JScrollPane 滚动处理

JScrollPane 获取与设置位置正确：
jScrollPane.getViewport().getViewPosition()

别的都不对，

JScrollPane 监听

   JScrollBar bar = srrollPane.getVerticalScrollBar();// 返回控制视口垂直视图位置的垂直滚动条        bar.getPreferredSize();        bar.addAdjustmentListener(new AdjustmentListener() {            @Override            public void adjustmentValueChanged(AdjustmentEvent e) {//                srrollPane= (JScrollPane) evt.getSource();                Point p = srrollPane.getViewport().getViewPosition();                System.out.println("position2:"+p.getY());            }        });// 监听滚动条模型发生更改

srrollPane.getViewport().getHeight()

当var设置为Never时，

jScrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER);

屏幕可见高度：

vbar.getVisibleAmount()

srrollPane.getHeight()，这个不太准确

可以滚动高度为：totalHeight，滚动条子控件的总高度-屏幕可见高度，就是可以滚动总高度

下面是滚动设置方法：

JScrollBar vbar = jScrollPane.getVerticalScrollBar();// 返回控制视口垂直视图位置的垂直滚动条String aa = jScrollPane.getHeight() + " " + vbar.getVisibleAmount() + " " + jScrollPane.getVisibleRect().getHeight() + " ";double totalHeight = backgroundPanel.getPreferredSize().getHeight() - vbar.getVisibleAmount();//-vbar.getHeight()-jScrollPane.getVerticalScrollBarPolicy()*0.5;ylocation = ylocation * totalHeight;if (ylocation < totalHeight) {    Point target = jScrollPane.getViewport().getLocation();    target.setLocation(target.getX(), ylocation);    jScrollPane.getViewport().setViewPosition(target);}