我似乎在代码中发现了一个新问题。我的代码没有(可见的(错误，但我仍然没有得到框架。请帮助
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class hello{
//Int's and things
static JButton Play = new JButton("<PLAY>");
static JFrame pane = new JFrame("CIrCUT 0.0.2");
static JLabel Title = new JLabel("CIrCUT");
static JLabel none = new JLabel(" ");
static JPanel panel = new JPanel(new GridLayout(10,10,10,10));
static JButton Options = new JButton("<OPTIONS>");
static JPanel panel2 = new JPanel(new GridLayout(10,10,10,10));
static String b[] = new String[3];
static int panelLoct =1;
JComboBox optionlist = new JComboBox();
void initialize(){
b[0] = "High";
b[1] = "Medium";
b[2] = "Low";
//title
pane.setTitle("CIrCUT 0.0.2");
//drop down
optionlist .setModel(new DefaultComboBoxModel(new String[] {"Option", "High", "Medium", "Low"}));
optionlist.setSelectedIndex(3);
optionlist.addActionListener((ActionListener) this);
//other pane-related things
if(panelLoct==1){
pane.setLayout(new GridLayout(10,10));
panel.setMaximumSize(new Dimension(500,500));
pane.setSize(500,500);
pane.setMaximumSize(new Dimension(500,500));
panel.add(Title);
panel.add(none);
panel.add(Play);
panel.add(Options);
panel2.add(optionlist);
Play.setSize(new Dimension(500,450));
pane.setLocation(500,50);
pane.setBackground(Color.lightGray);
pane.setContentPane(panel);
pane.pack();
pane.setMinimumSize(new Dimension(500,500));
pane.setContentPane(panel);
OptionButtonHandler cbHandler = new OptionButtonHandler();
Options.addActionListener(cbHandler);
pane.setVisible(true);
}
}
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
private static class OptionButtonHandler implements ActionListener
{
public void actionPerformed(ActionEvent e){
pane.remove(panel);
pane.add(panel2);
}
}
public void actionPerformed(ActionEvent e) {
JComboBox cb = (JComboBox)e.getSource();
cb.getSelectedItem();
}
public static void main(String args[])
{
hello a = new hello();
a.initialize();
}
}
任何帮助都将不胜感激。这是我尝试运行时遇到的错误
Exception in thread "main" java.lang.ClassCastException: hello cannot be cast to java.awt.event.ActionListener
at hello.initialize(hello.java:39)
at hello.main(hello.java:83)
这可能是一个新手错误，但找不到任何解决方法。
您的程序确实有一个明显的错误，正是在它失败的地方：
optionlist.addActionListener((ActionListener) this);
CCD_ 1是对CCD_ 2的实例的引用。hello类没有实现ActionListener，那么您如何期望转换成功呢？
您给出的ActionListener的唯一实现是OptionButtonHandler。也许你的意思是：
optionlist.addActionListener(new OptionButtonHandler());
optionlist.addActionListener((ActionListener) this);
仅仅因为你愿意做某事并不意味着它是可能的。在这种情况下，hello不是ActionListener，因此这将失败。
如果你发现自己在选角，你可能有问题。
您必须实现ActionListener。
public class Hello implements ActionListener{
}