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Guest

I have a JTable with editable columns, some of which should accept only
numbers. To do this, I have added a DefaultCellEditor to the numeric
columns, with a JTextField to accept user input, and a KeyListener to
filter out non-numeric keystrokes from the JTextField.

The user can start editing by mouse-clicking in a cell and typing, or
by navigating around the table using the arrow keys, then type in a
cell, without using the mouse.

All this works well, except in the second case when the user types in a
cell without first selecting it with the mouse. The problem here is
that the KeyListener does not see the first keystroke, but does see
subsequent ones. That means one non-numeric character can be entered
into the cell. However, the KeyListener always works if the user first
selects the cell with a mouse-click. Below is some code showing this
behaviour. What am I missing? How can I capture that first keystroke? I
am using Java 1.5.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;

public class Test extends JFrame {
public Test() {
JTable table = new JTable(new Object[][] { {"a",1,2},{"b",3,4} },
new String[] {"Text", "Num 1", "Num 2"});
table.setRowSelectionAllowed(false);
table.setSurrendersFocusOnKeystroke(true);

TableColumnModel cm = table.getColumnModel();
cm.getColumn(1).setCellEditor(new MyCellEditor());
cm.getColumn(2).setCellEditor(new MyCellEditor());

JScrollPane scrollPane = new JScrollPane(table);
getContentPane().add(scrollPane);
}

private class MyCellEditor extends DefaultCellEditor {
private final JTextField tf;

public MyCellEditor() {
super(new JTextField());
tf = (JTextField) getComponent();
tf.addKeyListener(new MyKeyListener ());
setClickCountToStart(1);
}

public Component getTableCellEditorComponent(JTable table,
Object value, boolean isSelected, int row, int column) {
tf.setText(value.toString());
return tf;
}

public Object getCellEditorValue() {
return tf.getText();
}
}

private class MyKeyListener implements KeyListener {
public void keyPressed(KeyEvent e) {}
public void keyReleased(KeyEvent e) {}
public void keyTyped(KeyEvent e) {
if ( ! Character.isDigit(e.getKeyChar()) ) {
Toolkit.getDefaultToolkit().beep();
e.consume();
}
}
}

public static void main(String[] args) {
Test frame = new Test();
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}

Mike

Vova Reznik · Guest

michael.o'connor (AT) bluescopesteel (DOT) com wrote:

bparanj · Guest

import java.awt.Component;

import javax.swing.JTable;
import javax.swing.table.TableCellEditor;
import javax.swing.table.TableModel;
import javax.swing.text.JTextComponent;

public class MyTable extends JTable {

public MyTable(TableModel dm) {
super(dm);
}

public Component prepareEditor(TableCellEditor editor,int row,int col)
{
JTextComponent comp = (JTextComponent)super.prepareEditor(editor,
row, col);
comp.setText(null);

return comp;
}

}

This code works. Do I need to provide other methods and delegate the
calls to JTable? Thanks.
BP
http://www.ProblemSolvingSkill.net

Vova Reznik · Guest

bparanj wrote:

bparanj · Guest

Thanks. Actually two of my cells in my table allow numeric or hyphen
characters only. So I have been experimenting with your code. It seems
like that since the default implementation of JTable does not provide
the validation that checks if the entered value is numeric or hyphen, I
have to write my own custom editor right?

So if I do that, I am back to square one again. It is showing the first
character even if is not a legal character and then it starts beeping
and prevents entering of illegal characters. How do I resolve this
issue? Thanks for your time again!

BP
http://www.ProblemSolvingSkill.net

Vova Reznik · Guest

bparanj wrote:

Vova Reznik · Guest

bparanj wrote:

steve · Guest

On Fri, 26 May 2006 00:25:37 +0800, bparanj wrote
(in article <1148574337.708553.261140 (AT) j73g2000cwa (DOT) googlegroups.com>):

bparanj · Guest

Thank you Steve. I actually got some ideas from the Sun Swing forum.
The following code is based on that:

package swing.table;

import java.awt.Component;

import javax.swing.JTable;
import javax.swing.table.TableCellEditor;
import javax.swing.table.TableModel;
import javax.swing.text.JTextComponent;

import client.EditorState;

public class MyTable extends JTable {

public MyTable(TableModel dm) {
super(dm);
}

public Component prepareEditor(TableCellEditor editor, int row, int
col) {
//If the cell is JComboBox then default behaviour is same as
super class.
if(col == 2) {
return super.prepareEditor(editor, row, col);
}

JTextComponent comp = (JTextComponent)
super.prepareEditor(editor, row, col);
//The setText method makes the old value disappear when a user
starts typing in a
// cell
if(!EditorState.getInstance().isRestoreInProgress()) {
comp.setText(null);
}

return comp;
}
}

This table allows the selection of cells in a table. This works fine in
most cases. The problem is that when I select a particular cell in a
table and open another table to display the data, it copies the value
of the old table's cell into the newly opened table cell.

How do I avoid this unwanted copy of old data? Thanks in advance.

BP
http://www.ProblemSolvingSkill.net