addActionListener(new ActionListener()问题

Question

import java.awt.*;

import java.awt.event.*;

public class Circle {

Frame f;

Label l1,l2;

TextField tf1,tf2;

Panel p1,p2,p3,p4;

Button b1;

public static void main(String[] args) {

new Circle();

// TODO Auto-generated method stub

}

Circle(){

f=new Frame("这是窗体的名字");

l1=new Label("圆的半径：");

l2=new Label("圆的面积");

tf1=new TextField(20);

tf2=new TextField(20);

b1=new Button("计算");

p1=new Panel();

p2=new Panel();

p3=new Panel();

p4=new Panel();

b1.addActionListener(new ActionListener()//这句话一直报错

{

public void Actionperformed(ActionEvent e)

{

int i;

i=Integer.parseInt(tf1.getText());

tf2.setText(String.valueOf(3.1415926*2*i));

}

});

p1.add(b1);

p2.add(l1);p2.add(tf1);

p3.add(l2);p3.add(tf2);

p4.add(p3);p4.add(p1);

f.add(p2,BorderLayout.NORTH);

f.add(p4,BorderLayout.CENTER);

f.setVisible(true);

f.setSize(400, 170);

f.setLocation(350, 450);

f.addWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e) {

System.exit(0);

}

}

);

}

}

Answer 1

你没有实现ActionListener接口的方法-->方法名写错了Actionperformed()应该是actionPerformed()