通讯记录系统1(密码登陆窗体)

import java.awt.*;import java.awt.event.*;import javax.swing.*;

public class Login{        public static void main(String[] args)        {                LoginFrame loginFrame=new LoginFrame();                loginFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);                loginFrame.show();        }}class LoginFrame extends JFrame{        public LoginFrame()        {                setTitle("通讯记录系统");                setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);                Toolkit kit=Toolkit.getDefaultToolkit();                Dimension screenSize=kit.getScreenSize();                //为什么这里不能定义私有变量呢？？？                int screenWidth=screenSize.width;                int screenHeight=screenSize.height;                setLocation(screenWidth/2-DEFAULT_WIDTH/2,screenHeight/2-DEFAULT_HEIGHT/2);                Box b=Box.createVerticalBox();                Container contentPane=getContentPane();                //contentPane.setLayout(new GridLayout(5,4));                //gridLayout=new GridLayout(4,1);                //loginPanel=new JPanel(gridLayout);                nameL=new JLabel("用户名：");                nameT=new JTextField(8);                passwordL=new JLabel("密　码：");                passwordT=new JTextField(8);                okB=new JButton("进入");                canncelB=new JButton("退出");                ///添加button事件                okB.addActionListener(new ActionListener(){                        public void actionPerformed(ActionEvent event){                                                        }                }                );                                canncelB.addActionListener(new ActionListener(){                        public void actionPerformed(ActionEvent event){                                System.exit(0);                        }                }                );                ///添加组建                b.add(Box.createRigidArea(new Dimension(300,10)));                nameP=new JPanel(new FlowLayout());                nameP.add(nameL);                nameP.add(nameT);                b.add(nameP);                b.add(Box.createRigidArea(new Dimension(300,10)));                passwordP=new JPanel(new FlowLayout());                passwordP.add(passwordL);                passwordP.add(passwordT);                b.add(passwordP);                b.add(Box.createRigidArea(new Dimension(300,10)));                buttonP=new JPanel(new FlowLayout());                buttonP.add(okB);                buttonP.add(canncelB);                //no pointer                 b.add(buttonP);                contentPane.add(b,BorderLayout.CENTER);                //contentPane.add(buttonP,BorderLayout.SOUTH);                //contentPane.add(loginPanel,BorderLayout.CENTER);        }                //窗口大小定义                private int DEFAULT_WIDTH=300;                private int DEFAULT_HEIGHT=200;                //组件定义                private JLabel nameL;                private JLabel passwordL;                private JTextField nameT;                private JTextField passwordT;                private JButton okB;                //加组件的面板                private JButton canncelB;                private JPanel buttonP;                private JPanel nameP;                private JPanel passwordP;                //private JPanel loginPanel;                //private GridLayout gridLayout;}