第二次作业

     

package javazuoye;
import javax.swing.*;

import java.awt.*;
import java.awt.event.*;
public class denglujiemian {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        LoginDialog lo = new LoginDialog();
        lo.setVisible(true);
    }

}
public class MainWindow extends JFrame{
    

    JLabel but1;
    MainWindow(){
        
        setTitle("系统登录");
        setBounds(400,200,300,180);
        setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
//        setLayout(null);


        addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                System.exit(0);
            }
        });
        but1 = new JLabel("登录成功！");
        this.add(but1);
    
    }
    
    
}

public class LoginDialog extends JDialog {
    JLabel name;
    JLabel a2;
    JComboBox a3;
    JPasswordField password;
    JButton shi;
    JButton fou;
    
    LoginDialog(){
        method1();
    }

    private void method1() {
        // TODO Auto-generated method stub
        setTitle("登录系统");
        setBounds(500,250,220,140);
        setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);
        setLayout(null);
        setModal(true);
//        this.setResizable(false);
        
        name = new JLabel("用户名:");
        name.setBounds(20,10,50,20);
        this.add(name);
        a2 = new JLabel("密码:");
        a2.setBounds(20,32,50,20);
        this.add(a2);
        
        a3 = new JComboBox();
        a3.addItem("huakaihualuo");
        a3.addItem("hellow");
        a3.setBounds(75,10,105,20);
        this.add(a3);
        password = new JPasswordField("666666");
        password.setBounds(75,33,105,20);
        password.setEchoChar('*');
        this.add(password);
        
        shi = new JButton("登录");
        shi.setBounds(25,60,60,20);
        add(shi);
        shi.addActionListener(new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                login();
            }            
        });
        fou =new JButton("退出");
        fou.setBounds(110,60,60,20);
        add(fou);
        fou.addActionListener(new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                logout();
            }    
        });
        
    }
    void login(){
        String accout = a3.getSelectedItem().toString();
        String pwd = new String(password.getPassword());
        if(accout.equals("huakaihualuo")&&pwd.equals("666666")){
            setVisible(false);
            showMainWindow();
        }else{
            JOptionPane.showMessageDialog(this, "用户名是"+accout + ",密码是" + pwd);
        }
    }
    void logout(){
        int ret = JOptionPane.showConfirmDialog(this,"退出登录？","取消登录",JOptionPane.YES_NO_OPTION);
        if(ret ==JOptionPane.YES_NO_OPTION){
            dispose();
        }
    }
    void showMainWindow(){
        MainWindow frm = new MainWindow();
        frm.setVisible(true);
    }
}








   复选框提供两种状态：选中或未选中。java.awt 包中的Checkbox类用于建立复选框。其相应事件的接口是ItemListener，要想对复选框进行相应就需要实现ItemListener内部的itemStateChanged方法。通过ItemEvent的getItemSelectable可以获得改变的复选框对象，通过getStateChange可以获得改变后的状态。