loginwindow.java

这是一个登陆框代码

import java.awt.*;
import javax.swing.*;
import java.util.*;
import java.awt.event.*;
class LoginWindow extends JDialog implements  ActionListener{
	JPanel p1 = new JPanel();
	JPanel p2 = new JPanel();
	JPanel p3 = new JPanel();
	JPanel p4 = new JPanel();
	JPanel p5 = new JPanel();
	JTextField txtUserName=new JTextField(15);
	JPasswordField txtPassword=new JPasswordField(15);
	JButton ok=new JButton("确定");
	JButton cancel=new JButton("取消");
	public LoginWindow(){
		setModal(true);
		setBackground(Color.LIGHT_GRAY);
		Container contentPane=this.getContentPane();
		contentPane.setLayout(new GridLayout(5,1));
		p2.add(new JLabel("用户名"));p2.add(txtUserName);
		p3.add(new JLabel("密码"));p3.add(txtPassword);
		p4.add(ok);p4.add(cancel);
		ok.addActionListener(this);
		cancel.addActionListener(this);
		contentPane.add(p1);
		contentPane.add(p2);
		contentPane.add(p3);
		contentPane.add(p4);
		contentPane.add(p5);
		setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
		setSize(300,400);
		Dimension screen=Toolkit.getDefaultToolkit().getScreenSize();
		setLocation((screen.width-300)/2,(screen.height-220)/2);
		setTitle("登录窗口");
	//setReSizable(false);
		setVisible(true);
		
	}
	public void actionPerformed(ActionEvent e){
		if(e.getSource()==ok||e.getSource()==txtPassword){
			if(txtUserName.getText().trim().equals("yang")&&txtPassword.getText().trim().equals("1234")){
				dispose();
				//new MainWindow();
				
			}
		else{
			JOptionPane.showMessageDialog(null,"用户名或密码错误");
			txtUserName.requestFocus();
			txtUserName.setSelectionStart(0);
			txtUserName.setSelectionEnd(txtUserName.getText().length());
			
		}
		
		
		
		
		}
	else if(e.getSource()==cancel){
		dispose();
		System.exit(0);
		
	}
	else if(e.getSource()==txtUserName)
	txtPassword.requestFocus();
	
	
	
	
	
	
	}
	
	
	public static void main(String args[])
	{JDialog.setDefaultLookAndFeelDecorated(true);
	Font font = new Font("JFrame",Font.PLAIN,14);
	Enumeration keys = UIManager.getLookAndFeelDefaults().keys();
	while(keys.hasMoreElements()){
		Object key = keys.nextElement();
		if(UIManager.get(key)instanceof Font)UIManager.put(key,font);
		
	}
	new LoginWindow();
	}
}