注意：我已经在整个网络（本网站和其他网站）上进行了搜索，但我自己无法回答。
好，朋友们。我是一名新的 Java 程序员，我们刚刚完成了对选项卡式窗格的介绍。这是我上交作业的状态：它不起作用，我不知道为什么。我已经改变了很多垃圾，我不能再把它放在脑海里了，但我知道这可能是一件非常简单的事情。
对于代码的长度，我深表歉意，但我试图给你我的全部代码，这样你就可以告诉我我把它放在哪里了。
提前致谢。-- 另外，我知道还有其他警告（即未使用的导入），但我并不担心这些。而且，这不会影响我的成绩（正如我所说，已经提交），但我想知道我做错了！
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.text.DecimalFormat;
import java.awt.Color;
import javax.swing.JOptionPane;
import javax.swing.JTabbedPane;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JPanel;
import javax.swing.JComponent;
public class TabbedPane1 extends JPanel
{
public TabbedPane1()
{
JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.addTab("DayGui", new DayGui());
tabbedPane.addTab("OfficeCalc", new OfficeAreaCalculator());
add(tabbedPane);
}
public static void main(String[] args)
{
JFrame myFrame = new JFrame("Tabbed Programs");
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myFrame.add(new TabbedPane1(), BorderLayout.CENTER);
myFrame.pack();
myFrame.setVisible(true);
}
class DayGui extends JPanel
{
private JPanel mainFrame;
private JButton cmdGood;
private JButton cmdBad;
public DayGui()
{
mainFrame = new JPanel();
cmdGood = new JButton("Good");
cmdBad = new JButton("Bad");
Container myContainer = mainFrame;
myContainer.setLayout(new FlowLayout());
myContainer.add(cmdGood);
myContainer.add(cmdBad);
cmdGood.setMnemonic('G');
cmdBad.setMnemonic('B');
mainFrame.setSize(300, 100);
myContainer.setBackground(Color.blue);
cmdGood.setBackground(Color.cyan);
cmdBad.setBackground(Color.cyan);
/*mainFrame.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});*/
ButtonsHandler bhandler = new ButtonsHandler();
cmdGood.addActionListener(bhandler);
cmdBad.addActionListener(bhandler);
//mainFrame.setVisible(true);
}
class ButtonsHandler implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == cmdGood)
JOptionPane.showMessageDialog(null, "Today is a good day!",
"Event Handler Message",
JOptionPane.INFORMATION_MESSAGE);
if(e.getSource() == cmdBad)
JOptionPane.showMessageDialog(null, "Today is a bad day!",
"Event Handler Message",
JOptionPane.INFORMATION_MESSAGE);
}
}
}
class OfficeAreaCalculator extends JPanel
{
private JPanel mainFrame;
private JButton calculateButton;
private JButton exitButton;
private JTextField lengthField;
private JTextField widthField;
private JTextField areaField;
private JLabel lengthLabel;
private JLabel widthLabel;
private JLabel areaLabel;
public OfficeAreaCalculator()
{
mainFrame = new JPanel();
exitButton = new JButton("Exit");
calculateButton = new JButton("Calculate");
lengthField = new JTextField(5);
widthField = new JTextField(5);
lengthLabel = new JLabel("Enter the length of the office:");
widthLabel = new JLabel("Enter the width of the office:");
areaLabel = new JLabel("Office area:");
areaField = new JTextField(5);
areaField.setEditable(false);
Container c = mainFrame;
c.setLayout(new FlowLayout());
c.setBackground(Color.green);
c.add(lengthLabel);
c.add(lengthField);
c.add(widthLabel);
c.add(widthField);
c.add(areaLabel);
c.add(areaField);
c.add(calculateButton);
c.add(exitButton);
calculateButton.setMnemonic('C');
exitButton.setMnemonic('x');
mainFrame.setSize(260, 150);
/*mainFrame.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});*/
CalculateButtonHandler chandler = new CalculateButtonHandler();
calculateButton.addActionListener(chandler);
ExitButtonHandler ehandler = new ExitButtonHandler();
exitButton.addActionListener(ehandler);
FocusHandler fhandler = new FocusHandler();
lengthField.addFocusListener(fhandler);
widthField.addFocusListener(fhandler);
areaField.addFocusListener(fhandler);
//mainFrame.setVisible(true);
}
class CalculateButtonHandler implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
DecimalFormat num = new DecimalFormat(",###.##");
double width, length, area;
String instring;
instring = lengthField.getText();
if(instring.equals(""))
{
instring = ("0");
lengthField.setText("0");
}
length = Double.parseDouble(instring);
instring = widthField.getText();
if(instring.equals(""))
{
instring = ("0");
widthField.setText("0");
}
width = Double.parseDouble(instring);
area = length * width;
areaField.setText(num.format(area));
}
}
class ExitButtonHandler implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
}
class FocusHandler implements FocusListener
{
public void focusGained(FocusEvent e)
{
if(e.getSource() == lengthField || e.getSource() == widthField)
{
areaField.setText("");
}
else if(e.getSource() == areaField)
{
calculateButton.requestFocus();
}
}
public void focusLost(FocusEvent e)
{
if(e.getSource() == widthField)
{
calculateButton.requestFocus();
}
}
}
}
}