Java Swing：JScrollPane无法正常工作(Java Swing: JScrollPane not working)

 我有一个包含一些字段的JPanel。 JPanel的高度是有限的所以我必须在它周围放置一个JScrollPane，以便人们可以向下滚动。 
 
 如下所示，它显示完美。 但你不能向下滚动（或向上）。 
 
DetailPanel detail = new DetailPanel();
JScrollPane jsp = new JScrollPane(detail);
jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
jsp.setBounds(745, 10, 235, 225);
add(jsp);
 
 细节面板： 
 
private void init(){
            setLayout(null);
            setSize(140, 400);
            int x = 5, y = 0;
            for(int i = 0; i < lbls.length; i++) {
                JLabel lbl = new JLabel(lbls[i]);
                lbl.setBounds(x, y, 200, 25);
                add(lbl);
                fields[i] = new JTextField();
                fields[i].setBounds(x, y+26, 200, 25);
                add(fields[i]);
                y+=50;
            }
        }
 

I have a JPanel which contains some fields. The height of the JPanel is limited so I have to put a JScrollPane around it so people can scroll down.
 
As you can see below, it displays perfectly. But you can't scroll down (or up).
 
DetailPanel detail = new DetailPanel();
JScrollPane jsp = new JScrollPane(detail);
jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
jsp.setBounds(745, 10, 235, 225);
add(jsp);
 
Detail panel:
 
private void init(){
            setLayout(null);
            setSize(140, 400);
            int x = 5, y = 0;
            for(int i = 0; i < lbls.length; i++) {
                JLabel lbl = new JLabel(lbls[i]);
                lbl.setBounds(x, y, 200, 25);
                add(lbl);
                fields[i] = new JTextField();
                fields[i].setBounds(x, y+26, 200, 25);
                add(fields[i]);
                y+=50;
            }
        }
 

原文：https://stackoverflow.com/questions/10016879