Develop Reference

How to give keyboard focus to Custom panel in JTable?

I am working on making the Arduino IDE fully accessible for people using access software. This means adding keyboard accessibility to two of the dialogs that currently do not work with access software under windows. The two dialogs are the Board Manager and the LibraryManager. If you want a real example of what I am posting you can get teh Arduino IDE on the Windows Store or download it on line. Just search for Arduino IDE and download the windows version. .
doing all that might be to much for most of you so I have created a more simple table that shows the same problem. If someone can help me understand how to add keyboard and focus access to the below Custom JTable and its custom column which is a JPanel I can work on fixing the Arduino IDE tables.
I understand that the Arduino IDE should probably be made into a
better table but I have yet to figure out a cleaner way to do what they are doing with these tables so I am trying to make what they have accessible.
So below is my problem table. It has two rows and two columsn. The
second column of each row is a panel of controls. I have borrowed
this code from some other stack posts and modified it to fit my
question. So if you think you have seen some of this code before that
is why. The problem is the code works for a mouse. At least I think
it does because I am blind and can not select the controls on the
second column because they can not get keyboard focus.
So Can someone out there help me figure out how to get keyboard focus
to move through this entire table. I have tried using focus
listeners, keyboard listeners, Focus Traversal policies, property
changes, and combinations between all of the above. I have taken out
my terrible attempts. Swing really should work without having to do
all this extra work but Java is what java is.
So if you are great at Java with swing please put away your mouse and run this
code and see if you can make the buttons activate without the mouse.
If you can and you can explain to me how to do it many blind users will
be in your debt.
Note that you should be able to Shift+Control+tab tot he table if the table is not the only control. On my sample it is. Then you should be able to arrow through the rows and columns and tab and shift+tab through the controls on the JPanel.
You can get the zip group of these files if you don't want to
put this all together yourself at this dropbox link:
https://www.dropbox.com/s/h4bdfu1mlo0jsvr/TableAccessTest.zip?dl=0
Here is the files. Each class has a comment with the file name before it. Again get the zip if you don't want to play block and copy.
//TableAccessTest.java
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.TableCellEditor;
public class TableAccessTest extends JPanel
{
TableModel customRendererEditorTableModel = new TableModel();
JTable table;
public TableAccessTest()
{
setLayout(new BorderLayout());
table = new JTable(customRendererEditorTableModel);
table.setPreferredScrollableViewportSize(new Dimension(500, 600));
table.setRowSelectionAllowed(false);
table.setRowHeight(300);
table.getColumn("Custom JPanel").setCellRenderer(new CustomJPanelRenderer());
table.getColumn("Custom JPanel").setCellEditor(new CustomJPanelEditor());
JScrollPane scrollPane = new JScrollPane(table);
add(scrollPane);
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("Custom JPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComponent newContentPane = new TableAccessTest();
newContentPane.setOpaque(true);
frame.setContentPane(newContentPane);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args)
{
javax.swing.SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}
//CustomJPanel.java
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.*;
public class CustomJPanel extends JPanel
{
JPanel colorPanel = new JPanel(new BorderLayout());
JButton jButton = new JButton("Change Color");
JSlider jSlider = new JSlider(JSlider.VERTICAL);
JTextField jTextField = new JTextField("");
public CustomJPanel()
{
jButton.setOpaque(true);
jButton.setFocusable(true);
jTextField.setEditable(false);
jTextField.setFocusable(true);
setFocusable(true);
jButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
Random randomGenerator = new Random();
int randomInt = randomGenerator.nextInt(4);
switch (randomInt)
{
case (0):
colorPanel.setBackground(Color.BLUE);
jTextField.setText("blue");
break;
case (1):
colorPanel.setBackground(Color.BLACK);
jTextField.setText("black");
break;
case (2):
colorPanel.setBackground(Color.CYAN);
jTextField.setText("cyan");
break;
default:
colorPanel.setBackground(Color.GREEN);
jTextField.setText("green");
break;
}
}
});
jSlider.setOpaque(true);
setLayout(new BorderLayout());
add(colorPanel, BorderLayout.CENTER);
add(jButton, BorderLayout.SOUTH);
add(jTextField, BorderLayout.NORTH);
add(jSlider, BorderLayout.EAST);
}
}
//TableModel.java
import javax.swing.table.AbstractTableModel;
public class TableModel extends AbstractTableModel
{
private String[] columnNames =
{
"First Column",
"Custom JPanel",
};
private Object[][] data =
{
{"Foo", new CustomJPanel()},
{"Bar", new CustomJPanel()}
};
public int getColumnCount()
{
return columnNames.length;
}
public int getRowCount()
{
return data.length;
}
public String getColumnName(int col)
{
return columnNames[col];
}
public Object getValueAt(int row, int col)
{
return data[row][col];
}
public Class getColumnClass(int c)
{
return getValueAt(0, c).getClass();
}
public boolean isCellEditable(int row, int col)
{
return col >= 1;
}
public void setValueAt(Object value, int row, int col)
{
data[row][col] = value;
fireTableCellUpdated(row, col);
}
}
//CustomJPanelEditor.java
import javax.swing.AbstractCellEditor;
import javax.swing.JTable;
import javax.swing.table.TableCellEditor;
public class CustomJPanelEditor extends AbstractCellEditor implements TableCellEditor
{
CustomJPanel customJPanel;
public CustomJPanelEditor()
{
customJPanel = new CustomJPanel();
}
#Override
public java.awt.Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column)
{
customJPanel = (CustomJPanel) value;
return customJPanel;
}
#Override public Object getCellEditorValue()
{
return customJPanel;
}
}
//CustomJPanelRenderer.java
import javax.swing.JTable;
import javax.swing.table.TableCellRenderer;
public class CustomJPanelRenderer implements TableCellRenderer
{
CustomJPanel rendererJPanel;
public CustomJPanelRenderer()
{
rendererJPanel = new CustomJPanel();
}
#Override
public java.awt.Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column)
{
rendererJPanel = (CustomJPanel) value;
return rendererJPanel;
}
}

