import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.Border;
import javax.swing.plaf.basic.BasicArrowButton;public class ButtonsDemo extends JFrame
{
private JButton jb = new JButton("JButton");
private BasicArrowButton up = new BasicArrowButton(BasicArrowButton.NORTH)
down = new BasicArrowButton(BasicArrowButton.SOUTH);
right = new BasicArrowButton(BasicArrowButton.EAST);
left = new BasicArrowButton(BasicArrowButton.WEST);
public ButtonsDemo(String title)
{
super(title);
Container contentPane = getContentPane();
contentPane.setLayout(new FlowLayout());
contentPane.add(jb);
contentPane.add(new JToggleButton("JToggleButton"));
contentPane.add(new JCheckBox("JCheckBox"));
contentPane.add(new JRadioButton("JRadioButton"));
JPanel jp = new JPanel();
jp.setBorder(new TitledBorder("Directions"));
jp.add(up);
jp.add(down);
jp.add(left);
jp.add(right);
contentPane.add(jp);
pack();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args)
{
new ButtonsDemo("Hello");
}
}报错:Exception in thread "main" java.lang.Error: Unresolved compilation problem: at ButtonsDemo.main(ButtonsDemo.java:38)
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.Border;
import javax.swing.plaf.basic.BasicArrowButton;public class ButtonsDemo extends JFrame
{
private JButton jb = new JButton("JButton");
private BasicArrowButton up = new BasicArrowButton(BasicArrowButton.NORTH)
down = new BasicArrowButton(BasicArrowButton.SOUTH);
right = new BasicArrowButton(BasicArrowButton.EAST);
left = new BasicArrowButton(BasicArrowButton.WEST);
public ButtonsDemo(String title)
{
super(title);
Container contentPane = getContentPane();
contentPane.setLayout(new FlowLayout());
contentPane.add(jb);
contentPane.add(new JToggleButton("JToggleButton"));
contentPane.add(new JCheckBox("JCheckBox"));
contentPane.add(new JRadioButton("JRadioButton"));
JPanel jp = new JPanel();
jp.setBorder(new TitledBorder("Directions"));
jp.add(up);
jp.add(down);
jp.add(left);
jp.add(right);
contentPane.add(jp);
pack();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args)
{
new ButtonsDemo("Hello");
}
}报错:Exception in thread "main" java.lang.Error: Unresolved compilation problem: at ButtonsDemo.main(ButtonsDemo.java:38)
down = new BasicArrowButton(BasicArrowButton.SOUTH);
right = new BasicArrowButton(BasicArrowButton.EAST);
left = new BasicArrowButton(BasicArrowButton.WEST);
三个变量也没有定义。
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.Border;
import javax.swing.border.TitledBorder;
import javax.swing.plaf.basic.BasicArrowButton; public class ButtonDemo extends JFrame
{
private JButton jb = new JButton("JButton");
private BasicArrowButton up = new BasicArrowButton(BasicArrowButton.NORTH),
down = new BasicArrowButton(BasicArrowButton.SOUTH),
right = new BasicArrowButton(BasicArrowButton.EAST),
left = new BasicArrowButton(BasicArrowButton.WEST); public ButtonDemo(String title)
{
super(title);
Container contentPane = getContentPane();
contentPane.setLayout(new FlowLayout());
contentPane.add(jb);
contentPane.add(new JToggleButton("JToggleButton"));
contentPane.add(new JCheckBox("JCheckBox"));
contentPane.add(new JRadioButton("JRadioButton"));
JPanel jp = new JPanel();
jp.setBorder(new TitledBorder("Directions"));
jp.add(up);
jp.add(down);
jp.add(left);
jp.add(right);
contentPane.add(jp); pack();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); }
public static void main(String[] args)
{
new ButtonDemo("Hello");
}
}