Setting Column Header Tool Tips in a JTable Components
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.
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);
public 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) {
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;
}
}
}
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