How do I declare a JComboBox?

I was creating a program to work with a drop-down list, but I got stuck at the line of declaration of JComboBox box, I get these error messages:
Multiple markers at this line
- The constructor JComboBox(String[]) is
undefined
- Line breakpoint:JComboBox [line: 25] -
JComboBox()
No matter how I try to define JComboBox, I get some sort of error. Please help me with it.
Here's the code of the public class:
import javax.swing.*;
import java.awt.FlowLayout;
import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JRadioButton;
import javax.swing.ButtonGroup;
import java.awt.event.ItemListener;
import java.awt.event.ItemEvent;
public class JComboBox extends JFrame {
private JComboBox box;
private JLabel picture;
private static String[] filename = { "p.png", "i.png" };
private Icon pics[] = { new ImageIcon(getClass().getResource(filename[0])),
new ImageIcon(getClass().getResource(filename[1])) };
public JComboBox() {
super("This is the title");
setLayout(new FlowLayout());
JComboBox box = new JComboBox(filename);
box.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent event) {
if (event.getStateChange() == ItemEvent.SELECTED) {
picture.setIcon(pics[box.getSelectedIndex()]);
}
}
});
add(box);
picture = new JLabel(pics[0]);
add(picture);
}
}
And here's the code of the main class:
import javax.swing.*;
public class JComboBox1 extends JFrame {
public static void main(String[] args) {
JComboBox Box = new JComboBox();
Box.setVisible(true);
Box.setSize(400,400);
Box.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Thank you.

Your problem, as #Andy mentioned is that you have a collision in the name of your class and the swing component. If you absolutely must name your class JComboBox you'll have to reference the swing component by the fully-qualified name, as such
public class JComboBox extends JFrame {
private javax.swing.JComboBox box;
If you hover over your private instance with an IDE you should see the fully-qualified name matching the package in which you've created your JComboBox class. Save yourself some pain and rename your class.

Adding values to Jtable when button is clicked in java [duplicate]

In my application everything is distributed.
On a action, application retrieves data from DB and saves in ArrayList<T>.
I create an object of RelativeTableModel where I pass the ArrayList<T>.
public void RelationsClicked() {
ArrayList<Relation> data = myParent.dbOperation.getRelations();
RelativeTableModel tModel = new RelativeTableModel(data); // subclass of AbstractTableModel
myParent.SetBrowsePanelData(tModel);
myParent.SetMainPanel(CashAccountingView.BROWSEPANEL);
}
I have a BrowseListPanel class that has a JTable in JScrollPane. Its instance is already created in the main application.
I pass the model to BrowseListPanel and finally show the panel.
Code:
public void SetBrowsePanelData(AbstractTableModel tModel) {
browsePanel.setTModel(tModel);
}
// BrowseListPanel's Code
public void setTModel(AbstractTableModel tModel) {
this.tModel = tModel; // tModel = AbstractTableModel
}
// Show the Panel
public void SetMainPanel(String panel) {
activePanel = panel;
SetFontSize();
cards.show(mainPanel, panel);
mainPanel.revalidate();
mainPanel.repaint();
}
But I don't see the Table. I believe as the object of BrowseListPanel (containing the JTable) is already created & later the TableModel is added. So some sort of event should be fired in setTModel().
Am I right? If so, what event should be thrown and what should be its implementation.

