Return to the cell after data validation in JTable

Question

Hi,
I am implementing an editable JTable. I want the focus or selection return to the current editing cell when the user inputing a wrong format data. I can catch the validation error and pop up a error message to user. But I can not return the focus or selection to the editing cell.
If anyone has already solved this problem, please give me your solution.
Thank you!
I have tried:
1.
In tableChanged(TableModelEvent e) method:
int row = e.getFirstRow();
int column = e.getColumn();
Object data = newJTable.getValueAt(row, column);
if(!validation(data)) // return true if validation OK
editFailed = true;//class variable
previousRow = row;//class variable
previousCol = column;//class variable
Add a focus listener to the table and implement the focus listener's focusLost method with:
if(validationFailed)
table.editCellAt(previousRow, previousCol);
This does move the focus to the editing cells if you want to continue to edit the table.
Problems are
If you move the focus out of the table, the wrong date will be in the table or not edited.
The selection color was shown on the next cell where you pointed your mouse to after you leave the editing cells.
2. I have also tried to use:
in the above focusLost method
table.clearSelection();
table.editCellAt(previousRow, previousCol);
table.setRowSelectionInterval(previousRow, previousRow);
table.setColumnSelectionInterval(previousCol, previousRow);
But it did not change the selection.
Shaolong

Answer 1

This is the fix for the above problem.
Basically we need to handle both mouse/keyboard actions on our own.
This code returns the control to errorCell..
/* TableCellValidator class */
/* The class basically validates the input entry in a cell and */
/* pops up a JOptionPane if its an invalid input */
/* And an OK is clicked on the JOptionPane, the control returns back */
/* to the same cell */
/* Basic Idea: The controls Arrow/Tab/mouse clicks are handled by our */
/* ----------- custom table. Its has been slightly tricky to handle */
/* mouse clicks, since when you click the next cell, the */
/* editingrow/editingcol advances. Hence the */
/* previousrow/previouscol has been captured in the */
/* setValueAt method. */
/* To capture Table/Arrow/Numeric Arrow, The keyStrokes(TAB etc)*/
/* assigned different AbstractionActions to execute like */
/* validateBeforeTabbingToNextCell */
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
public class TableCellValidator {
* Constructor.
* Basically instantiates the class and sets up the
* JFrame object and the table.
public TableCellValidator() {
JFrame f = new JFrame("JTable test");
f.getContentPane().add(new JScrollPane(createTable()), "Center");
f.pack();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
* A method which created our custom table.
* The JTable methods processMouseEvent
* and setValueAt are overridden to handle
* Mouseclicks.
* The Tables ActionMap is fed with different
* AbstractAction classes eg: (validateBeforeTabbingToNextCell)
* (Scroll down below for the innerclass
* validateBeforeTabbingToNextCell).
* So basically when TAB is pressed the stuff present
* in the validateBeforeTabbingToNextCell's actionPerformed(..)
* method is performed.
* So we need to handle all the stuff a TAB does.
* ie. if a TAB hits the end of the row, we need to increment
* it to the next Row (if the validation is successful)
* in the current row etc..
* @return JTable
* @see validateBeforeTabbingToNextCell
* @see validateBeforeShiftTabbingToNextCell
* @see validateBeforeMovingToNextCell
* @see validateBeforeMovingDownToCell
* @see validateBeforeMovingUpToCell
* @see validateBeforeMovingLeftToCell
private JTable createTable() {
JTable table = new JTable(createModel()){
private int previousRow =0;
private int previousCol =0;
* Processes mouse events occurring on this component by
* dispatching them to any registered
* <code>MouseListener</code> objects.
* <p>
* This method is not called unless mouse events are
* enabled for this component. Mouse events are enabled
* when one of the following occurs:
* <p><ul>
* <li>A <code>MouseListener</code> object is registered
* via <code>addMouseListener</code>.
* </ul>
* <p>Note that if the event parameter is <code>null</code>
* the behavior is unspecified and may result in an
* exception.
