SimpleTextPaneResizeable.java 文件源码

protected JScrollPane getScrollPane() {

       // Get scrollpane, if first time calling this method then add an addjustment listener
       // to the scroll pane

       if(this.getParent() instanceof JViewport) {
           if(scrollPane == null) {
               JViewport p = (JViewport)this.getParent();
               scrollPane = (JScrollPane)p.getParent();
               scrollPane.getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener(){
                   @Override
                   public void adjustmentValueChanged(AdjustmentEvent e) {
                       //need to repaint the triangle when scroll bar moves
                       repaint();
                   }
               });
           }
       }
       return scrollPane;
   }