Invoking setModel() on the table should be sufficient, but you might call fireTableStructureChanged() on the model explicitly as a way to help sort things out.
Also, verify that you are working on the event dispatch thread.
Addendum: Here's an sscce that shows the basic approach.
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
/** #see http://stackoverflow.com/questions/8257148 */
public class SwapTableModel extends JPanel {
public SwapTableModel() {
final JTable table = new JTable(Model.Alpha.model);
table.setPreferredScrollableViewportSize(new Dimension(128, 32));
this.add(new JScrollPane(table));
final JComboBox combo = new JComboBox();
for (Model model : Model.values()) {
combo.addItem(model);
}
this.add(combo);
combo.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Model model = (Model) combo.getSelectedItem();
table.setModel(model.model);
}
});
}
private enum Model {
Alpha(), Beta();
private DefaultTableModel model;
private Model() {
Object[] data = {this.toString()};
this.model = new DefaultTableModel(data, 1);
model.addRow(data);
}
}
private void display() {
JFrame f = new JFrame("SwapTableModel");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new SwapTableModel().display();
}
});
}
}

Making a JTextField with Vanishing Text

I am familiar that you can input text before hand into a JTextField. This text will be displayed in the JTextField and has to be manually deleted when having to input your own text into the JTextField. For example, consider this JTextField:
cruiseSel = new JTextField ("Selected Cruise:");
cruiseSel.setEditable(false);
centerP12.add(cruiseSel);
contentPane12.add(centerP12, BorderLayout.CENTER);
Frame12.setVisible(true);
Upon running the above, a JTextField will appear with "Selected Cruise:" written within it. This text then has to be manually deleted to clear the text field.
Is there a way to input text in an JTextField, so once the GUI opens, the text will be displayed, but when the JTextField is selected to input manual text, the text vanishes?

You could use a FocusListener and when the JTextField receives focus, empty the text.
Of course you will want a state marker to indicate it has the default text and not do this once you have user entered text. Either that or after the FocusListener is hit the first time, remove it.
textField.addFocusListener(new FocusAdapter() {
public void focusGained(FocusEvent e) {
JTextField source = (JTextField)e.getComponent();
source.setText("");
source.removeFocusListener(this);
}
});

What you are looking for is called placeholder. I've written this class a while ago:
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
/**
* #author xehpuk
*/
public class PlaceholderTextField extends JTextField {
private static final long serialVersionUID = -5529071085971698388L;
/**
* The placeholder to be displayed if the text field is empty.
*/
private String placeholder;
/**
* Determines whether the placeholder should be displayed even on focus.
*/
private boolean paintingOnFocus;
/**
* The color the placeholder should be displayed in.
*/
private Color placeholderColor;
public String getPlaceholder() {
return placeholder;
}
public void setPlaceholder(final String placeholder) {
this.placeholder = placeholder;
repaint();
}
public boolean isPaintingOnFocus() {
return paintingOnFocus;
}
public void setPaintingOnFocus(final boolean paintingOnFocus) {
this.paintingOnFocus = paintingOnFocus;
repaint();
}
public Color getPlaceholderColor() {
return placeholderColor;
}
public void setPlaceholderColor(final Color placeholderColor) {
this.placeholderColor = placeholderColor;
repaint();
}
public PlaceholderTextField() {
super();
}
public PlaceholderTextField(final Document doc, final String text, final int columns) {
super(doc, text, columns);
}
public PlaceholderTextField(final int columns) {
super(columns);
}
public PlaceholderTextField(final String text, final int columns) {
super(text, columns);
}
public PlaceholderTextField(final String text) {
super(text);
}
{
addFocusListener(new RepaintFocusListener());
}
#Override
protected void paintComponent(final Graphics g) {
super.paintComponent(g);
if (getPlaceholder() != null && getText().isEmpty() && (isPaintingOnFocus() || !isFocusOwner())) {
try {
final Rectangle rect = getUI().modelToView(this, 0);
final Insets insets = getInsets();
g.setFont(getFont());
g.setColor(getPlaceholderColor() == null ? getForeground() : getPlaceholderColor());
((Graphics2D) g).setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g.drawString(getPlaceholder(), rect.x, getHeight() - insets.top - insets.bottom - rect.y);
} catch (final BadLocationException e) {
throw new RuntimeException(e);
}
}
}
private class RepaintFocusListener implements FocusListener {
#Override
public void focusGained(final FocusEvent e) {
repaint();
}
#Override
public void focusLost(final FocusEvent e) {
repaint();
}
}
}
You can choose the text and the color and whether it should be painted even if the text field has focus.
The crucial part is the overriding of paintComponent(Graphics).