* @param e the mouse event
* @see java.awt.event.MouseEvent
* @see java.awt.event.MouseListener
* @see #addMouseListener
* @see #enableEvents
* @since JDK1.1
protected void processMouseEvent(MouseEvent e) {
boolean canMoveFocus = true;
int currentRowAndColumn[] = getCurrentRowAndColumn(this); //we pull the current row and column
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
if ( e.getID() == MouseEvent.MOUSE_PRESSED || e.getID() == MouseEvent.MOUSE_CLICKED) {
stopCurrentCellBeingEdited(this); //stop the cellbeing edited to grab its value
final String value = (String)getModel().getValueAt(row,column);
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
JOptionPane.showMessageDialog(null,"Alpha value ="+ value ,"Invalid entry!",JOptionPane.WARNING_MESSAGE);
changeSelection(previousRow,previousCol, true, true);
editCellAt(previousRow, previousCol);
requestFocus(); // or t.getEditorCompo
if ( canMoveFocus ) {
super.processMouseEvent(e);
* The method setValueAt of the JTable is overridden
* to save the previousRow/previousCol to enable us to
* get back to the error cell when a Mouse is clicked.
* This is circumvent the problem, when a mouse is clicked in
* a different cell, the control goes to that cell and
* when you ask for getEditingRow , it returns the row that
* the current mouse click occurred. But we need a way
* to stop at the previous cell(ie. the cell that we were editing
* before the mouse click occurred) when an invalid data has
* been entered and return the focus to that cell
* @param aValue
* @param row
* @param col
public void setValueAt(Object aValue,int row, int col) {     
this.previousRow = row;
this.previousCol = col;
super.setValueAt(aValue,row,col);
/* These are the various KeyStrokes like
ENTER,SHIFT-TAB,TAB,Arrow Keys,Numeric Arrow keys being assigned an Abstract action (key string ) in to the
inputMap first . Then an Action is assigned in the ActionMap object
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_TAB,0) ,"validateBeforeTabbingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_TAB,1) ,"validateBeforeShiftTabbingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT,0) ,"validateBeforeMovingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_RIGHT,0) ,"validateBeforeMovingToNextCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN,0) ,"validateBeforeMovingDownToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_DOWN,0) ,"validateBeforeMovingDownToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER,0) ,"validateBeforeMovingDownToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_UP,0) ,"validateBeforeMovingUpToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_UP,0) ,"validateBeforeMovingUpToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT,0) ,"validateBeforeMovingLeftToCell");
table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.getKeyStroke(KeyEvent.VK_KP_LEFT,0) ,"validateBeforeMovingLeftToCell");
table.getActionMap().put("validateBeforeTabbingToNextCell",
new validateBeforeTabbingToNextCell());
table.getActionMap().put("validateBeforeShiftTabbingToNextCell",
new validateBeforeShiftTabbingToNextCell());
table.getActionMap().put("validateBeforeMovingToNextCell",
new validateBeforeMovingToNextCell());
table.getActionMap().put("validateBeforeMovingDownToCell",
new validateBeforeMovingDownToCell());
table.getActionMap().put("validateBeforeMovingUpToCell",
new validateBeforeMovingUpToCell());
table.getActionMap().put("validateBeforeMovingLeftToCell",
new validateBeforeMovingLeftToCell());
table.setPreferredScrollableViewportSize(table.getPreferredSize());
return table;
* A table model is created here for 5 rows/5 columns.
* And the isCellEditable is overridden to return true,
* indicating that the cell can be edited.
* So fine tuned control can be done here by saying,
* the user can be allowed to edit Row 1,3 or 5 only.
* or column 1 only etc..
* @return DefaultTableModel
private DefaultTableModel createModel() {
DefaultTableModel model = new DefaultTableModel(5, 5) {
public boolean isCellEditable(int row, int column) {
return true;
return model;
* This method basically returns the currentRow/currentCol value
* If the current Row/Col is being edited then
* it returns the getEditingRow/getEditingColumn
* If its not being edited,
* it return the getAnchorSelectionIndex of the JTables
* ListSelectionModel.
* If the column or row is -1, then it return 0.
