Resize JTable columns by double-clicking header

Question

I want to implement column resizing in a JTable so that when the user double clicks on the column header with the mouse in the "resize zone" the column automatically adjusts to the width of the longest text in the column. this is how many applications behave (e.g. windows explorer) but I don't think I've ever seen a swing app that does this. I've looked in the API docs for JTable and JTableHeader and I can't see any way of finding out if the mouse is over the edge of a column header. does anyone know of a way to do this?

Answer 1

Is this laf independant?import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
public class Test extends JFrame {
  public Test() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container content = getContentPane();
    String[] head = {"One","Two","Three"};
    String[][] data = {{"R1-C1","R1-C2","R1-C3"},
            {"R2-C1","R2-C2","R2-C3"},
            {"R3-C1","R3-C2","R3-C3"}};
    JTable jt = new JTable(data, head);
    JScrollPane jsp = new JScrollPane(jt);
    content.add(jsp, BorderLayout.CENTER);
    JTableHeader jth = jt.getTableHeader();
    jth.addMouseListener(new MouseAdapter() {
      public void mouseClicked(MouseEvent me) {
        JTableHeader jth = (JTableHeader)me.getSource();
        int col = jth.columnAtPoint(me.getPoint());
        Rectangle r = jth.getHeaderRect(col);
        if (jth.getCursor().equals(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR))) {
          System.out.println("Cursor, col="+col);
    setSize(300, 300);
    setVisible(true);
  public static void main(String args[]) { new Test(); }
}