这个代码的类图该怎么去花啊
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.*;
import javax.swing.JFrame;
public class BaseFrame extends JFrame {
public BaseFrame(String title) {
setLayout(null);
setTitle(title);
setSize(800, 300);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});// 关闭窗口的匿名类
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
}
public void showMe() {
setVisible(true);
}
public static void main(String[] args) {
JPanel j = new JPanel();
BaseFrame f = new BaseFrame("hello");
j.setSize(800, 50);
j.setLayout(new GridLayout(1, 5, 5, 55));
final JTextField t1 = new JTextField();
final JTextField t2 = new JTextField();
final JTextField t3 = new JTextField();
final JComboBox cb = new JComboBox();
cb.addItem("+");
cb.addItem("-");
cb.addItem("*");
cb.addItem("/");
JButton btn = new JButton("=");
j.add(t1);
j.add(cb);
j.add(t2);
j.add(btn);
j.add(t3);
j.setVisible(true);
f.add(j);
f.showMe();
// final String s = cb.getSelectedItem().toString(); 说明 不能首先或、获得cb 的值因为
// 代码的执行从上到下 永远只能获取 到第一个item “+” 而 后面的事件记录无法实现
btn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (cb.getSelectedItem().toString().equals("+")) {
int c = 0;
int num1 = Integer.parseInt(t1.getText());
int num2 = Integer.parseInt(t2.getText());
c = num1 + num2;
String s1 = Integer.toString(c);
t3.setText(s1);
} else if (cb.getSelectedItem().toString().equals("-")) {
int c = 0;
int num1 = Integer.parseInt(t1.getText());
int num2 = Integer.parseInt(t2.getText());
c = num1 - num2;
String s1 = Integer.toString(c);
t3.setText(s1);
} else if (cb.getSelectedItem().toString().equals("*")) {
int c = 0;
int num1 = Integer.parseInt(t1.getText());
int num2 = Integer.parseInt(t2.getText());
c = num1 * num2;
String s1 = Integer.toString(c);
t3.setText(s1);
} else if (cb.getSelectedItem().toString().equals("/")) {
int c = 0;
int num1 = Integer.parseInt(t1.getText());
int num2 = Integer.parseInt(t2.getText());
c = num1 / num2;
String s1 = Integer.toString(c);
t3.setText(s1);
} else {
System.out.print("No");
}
}
});
}
}