Horizontal scroll bar doesn't show up?

   JScrollBar _hor开发者_运维问答izontalScroll;
  _verticalScroll = new JScrollBar(JScrollBar.VERTICAL);
   this.add(_verticalScroll);
   _verticalScroll.addAdjustmentListener(this);
   _verticalScroll.setVisible(true);
   _horizontalScroll = new JScrollBar(JScrollBar.HORIZONTAL);
   _horizontalScroll.addAdjustmentListener(this);
   _horizontalScroll.setVisible(true);

I have a code shown above, here vertical scroll bar is working fine, but horizontal scroll bar is not working (doesn't appear on my Swing GUI).

You never add your horizontal scrollbar.

Try adding the entire panel into the JScrollPane.

JScrollPane scrollPane = new JScrollPane(panel,
                     ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, 
                     ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);

And you can add your listeners using

scrollPane.getHorizontalScrollBar().addAdjustmentListener(this);