我不是一个优秀的java程序员。当我使用这种编码时,我遇到了一些错误。任何人都可以帮助我吗?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JOptionPane;
public class test4 implements ActionListener
{
public static void main(String[] args)throws Exception
{
JFrame f=new JFrame("test 4");
JButton b=new JButton("gud morning");
JButton b1=new JButton("yes or no");
b.addActionListener(this);
b1.addActionListener(this);
Container content=f.getContentPane();
content.add(b,BorderLayout.NORTH);
content.add(b1,BorderLayout.SOUTH);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(100,100);
}
}
public void actionPerformed(ActionEvent e)
{
String s=e.getActionCommand();
if(s.equals("gud morning"))
{
JOptionPane.showMessageDialog(f,"gud morning","My Message");
}
else if(s.equals("yes or no"))
{
if(JOptionPane.showConfirmMessageDialog(f,"yes or no","it is also my message",JOptionPane.YES_NO_CANCEL_OPTION)==0);
{
JOptionPane.showMessageDialog(f,"u clicked yes button");
}
else
{
JOptionPane.showMessageDialog(f,"u clicked no button");
}
}
}
我收到此错误:
\ram>javac test4.java test4.java:22: error: class, interface, or enum expected public void actionPerformed(ActionEvent e) ^ test4.java:25: error: class, interface, or enum expected if(s.equals("gud morning")) ^ test4.java:28: error: class, interface, or enum expected } ^ 3 errors
答案 0 :(得分:2)
if
语句正在被;
发送,这会导致else
分支不正确。删除;
if(JOptionPane.showConfirmMessageDialog(f,"yes or no","it is also my message",JOptionPane.YES_NO_CANCEL_OPTION)==0);
变为:
if(JOptionPane.showConfirmMessageDialog(f,"yes or no","it is also my message",JOptionPane.YES_NO_CANCEL_OPTION)==0)
在}
开始之前,你还有一个额外的大括号actionPerformed
。