第二篇学习笔记

import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;

public class D2 {
    public static void main(String[] args){
        EventQueue.invokeLater(new Runnable(){
            public void run(){
                JFrame frame = new Register();
                frame.setTitle("班级管理系统");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}
class Register extends JFrame{
    private static final long serialVersionUID = 1L;
    private JPanel all = new JPanel();
    private JComboBox jcb = new JComboBox();
    private JPasswordField pwf = new JPasswordField(10);
    
    
    
    private JButton confirm = new JButton("确定");
    private JButton cancel = new JButton("取消");
    
    Register(){
        GridLayout Gl = new GridLayout(3,2,30,10);
        
        all.setLayout(Gl);
        
        addU();
        addP();
        addB();
        add(all);
        pack();
    }
    private void addU(){
        jcb.addItem("导员");
        jcb.addItem("班长");
        jcb.addItem("学委");
        jcb.addItem("团支");
        jcb.addItem("学生");
        jcb.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent a3){
                
            }
        });
        all.add(new Label("请输入用户名"));
        all.add(jcb);
    }
    private void addP(){
        all.add(new Label("请输入密码"));
        all.add(pwf);
    }
    private void addB(){
        confirm.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent a1) {
                String p = new String(pwf.getPassword());
                String s = (String)jcb.getSelectedItem();
                JOptionPane.showMessageDialog(null,"你选择的职务:"+s+"  你输入的密码:"+p);
            }
        });
        cancel.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent a2){
                JOptionPane.showMessageDialog(null,"退出");
                dispose();
            }
        });
        all.add(confirm);
        all.add(cancel);
    }
    
}