JList的滚动条添加问题

robin2722 2007-09-09 01:13:55

我的源文件是这样的：有两个文件：Application1.java和Frame1.java
其中：Application.java如下：
package jlist_test;

import javax.swing.UIManager;
import java.awt.*;

/**
* Title: 
* Description: 
* Copyright: Copyright (c) 2007
* Company: 
* @author not attributable
* @version 1.0
*/

public class Application1 {
boolean packFrame = false;

//Construct the application
public Application1() {
Frame1 frame = new Frame1();
//Validate frames that have preset sizes
//Pack frames that have useful preferred size info, e.g. from their layout
if (packFrame) {
frame.pack();
}
else {
frame.validate();
}
//Center the window
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Dimension frameSize = frame.getSize();
if (frameSize.height > screenSize.height) {
frameSize.height = screenSize.height;
}
if (frameSize.width > screenSize.width) {
frameSize.width = screenSize.width;
}
frame.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2);
frame.setVisible(true);
}
//Main method
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}
catch(Exception e) {
e.printStackTrace();
}
new Application1();
}
}

Frame1.java如下：

package jlist_test;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.borland.jbcl.layout.*;

/**
* Title: 
* Description: 
* Copyright: Copyright (c) 2007
* Company: 
* @author not attributable
* @version 1.0
*/

public class Frame1 extends JFrame {
JPanel contentPane;
XYLayout xYLayout1 = new XYLayout();
//JList jList1 = new JList();
String[] str = {"Math","English","Physics","Chemic","Biology","Politics"};
JList jList1 = new JList(str);
JScrollPane listScrollPane = new JScrollPane(jList1);
//Construct the frame
public Frame1() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
//Component initialization
private void jbInit() throws Exception {
contentPane = (JPanel) this.getContentPane();
contentPane.setLayout(xYLayout1);
this.setSize(new Dimension(400, 300));
this.setTitle("Frame Title");
jList1.setVisibleRowCount(4);
contentPane.add(jList1, new XYConstraints(72, 86, 213, 73));
}
//Overridden so we can exit when window is closed
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if (e.getID() == WindowEvent.WINDOW_CLOSING) {
System.exit(0);
}
}
}

但是在显示出来的列表框中却找不到滚动条的踪影，请问是哪里出了问题，请高手帮忙解决一下，谢谢！用List可以产生滚动条！

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