java--加法的实现

import java.awt.*;
import java.awt.event.*;


public class TFMath
{
public static void main(String[] args)
{
new TFrame().LaunchFrame();
}
}
class TFrame extends Frame
{
public void LaunchFrame()
{
TextField num1 = new TextField(10);//新建能容纳10个字符的TextField
TextField num2 = new TextField(10);
TextField num3 = new TextField(15);
Label lb = new Label("+");
Button b = new Button("=");
b.addActionListener(new listener(num1,num2,num3));
setLayout(new FlowLayout());
add(num1);
add(lb);
add(num2);
add(b);
add(num3);
pack();
setVisible(true);
}
}
class listener implements ActionListener
{
TextField num1, num2, num3;
listener(TextField num1,TextField num2,TextField num3)
{
this.num1 = num1;//在一个类中引用另一个类的变量使用参数传递的方法
this.num2 = num2;//但是这种方法效率低，而且当参数多的时候不好整
this.num3 = num3;
}
public void actionPerformed(ActionEvent e)
{
int n1 = Integer.parseInt(num1.getText());
int n2 = Integer.parseInt(num2.getText());
num3.setText(""+(n1+n2));
}
}