一个简单的计算器界面实现

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Calculator extends JFrame
{
    JButton backSpace, clearUp;

    JTextField display;

    JPanel p1, p2;

    public Calculator()
    {
        backSpace = new JButton("BackSpace");
        clearUp = new JButton("ClearUp");
        backSpace.setForeground(Color.RED);
        clearUp.setForeground(Color.RED);
        display = new JTextField("0");
        display.setEditable(false);
        display.setBackground(Color.WHITE);
        display.setHorizontalAlignment(JTextField.RIGHT);
        p1 = new JPanel();
        p1.setLayout(new FlowLayout());
        p1.add(backSpace);
        p1.add(clearUp);
        p2 = new JPanel();
        p2.setLayout(new GridLayout(4, 5));
        String buttons = "779/a456*b123-%0.c+=";
        for (int i = 0; i < buttons.length(); i++)
        {
            char temp = buttons.charAt(i);
            addButton(p2, temp);
        }
        this.addWindowListener(new WindowAdapter()
        {
            @Override
            public void windowClosing(WindowEvent e)
            {
                System.exit(0);
            }
        });
        this.setTitle("Calculater");
        this.setLayout(new BorderLayout());
        this.add(display, BorderLayout.NORTH);
        this.add(p1, BorderLayout.CENTER);
        this.add(p2, BorderLayout.SOUTH);
        this.pack();
        this.setResizable(false);
        this.setVisible(true);
    }

    private void addButton(Container c, char temp)
    {
        String bText = null;
        switch (temp)
        {
        case 'a':
            bText = "Sqrt";
            break;
        case 'b':
            bText = "1/x";
            break;
        case 'c':
            bText = "-/+";
            break;
        default:
            bText = String.valueOf(temp);
            break;
        }

        JButton b = new JButton(bText);
        b.setForeground(Color.blue);
        c.add(b);
    }

    public static void main(String[] args)
    {
        new Calculator();
    }
}