confuse ouput when clicking a header

[jhon max]

   
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.*;
import javax.swing.table.TableModel;
import javax.swing.table.JTableHeader;

@SuppressWarnings("serial")
public class InventoryTEST3 extends JFrame {

  private JTable table;
  private JPanel lowerPanel;

  private JScrollPane scroll;
  private JSplitPane split;
  private JButton btn;
  private JTableHeader header;

  public InventoryTEST3() {

    initializeInventory();
  }


  private void initializeInventory() {

      btn = new JButton();
      
      lowerPanel = new JPanel();


      lowerPanel.setLayout(null);

      final String[] columnNames = {"First", "Second", "Third", "Fourth"};

      final Object[][] data = new Object[100][columnNames.length];

      table = new JTable(data, columnNames);
      table.setOpaque(false);
      table.setColumnSelectionAllowed(true);
      table.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
      header = table.getTableHeader();
      header.addMouseListener(new MouseListener() {

          int col = table.getSelectedColumn();
            public void mouseClicked(MouseEvent e) {

                System.out.println(col);
            }

            public void mousePressed(MouseEvent e) {
                //
            }

            public void mouseReleased(MouseEvent e) {
                //
            }

            public void mouseEntered(MouseEvent e) {
                //
            }

            public void mouseExited(MouseEvent e) {
               //
            }
          
      });
      
      scroll = new JScrollPane(table);
      scroll.setBounds(0, 0, 1395, 400);

      btn.setBounds(150, 150, 250, 100);

      lowerPanel.add(scroll);

      getContentPane().add(lowerPanel);

      setDefaultCloseOperation(EXIT_ON_CLOSE);
      setTitle("Inventory Window");
      setSize(1400, 800);
      setLocationRelativeTo(null);
      setVisible(true);
  }

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        new InventoryTEST3();
      }
    });
  }

} 

Im having some problem regarding with displaying the selected column header, Im getting -1, how am i supposed to resolve this.. thanks!

[pete stein]

Your current code sets the selected column index before any mouse click has been performed:

    header.addMouseListener(new MouseListener() {

      int col = table.getSelectedColumn();

      public void mouseClicked(MouseEvent e) {

        System.out.println(col);
      }

So it shouldn't be surprising that the only output here is -1. But further, when you click on a column header, afaik, you don't select a column, so even if the getSelectedColumn() call were placed inside of the mouseClicked method, it still won't work. Perhaps what might work better is to call JTableHeader's columnAtPoint method like so:

    header.addMouseListener(new MouseAdapter() {
      
      public void mousePressed(MouseEvent e) {
        int col = header.columnAtPoint(e.getPoint());
        System.out.println(col);
      }
    });

Also, I personally usually prefer to act on mousePressed and not mouseClicked.

[jhon max]

thank you.!

[pete stein]

jhon max wrote:thank you.!

You're welcome and also a caveat: I'm about 90% sure of my answer, but since I'm not a pro, keep an eye on this thread. Usually if the pros see something amiss in my rec, they'll correct it.

Good luck!