckBox' Icon to the one painting the dummy.
Remove the icon as soon as the JCheckBox is clicked.
++ No overridden JCheckBox
-- not a real tri-state Combo
I think he's satisfied.
Thanks for the help