java 图形用户界面 之 用户名和密码输入 示例程序

package J_9_3_01;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class J_9_4_6_User_And_Password
{
public static void main(String [] args)
{
EventQueue.invokeLater(()->
{
JFrame frame=new TotalFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("这是一个用户名和密码输入的测试...");
frame.setVisible(true);
});
}
}

class TotalFrame extends JFrame
{
public final int DEFAULT_WIDTH=600;
public final int DEFAULT_HEIGHT=600;
public TotalFrame()
{
setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
JPasswordField passwordField=new JPasswordField();
JTextField textField=new JTextField();

JPanel northPanel=new JPanel();
northPanel.setLayout(new GridLayout(2,2));
northPanel.add(new JLabel("User Name:",SwingConstants.RIGHT));
northPanel.add(textField);
northPanel.add(new JLabel("Password:",SwingConstants.RIGHT));
northPanel.add(passwordField);

add(northPanel,BorderLayout.NORTH);

JTextArea textArea=new JTextArea(8,20);
JScrollPane scrollPanel=new JScrollPane(textArea);
//注意 scrollPanel.add(textArea);  左侧这个句子不可以代替JScrollPane scrollPanel=new JScrollPane(textArea);
/*
javax.swing.JScrollPane
JScrollPane(Component c)
创建一个滑动窗格，用来显示指定组件的内容。当组件内容超过显示范围时，滚动条会自动出现
不可以用JScrollPane scrollPane=new JScrollPane();
scrollPane.add(textField);来代替
*/
add(scrollPanel,BorderLayout.CENTER);

JPanel southPanel=new JPanel();

JButton insertButton=new JButton("显式账号和密码");
southPanel.add(insertButton);

insertButton.addActionListener(event->textArea.append("User name is :"+textField.getText()+" \nPassword is :"+new String(passwordField.getPassword())+"\n"));

add(southPanel,BorderLayout.SOUTH);

}
}