Scroll to last added row in JTable

Question

I use a HashMap to fill a JTable, which is more or less continuously updated:

public Map< Long, MyObject > tableData = new HashMap< Long, MyObject >();

Every time a new element is added to the map the table model is notified:

tableData.put(id, anObject);

AbstractTableModel atm = (AbstractTableModel)model;
atm.fireTableDataChanged();

In Addition I have a TableRowSorter which sorts the rows according to a specific criteria:

TableRowSorter<TableModel> sorter = new TableRowSorter<TableModel>(model);
.
.
.
table.setRowSorter(sorter);

My goal is that the (vertical) scrollbar always jumps to the last added row, which can be somwhere in the mid of the table because of the sorter probably using this:

table.scrollRectToVisible(table.getCellRect(row,0, true));

The problem is I do not know the index of the row :) Where can I hook in to get this index?

unrelated: a) never-ever fire a event on behalf of the model, instead implement a custom model with with modifying api that fulfills its notification contract itself b) always fire the most narrow event that's possible, f.i. an update/insert (vs. the shotgun dataChanged) c) if your rowSorter is just the plain core version, consider using table.setAutoCreateRowSorter(true) instead of creating and setting it manually — kleopatra

kleopatra kleopatra · Accepted Answer · 2013-06-25T09:16:35

Scrolling to a newly inserted row in a potentially sorted table involves

listening to changes in the table model
converting the rowIndex of the event (it is in model coordiates) to view coordinates
scrolling to the view position

In code:

final JTable table = new JTable();
TableModelListener l = new TableModelListener() {

    @Override
    public void tableChanged(TableModelEvent e) {
        if (TableUtilities.isInsert(e)) {
            SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    int viewRow = table.convertRowIndexToView(e.getFirstRow());
                    table.scrollRectToVisible(table.getCellRect(viewRow, 0, true));    
                }
            });
        }
    }
};
table.getModel().addTableModelListener(l);

Two important aspects:

your model implemenation must fire the correct event, that is a insert, not a dataChanged
invoking both index conversion and scrolling guarantees that the table (which is listening to the model as well) has updated all internal state according to the model change.

Scroll to last added row in JTable

1 Answers