Column moved [finished] event in JTable

Question

How should I detect that column moved action is finished in JTable? I've added columnModeListener to my column model but the problem is columnMoved method is called every time a column moves (by certain pixels). I don't want this behavior. I just want to detect when the column dragging is finished.

columnModel.addColumnModelListener(new TableColumnModelListener() {

            public void columnAdded(TableColumnModelEvent e) {
            }

            public void columnRemoved(TableColumnModelEvent e) {
            }

            public void columnMoved(TableColumnModelEvent e) {
                //this is called so many times
                //I don't want this, but something like column moved finished event
                System.out.println("Moved "+e.getFromIndex()+", "+e.getToIndex());
            }

            public void columnMarginChanged(ChangeEvent e) {
            }

            public void columnSelectionChanged(ListSelectionEvent e) {
            }
        });

I hope it is clear what I'm looking for. Thanks.

Answer 1

If I understand you correctly, maybe you want to look at the mouse listeners. Maybe the MOUSE_RELEASED event?

Answer 2

Here's an inner class I use to determine when the column ordering has changed. Note that the user may not have let go of the mouse at this point, so the dragging may continue further.

private class ColumnUpdateListener implements TableColumnModelListener {

   int lastFrom = 0;
   int lastTo = 0;

   private void verifyChange(int from, int to) {
      if (from != lastFrom || to != lastTo) {
         lastFrom = from;
         lastTo = to;

         ///////////////////////////////////////
         // Column order has changed!  Do something here
         ///////////////////////////////////////
      }
   }

   public void columnMoved(TableColumnModelEvent e) {
      verifyChange(e.getFromIndex(), e.getToIndex());
   }

   public void columnAdded(TableColumnModelEvent e) {
      verifyChange(e.getFromIndex(), e.getToIndex());
   }

   public void columnRemoved(TableColumnModelEvent e) {
      verifyChange(e.getFromIndex(), e.getToIndex());
   }

   public void columnMarginChanged(ChangeEvent e) {}
   public void columnSelectionChanged(ListSelectionEvent e) {}

}

It's worked well for me.

Answer 3

This is what I ended up doing. I know it is dirty, but it fits for what I'm looking:

boolean dragComplete = false;
        apTable.getTableHeader().addMouseListener(new MouseAdapter() {
            @Override
            public void mouseReleased(MouseEvent e) {
                if (dragComplete) {
                    System.out.println("Drag completed");
                }
                dragComplete = false;
            }
        });
        columnModel.addColumnModelListener(new TableColumnModelListener() {

            public void columnAdded(TableColumnModelEvent e) {
            }

            public void columnRemoved(TableColumnModelEvent e) {
            }

            public void columnMoved(TableColumnModelEvent e) {
                dragComplete = true;
            }

            public void columnMarginChanged(ChangeEvent e) {
            }

            public void columnSelectionChanged(ListSelectionEvent e) {
            }
        });

Answer 4

This might be a better approach:

table.setTableHeader(new JTableHeader(table.getColumnModel()) {

      @Override
      public void setDraggedColumn(TableColumn column) {
        boolean finished = draggedColumn != null && column == null;
        super.setDraggedColumn(column);
        if (finished) {
          onColumnChange(table); // Handle the event here...
        }
      }
    });