Question

Java 错误 找不到符号

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.lang.String;

public class Calculate
{
public static void main (String[] args)
{
FrameSize frame = new FrameSize();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}
class FrameSize extends JFrame
{
public FrameSize()
{
setSize(600,400); //设置框架尺寸
ButtonPanel panel2 = new ButtonPanel();
Container contentPane = getContentPane();
contentPane.add(panel2);
}
}

//创建按钮面板
class ButtonPanel extends JPanel
{
public ButtonPanel()
{
JButton Button1 = new JButton("0"); //创建按钮
JButton Button2 = new JButton("1");
JButton Button3 = new JButton("2");

add(Button1);
add(Button2);
add(Button3);

ButtonAction ButtonAction1 = new ButtonAction("1"); //40行找不到符号
ButtonAction ButtonAction2 = new ButtonAction("2"); //41行找不到符号
ButtonAction ButtonAction3 = new ButtonAction("3"); //42行找不到符号

Button1.addActionListener(ButtonAction1);
Button2.addActionListener(ButtonAction2);
Button3.addActionListener(ButtonAction3);

}

private class ButtonAction implements ActionListener
{

public void actionPerformed(ActionEvent event)
{
Object source = event.getSource();
if(source == Button1) ButtonText = "0";
else if(source == Button2) ButtonText = "1";
else if(source == Button3) ButtonText = "2";
repaint();
}
}
private JButton Button1;
private JButton Button2;
private JButton Button3;

public String ButtonText=" ";
}

各位高手啊，为什么我的40~42行显示找不到符号的错误呢？

Answer 1

你这BUTTONACTION什么意思啊!?有这么一个语句的吗?

private class ButtonAction implements ActionListener
这个里面,你自己都写了点3个BUTTON的不同情况时候设计BUTTONTEXT的情况了.为什么还要搞3个BUTTONACTION?

试一下把下面3行删除
ButtonAction ButtonAction1 = new ButtonAction("1"); //40行找不到符号
ButtonAction ButtonAction2 = new ButtonAction("2"); //41行找不到符号
ButtonAction ButtonAction3 = new ButtonAction("3"); //42行找不到符号

下面的是改的:
Button1.addActionListener(new ButtonAction() );
Button2.addActionListener(new ButtonAction());
Button3.addActionListener(new ButtonAction());

这样应该能达到你的效果.

Answer 2

因为代码不全,缺少ButtonAction 类,或者你没有import进来

Answer 3

你并没有定义ButtonAction类的构造函数
但在声名对象时却传入了参数，当然不行啊！
例如ButtonAction ButtonAction1 = new ButtonAction("1");中的参数"1"，给删了，能运行
你这个程序是测试程序吗？运行没有实际的效果出现。