You can use SwingX Read on this How to set Text like Placeholder in JTextfield in swing
I include the sample code here for your use
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import org.jdesktop.swingx.prompt.PromptSupport;
public class PromptExample {
public static void main(String[] args) {
new PromptExample();
}
public PromptExample() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JTextField bunnies = new JTextField(10);
JTextField ponnies = new JTextField(10);
JTextField unicorns = new JTextField(10);
JTextField fairies = new JTextField(10);
PromptSupport.setPrompt("Bunnies", bunnies);
PromptSupport.setPrompt("Ponnies", ponnies);
PromptSupport.setPrompt("Unicorns", unicorns);
PromptSupport.setPrompt("Fairies", fairies);
PromptSupport.setFocusBehavior(PromptSupport.FocusBehavior.HIDE_PROMPT, bunnies);
PromptSupport.setFocusBehavior(PromptSupport.FocusBehavior.HIGHLIGHT_PROMPT, ponnies);
PromptSupport.setFocusBehavior(PromptSupport.FocusBehavior.SHOW_PROMPT, unicorns);
PromptSupport.setFontStyle(Font.BOLD, bunnies);
PromptSupport.setFontStyle(Font.ITALIC, ponnies);
PromptSupport.setFontStyle(Font.ITALIC | Font.BOLD, unicorns);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
frame.add(bunnies, gbc);
frame.add(ponnies, gbc);
frame.add(unicorns, gbc);
frame.add(fairies, gbc);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}

Check out Text Prompt.
It supports this functionality along with a couple of features to customize the behaviour of the prompt.

To achieve something like this, you would generally need to create a certain type of event listener. In your case, the desired action needs to be triggered on a mouse event - thus the MouseAdapter event listener seems like a good fit (at first glance). To use the MouseAdapter
abstract class, you'd need to extend it and override the necessary methods (see here for a full list of available methods).
The shortest way of achieving this is via an anonymous class declaration, like so:
cruiseSel.addMouseListener(new MouseAdapter(){
#Override
public void mouseClicked(MouseEvent e){
cruiseSel.setText("");
}
});
(However, if you need to override multiple methods or the triggered logic feels complex enough, you might be better off creating a separate listener class.)
EDIT: Alternatively, as #HovercraftFullOfEels pointed out in the comment section, it would probably be wiser to apply the FocusAdapter class (see here) in an identical fashion:
cruiseSel.addFocusListener(new FocusAdapter(){
#Override
public void focusGained(FocusEvent e){
cruiseSel.setText("");
}
});
The problem with the first solution is that it is only concerned with listening for actual MOUSE CLICKS on the text field, while the latter listens for ANY types of focus-gains on it. Thus, when using the TAB key to switch between text fields, only the second solution would perform correctly.

JTable add/remove rows to custom table model (updating table display)

Does anyone have a good example of how to Add/Remove rows from a JTable using a custom table model? The issue I seem to be having is how to have the table keep updating when I add or remove items.
The real simple idea here is to have an add and remove button above my table which allows the user on the fly to change the table.

Here is example for adding row:
import java.awt.BorderLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.util.Vector;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.JViewport;
import javax.swing.SwingUtilities;
import javax.swing.table.AbstractTableModel;
public class RowAdder extends JFrame {
final SimpleModel tableData = new SimpleModel();
JTable table = new JTable(tableData);
public static void main(String[] args) {
RowAdder ra = new RowAdder();
ra.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ra.setSize(400, 300);
ra.setVisible(true);
}
public RowAdder() {
final JTextField textField = new JTextField();
setLayout(new BorderLayout());
add(new JScrollPane(table), BorderLayout.CENTER);
textField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
tableData.addText(textField.getText());
textField.setText("");
}
});
add(textField, BorderLayout.SOUTH);
}
}
class SimpleModel extends AbstractTableModel {
Vector textData = new Vector();
public void addText(String text) {
textData.addElement(text);
fireTableDataChanged();
}
public int getRowCount() {
return textData.size();
}
public int getColumnCount() {
return 3;
}
public Object getValueAt(int row, int column) {
return textData.elementAt(row);
}
}
above ref from : http://www.java2s.com/Tutorial/Java/0240__Swing/AddrowstoaTable.htm
Checkout this tutorial about JTable:
http://download.oracle.com/javase/tutorial/uiswing/components/table.html
Specifically for table model check:
http://download.oracle.com/javase/tutorial/uiswing/components/table.html#data
I think this tutorial should answer all your question.

You have to notify the JTable object on changes of the underlying table model. The table is not observing the model but waiting for events.
After every change (or set of changes), create a TableModelEvent and call the tables tableChanged method.