[JAVA] Impostare tooltip in header di una JTable

[abcd1000]

Volevo mostraere un tooltip quando viene passato il mouse sopra il nome delle colonne di una jtable
Ho provato questo codice, ma non funziona
Sapete dirmi dov'e' l'errore?

package jtable;

import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.util.HashMap;
import java.util.Map;

import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;

//To display a tool tip for a column header, install a mouse motion listener on the header component and change its tool tip based on which column header is under the cursor. 
public class ToolTipForCell {

	public ToolTipForCell() {
		//super();
		int rows = 10;
	    int cols = 5;
	    JTable table = new JTable(rows, cols);
	    
	    JTableHeader header = table.getTableHeader();
	    
	    ColumnHeaderToolTips tips = new ColumnHeaderToolTips();
	    
	    // Assign a tooltip for each of the columns
	    for (int c=0; c<table.getColumnCount(); c++) {
	        TableColumn col = table.getColumnModel().getColumn(c);
	        tips.setToolTip(col, "Col "+c);
	    }
	    header.addMouseMotionListener(tips);
	    
	    JFrame frame = new JFrame();
	    frame.getContentPane().add(table);
	    frame.pack();
	    frame.setLocationRelativeTo(null);
	    frame.setVisible(true);
	}
	    

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		new ToolTipForCell();
	}

	class ColumnHeaderToolTips extends MouseMotionAdapter {
        // Current column whose tooltip is being displayed.
        // This variable is used to minimize the calls to setToolTipText().
        TableColumn curCol;
    
        // Maps TableColumn objects to tooltips
        Map tips = new HashMap();
    
        // If tooltip is null, removes any tooltip text.
        public void setToolTip(TableColumn col, String tooltip) {
            if (tooltip == null) {
                tips.remove(col);
            } else {
                tips.put(col, tooltip);
            }
        }
    
        public void mouseMoved(MouseEvent evt) {
        	System.out.println("mouse moved!");
            TableColumn col = null;
            JTableHeader header = (JTableHeader)evt.getSource();
            JTable table = header.getTable();
            TableColumnModel colModel = table.getColumnModel();
            int vColIndex = colModel.getColumnIndexAtX(evt.getX());
    
            // Return if not clicked on any column header
            if (vColIndex >= 0) {
                col = colModel.getColumn(vColIndex);
            }
    
            if (col != curCol) {
                header.setToolTipText((String)tips.get(col));
                curCol = col;
            }
        }
    }

}

[abcd1000]

qualche idea?

[abcd1000]

Risolto

package jtable;

import java.awt.BorderLayout;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumnModel;

/**
 * @version 1.0 02/25/99
 */
public class ToolTipHeaderTable extends JPanel {

	private static final long serialVersionUID = 1L;

	public ToolTipHeaderTable() {
		setLayout(new BorderLayout());
		String[] headerStr = { "default", "jw", "ja", "la", "unknown" };
		String[] toolTipStr = { "", "Javanese", "Japanese", "Latin" };

		DefaultTableModel dm = new DefaultTableModel(headerStr, 4);
		JTable table = new JTable(dm);

		ToolTipHeader header = new ToolTipHeader(table.getColumnModel());
		header.setToolTipStrings(toolTipStr);
		header.setToolTipText("Default ToolTip TEXT");
		table.setTableHeader(header);

		JScrollPane pane = new JScrollPane(table);
		add(pane, BorderLayout.CENTER);
	}

	public static void main(String[] args) {
		JFrame f = new JFrame("ToolTipHeaderTable Example");
		f.getContentPane().add(new ToolTipHeaderTable(), BorderLayout.CENTER);
		f.setSize(400, 100);
		f.setVisible(true);
		f.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
	}

	class ToolTipHeader extends JTableHeader {

		private static final long serialVersionUID = 1L;

		String[] toolTips;

		public ToolTipHeader(TableColumnModel model) {
			super(model);
		}

		public String getToolTipText(MouseEvent e) {
			int col = columnAtPoint(e.getPoint());
			int modelCol = getTable().convertColumnIndexToModel(col);
			String retStr;
			try {
				retStr = toolTips[modelCol];
			} catch (NullPointerException ex) {
				retStr = "";
			} catch (ArrayIndexOutOfBoundsException ex) {
				retStr = "";
			}
			if (retStr.length() < 1) {
				retStr = super.getToolTipText(e);
			}
			return retStr;
		}

		public void setToolTipStrings(String[] toolTips) {
			this.toolTips = toolTips;
		}
	}
}