我正在编写一个登录GUI,并且想单击取消按钮关闭整个程序。我是一名新生计算机科学专业,并且对Java和编程一般来说还是半新的。这里是我的代码:单击JButton时退出JFrame
主类:
public class loginGui
{
public static void main(String[] args)
{
lGui gui = new lGui();
lGui.gui();
}
}
GUI类:
public class lGui
{
public static void gui()
{
JFrame frame;
JTextField field;
JLabel l;
JPasswordField p;
JButton login, cancel;
JCheckBox check;
frame = new JFrame("Login");
frame.setSize(300, 150);
frame.getContentPane().setBackground(Color.LIGHT_GRAY);
frame.setLocation(300, 200);
frame.setLayout(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
l = new JLabel("Username: ");
l.setLocation(15, 14);
l.setSize(l.getPreferredSize());
frame.add(l);
field = new JTextField("Username");
field.setColumns(15);
field.setSize(field.getPreferredSize());
field.setBackground(Color.DARK_GRAY);
field.setForeground(Color.LIGHT_GRAY);
field.setLocation(90, 10);
field.setToolTipText("Enter User Name");
frame.add(field);
l = new JLabel("Password: ");
l.setLocation(15, 54);
l.setSize(l.getPreferredSize());
frame.add(l);
p = new JPasswordField("Password");
p.setColumns(15);
p.setSize(p.getPreferredSize());
p.setBackground(Color.DARK_GRAY);
p.setForeground(Color.LIGHT_GRAY);
p.setLocation(90, 50);
p.setToolTipText("Enter Password");
frame.add(p);
login = new JButton("Login");
login.setSize(login.getPreferredSize());
login.setLocation(195, 78);
login.setToolTipText("Login");
frame.add(login);
login.addActionListener(new loginAction());
cancel = new JButton("Cancel");
cancel.setSize(cancel.getPreferredSize());
cancel.setLocation(95, 78);
cancel.setToolTipText("Cancel");
frame.add(cancel);
cancel.addActionListener(new cancelAction());
check = new JCheckBox("Remember me?");
check.setSize(check.getPreferredSize());
check.setLocation(120, 100);
check.setToolTipText("Remember your username for next time");
frame.add(check);
frame.setVisible(true);
}
static class cancelAction implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
frame.dispose();
}
}
static class loginAction implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
}
}
}
我守在取消按钮的ActionListener在这里得到一个 “无法找到符号” 错误:
frame.dispose();