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).

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You never add your horizontal scrollbar.

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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);