让程序运行,出来的总是一个框,里面没有任何东西,只有人为的去改变它的大小,他才显示,当你再人为的弄到先前的大小,他依旧显示,那怎么才能让他一开始就显示啊?
还有就是能不能帮我看下那个JScrollPane,当我改变大小时,滚动的一个按钮就看不见了,根本无法实现操作,我哪里错了啊??谢谢!
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class Three implements ActionListener
{
JFrame f;
JComboBox jcb;
JTextArea jta;
JPanel p1,p2;
JScrollPane jsp;
public static void main(String args[])
{
Three three= new Three();
three.go();
}
public void go()
{
f=new JFrame("Select Demo");
f.setSize(300,300);
f.setVisible(true);
p1=new JPanel();
p2=new JPanel();
String[] itemList={"Mouse Entered","Mouse Pressed","Mouse Released","Mouse Clicked","Mouse Exited"};
jcb=new JComboBox(itemList);
jcb.setSelectedIndex(2);
jta=new JTextArea(10,10);
jsp=new JScrollPane(jta,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
p1.add(jcb);
p2.add(jsp);
f.getContentPane().add(p1,BorderLayout.WEST);
f.getContentPane().add(p2,BorderLayout.EAST);
jcb.addActionListener(this);
jcb.setEditable(false);
}
public void actionPerformed(ActionEvent e)
{
jta.append("\n");
jta.append((String)jcb.getSelectedItem());
}
}
还有就是能不能帮我看下那个JScrollPane,当我改变大小时,滚动的一个按钮就看不见了,根本无法实现操作,我哪里错了啊??谢谢!
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class Three implements ActionListener
{
JFrame f;
JComboBox jcb;
JTextArea jta;
JPanel p1,p2;
JScrollPane jsp;
public static void main(String args[])
{
Three three= new Three();
three.go();
}
public void go()
{
f=new JFrame("Select Demo");
f.setSize(300,300);
f.setVisible(true);
p1=new JPanel();
p2=new JPanel();
String[] itemList={"Mouse Entered","Mouse Pressed","Mouse Released","Mouse Clicked","Mouse Exited"};
jcb=new JComboBox(itemList);
jcb.setSelectedIndex(2);
jta=new JTextArea(10,10);
jsp=new JScrollPane(jta,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
p1.add(jcb);
p2.add(jsp);
f.getContentPane().add(p1,BorderLayout.WEST);
f.getContentPane().add(p2,BorderLayout.EAST);
jcb.addActionListener(this);
jcb.setEditable(false);
}
public void actionPerformed(ActionEvent e)
{
jta.append("\n");
jta.append((String)jcb.getSelectedItem());
}
}
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f.pack();
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.WindowConstants;
public class Three implements ActionListener
{
JFrame f;
JComboBox jcb;
JTextArea jta;
JPanel p1,p2;
JScrollPane jsp;
public static void main(String args[])
{
Three three= new Three();
three.go();
}
public void go()
{
f=new JFrame("Select Demo");
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.setSize(300,300);
p1=new JPanel();
p2=new JPanel();
String[] itemList={"Mouse Entered","Mouse Pressed","Mouse Released","Mouse Clicked","Mouse Exited"};
jcb=new JComboBox(itemList);
jcb.setSelectedIndex(2);
jta=new JTextArea(10,10);
jsp=new JScrollPane(jta,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
p1.add(jcb);
p2.add(jsp);
f.getContentPane().add(p1,BorderLayout.WEST);
f.getContentPane().add(p2,BorderLayout.EAST);
jcb.addActionListener(this);
jcb.setEditable(false);
f.setVisible(true);
}
public void actionPerformed(ActionEvent e)
{
jta.append("\n");
jta.append((String)jcb.getSelectedItem());
}
}
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
加上这句话,否则关闭窗口后,JVM 不会关闭