Thread: Highlighting both row and column in JTable

I am writing an applet which contains a JTable. The JTable displays Z-Scores for a Statistics application. Because it can be hard to determine the row and column of the highlighted cell, I want to highlight each when the user selects a given cell. I know I can use JTable.setColumnSelectionAllowed(true) to accomplish column highlighting. However if I do the same for the rows, using JTable.setRowSelectionAllowed(true), then I get no highlighting and only the single selected cell ends up with a border. Is there a way to use both?

Take a look at the prepareRenderer method in JTable. I'd suggest extending the JTable and overriding this method, customizing the returned component based upon the JTable selection. Then add a ListSelectionListener and repaint the table upon selection:

	private JTable table = new JTable(){
		@Override public Component prepareRenderer(TableCellRenderer renderer,
                int row,
                int col){
			Component c = super.prepareRenderer(renderer, row, col);
			int selCol = table.getSelectedColumn();
			int selRow = table.getSelectedRow();
			if ( selCol != -1 && selRow != -1 ){
				if ( row == selRow || col == selCol){
					c.setBackground(Color.BLACK);
				}else{
					c.setBackground(Color.WHITE);
				}				
			}
			return c;
		}
	};
////////
//add a listener
		table.getSelectionModel().addListSelectionListener(new ListSelectionListener(){
			public void valueChanged(ListSelectionEvent e){
				table.repaint();
			}
		});

1. Overriding prepareRenderer can do the job, but I feel the programming idiom here is better represented by overriding isCellSelected.
2. You need to repaint the table when a cell in a different column in the selected row is selected. Thus, you need to add a listener to the table's columnModel's selectionModel also.

import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
 
public class RowColumnSelectedTable {
 
  static final int ROWS = 100;
  static final int COLUMNS = 3;
 
  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
 
      @Override
      public void run() {
        new RowColumnSelectedTable().makeUI();
      }
    });
  }
 
  public void makeUI() {
    Object[][] data = new Object[ROWS][COLUMNS];
    String[] headers = new String[COLUMNS];
    for (int column = 0; column < COLUMNS; column++) {
      headers[column] = "Header " + column;
      for (int row = 0; row < data.length; row++) {
        data[row][column] = "Row " + row + ", Column " + column;
      }
    }
    final JTable table = new JTable(data, headers) {
 
      @Override
      public boolean isCellSelected(int row, int column) {
        return isColumnSelected(column) || isRowSelected(row);
      }
    };
    ListSelectionListener listener = new ListSelectionListener() {
 
      @Override
      public void valueChanged(ListSelectionEvent e) {
        table.repaint();
      }
    };
    table.getSelectionModel().addListSelectionListener(listener);
    table.getColumnModel().getSelectionModel().addListSelectionListener(listener);
 
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 400);
    frame.setLocationRelativeTo(null);
    frame.add(new JScrollPane(table));
    frame.setVisible(true);
  }
}

db

Shorter, and doesn't require listeners. Also, more efficient as only the visibleRect of the table is repainted.

import javax.swing.*;
 
public class RowColumnSelectedTable {
 
  static final int ROWS = 100;
  static final int COLUMNS = 3;
 
  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
 
      @Override
      public void run() {
        new RowColumnSelectedTable().makeUI();
      }
    });
  }
 
  public void makeUI() {
    Object[][] data = new Object[ROWS][COLUMNS];
    String[] headers = new String[COLUMNS];
    for (int column = 0; column < COLUMNS; column++) {
      headers[column] = "Header " + column;
      for (int row = 0; row < data.length; row++) {
        data[row][column] = "Row " + row + ", Column " + column;
      }
    }
    final JTable table = new JTable(data, headers) {
 
      @Override
      public boolean isCellSelected(int row, int column) {
        return isColumnSelected(column) || isRowSelected(row);
      }
 
      @Override
      public void changeSelection(int rowIndex, int columnIndex, boolean toggle, boolean extend) {
        super.changeSelection(rowIndex, columnIndex, false, false);
        repaint(getVisibleRect());
      }
    };
 
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 400);
    frame.setLocationRelativeTo(null);
    frame.add(new JScrollPane(table));
    frame.setVisible(true);
  }
}

db

Thanks for the replies! I will be trying these out soon.