首先我给出源程序:
下面是第一个类:
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
class ToggleButton extends Button implements ActionListener
{
private String label1; //two labels to toggle between
private String label2;
public ToggleButton(String s1,String s2) //构造函数
{
super(s1); //call Button's constructor to set the label
label1=s1; //Set my two labels
label2=s2;
addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
String temps=label1; //swap the labels
label1=label2;
label2=temps;
setLabel(label1);
}
}
下面是第2个类:
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class ToggleTest extends Applet implements ActionListener
{
private ToggleButton lightSwitch;
public void init()
{
lightSwitch=new ToggleButton("off","on");
add(lightSwitch);
lightSwitch.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
showStatus("The Light is"+lightSwitch.getLabel());
}
}
这个程序编译的时候没有问题,但是在运行的时候说:
--------------------Configuration: ToggleButton - j2sdk1.4 <Default> - <Default>--------------------
Initializing jdb ...
> run sun.applet.AppletViewer ToggleButton.htm
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
>
VM Started: 载入:无法实例化 ToggleButton.class。
java.lang.InstantiationException: ToggleButton
at java.lang.Class.newInstance0(Class.java:293)
at java.lang.Class.newInstance(Class.java:261)
at sun.applet.AppletPanel.createApplet(AppletPanel.java:619)
at sun.applet.AppletPanel.runLoader(AppletPanel.java:548)
at sun.applet.AppletPanel.run(AppletPanel.java:299)
at java.lang.Thread.run(Thread.java:534)
谁能帮我解决一下吗?
下面是第一个类:
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
class ToggleButton extends Button implements ActionListener
{
private String label1; //two labels to toggle between
private String label2;
public ToggleButton(String s1,String s2) //构造函数
{
super(s1); //call Button's constructor to set the label
label1=s1; //Set my two labels
label2=s2;
addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
String temps=label1; //swap the labels
label1=label2;
label2=temps;
setLabel(label1);
}
}
下面是第2个类:
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class ToggleTest extends Applet implements ActionListener
{
private ToggleButton lightSwitch;
public void init()
{
lightSwitch=new ToggleButton("off","on");
add(lightSwitch);
lightSwitch.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
showStatus("The Light is"+lightSwitch.getLabel());
}
}
这个程序编译的时候没有问题,但是在运行的时候说:
--------------------Configuration: ToggleButton - j2sdk1.4 <Default> - <Default>--------------------
Initializing jdb ...
> run sun.applet.AppletViewer ToggleButton.htm
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
>
VM Started: 载入:无法实例化 ToggleButton.class。
java.lang.InstantiationException: ToggleButton
at java.lang.Class.newInstance0(Class.java:293)
at java.lang.Class.newInstance(Class.java:261)
at sun.applet.AppletPanel.createApplet(AppletPanel.java:619)
at sun.applet.AppletPanel.runLoader(AppletPanel.java:548)
at sun.applet.AppletPanel.run(AppletPanel.java:299)
at java.lang.Thread.run(Thread.java:534)
谁能帮我解决一下吗?
解决方案 »
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