Question

I followed some tips in this guide: JTable with horizontal scrollbar but still having problems.

I have two column headers: Name and Description (for our purposes in this ex.)

I want to be able to scroll horizontally whenever an entry is added (ie: Name/Description is just 1 line). However, Swing doesn’t seem to default to that behavior!

I have a JTable embedded in a ScrollPane. JScrollPane has the following parameters: JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED and JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED

If I disable with: myTable.AutoResizeMode(AUTO_RESIZE_OFF) the column headers don’t fill up the whole table (maybe just 1/2 of the table). I have to manually resize the “Description” Column to see the whole thing.

How can I have autoresizing, but the horizontal scrolling still works?

Answer 1

You can extend JTable as follows:

public class JHorizontalFriendlyTable extends JTable {

  @Override
  public Dimension getPreferredSize() {
    if (getParent () instanceof JViewport) {
      if (
        ((JViewport) getParent()).getWidth() > super.getPreferredSize().width)
      ) {
        return getMinimumSize();
      }
    }
    return super.getPreferredSize(); 
  }

  @Override
  public boolean getScrollableTracksViewportWidth () {
    if (autoResizeMode != AUTO_RESIZE_OFF) {
      if (getParent() instanceof JViewport) {
        return (((JViewport) getParent()).getWidth() > getPreferredSize().width);
      }
      return true;
    }
    return false;
  }
}

sample usage:

jScrollPane1 = new JScrollPane();
TableModel jTable1Model = new DefaultTableModel(...); 
JTable jTable1 = new JHorizontalFriendlyTable();
jScrollPane1.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
jScrollPane1.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
jScrollPane1.setViewPortView(jTable1);
jTable1.setModel(jTable1Model);
jTable1.setPreferredSize(new java.awt.Dimension(1051,518));
jTable1.setPreferredScrollableViewPortSize(new java.awt.Dimension(1000,528));
jTable1.getSize(new java.awt.Dimension(1051, 528));

if (jTable1.getPreferredScrollableViewPortSize().getWidth() > 
  ((JViewPort) jTable1.getParent()).getPreferredSize().getWidth())
  {
  jTable1.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
  jTable1.doLayout();
}

jTable1.setDragEnabled(false);
jTable1.setColumnSelectionAllowed(false);
jTable1.getTableHeader().setReorderingAllowed(false);