* The first element in the int[] array is the row
* The second element in the int[] array is the column
* @param t input a JTable
* @return int[]
* @see ListSelectionModel
* @see JTable
private int[] getCurrentRowAndColumn(JTable t){
int[] currentRowAndColum = new int[2];
int row, column;
if (t.isEditing()) {
row = t.getEditingRow();
column = t.getEditingColumn();
} else {
row = t.getSelectionModel().getAnchorSelectionIndex();
if (row == -1) {
if (t.getRowCount() == 0) {
//actually this should never happen.. we need to return an exception
return null;
column =t.getColumnModel().getSelectionModel().getAnchorSelectionIndex();
if (column == -1) {
if (t.getColumnCount() == 0) {
//actually this should never happen.. we need to return an exception
return null;
column = 0;
currentRowAndColum[0]=row;
currentRowAndColum[1]=column;
return currentRowAndColum;
* Tbis basically a wrapper method for CellEditors,
* stopCellEditing method.
* We need to do this because,
* for instance we have entered a value in Cell[0,0] as 3
* and when we press TAB or mouse click or any other relevant
* navigation keys,
* ** IF the cell is BEING EDITED,
* when we do a getValueAt(cellrow,cellcol) at the TableModel
* level , it would return "null". To overcome this problem,
* we tell the cellEditor to stop what its doing. and then
* when you do a getValueAt[cellrow,cellcol] it would
* return us the current cells value
* @param t Input a JTable
* @see CellEditor
private void stopCurrentCellBeingEdited(JTable t){
CellEditor ce = t.getCellEditor(); /*this not the ideal way to do..
since there is no way the CellEditor could be null.
But a nullpointer arises when trying to work with mouse.. rather than just
keyboard" */
if (ce!=null) {
ce.stopCellEditing();
* The following Action class handles when a
* RIGHT ARROW or NUMERIC RIGHT ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move it to the
* next Cell.. else take it back to the currentCell
class validateBeforeMovingToNextCell extends AbstractAction {
* The following Action class handles when a
* DOWN ARROW or NUMERIC DOWN ARROW is pressed.
* There is just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move it to
* down by one Cell.. else take it back to the currentCell
* @param e
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column++;
if (column >= t.getColumnCount())
column = column-1;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a
* DOWN ARROW or NUMERIC DOWN ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move it to the
* down by Cell.. else take it back to the currentCell
class validateBeforeMovingDownToCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
row++;
if (row >= t.getRowCount())
row = row - 1;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a
* UP ARROW or NUMERIC UP ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeMovingUpToCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
row--;
if (row <0)
row = 0;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a
* LEFT ARROW or NUMERIC LEFT ARROW is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeMovingLeftToCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column--;
if (column <0)
column = 0;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a TAB is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeTabbingToNextCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column++;
int rows = t.getRowCount(), columns = t.getColumnCount();
while (row < rows) {
while (column < columns) {
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
column++;
row++;
column = 0;
row = 0;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
* The following Action class handles when a SHIFT TAB is pressed.
* There just a basic checking for Numeric values
* (Integer.parseInt) inside the code.
* When validation is successfull, we need to move the cursor/
* editable status up by a Cell.. else take it back to the currentCell
class validateBeforeShiftTabbingToNextCell extends AbstractAction {
public void actionPerformed(ActionEvent e) {
JTable t = (JTable) e.getSource();
int currentRowAndColumn[] = getCurrentRowAndColumn(t);
int row = currentRowAndColumn[0];
int column = currentRowAndColumn[1];
stopCurrentCellBeingEdited(t);
String value = (String)t.getModel().getValueAt(row,column);
if (value!= null && !value.equals("")) {
try {
Integer.parseInt(value);
} catch (NumberFormatException nfe) {
JOptionPane.showMessageDialog(null,"Please input numeric values at cell[row="+row+","+"col="+column+"]","Invalid Input!!",JOptionPane.WARNING_MESSAGE);
t.changeSelection(row, column, true, true);
t.editCellAt(row,column);
t.getEditorComponent().requestFocus();
return;
column--;
int rows = t.getRowCount(), columns = t.getColumnCount();
while ((row < rows) && (row >= 0)) {
while ((column < columns) && (column >= 0)) {
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
column--;
row--;
column = columns - 1;
row = rows - 1;
if (t.isCellEditable(row, column)) {
t.changeSelection(row, column, true, true);
t.editCellAt(row, column);
if ((t.getEditingRow() == row)
&& (t.getEditingColumn() == column)) {
t.requestFocus();
return;
public static void main(String[] args) {
new TableCellValidator();