| 发表于：2007-01-17 01:19:14 楼主 |
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class buttontest {
public static void main（string[] args){
buttonframe frame=new buttonframe（);
frame.setdefaultcloseoperation（jframe.exit_on_close);
frame.setvisible（true);
}
}
class buttonframe extends jframe{
public buttonframe（){
settitle（ "buttontest ");
setsize（default_width,default_height);
buttonpanel panel=new buttonpanel（);
add（panel);
}
public static final int default_width=300;
public static final int default_height=200;
}
class buttonpanel extends jpanel{
public buttonpanel（){
jbutton yellowbutton=new jbutton（ "yellow ");
jbutton bluebutton=new jbutton（ "blue ");
jbutton redbutton=new jbutton（ "red ");
add（yellowbutton);
add（bluebutton);
add（redbutton);
coloraction yellowaction=new coloraction（color.yellow);
coloraction blueaction=new coloraction（color.blue);
coloraction redaction=new coloraction（color.red);
yellowbutton.addactionlistener（yellowaction);
bluebutton.addactionlistener（blueaction);
redbutton.addactionlistener（redaction);
}
private class coloraction implements actionlistener{
public coloraction（color c){
backgroundcolor=c;
}
public void actionperformed（actionevent event){
setbackground（backgroundcolor);
}
private color backgroundcolor;
}
}
用javac就能成功编译,但用java运行的时候就会出现在的错误:
exception in thread "main " java.lang.error: do not use buttonframe.add（) use but
tonframe.getcontentpane（).add（) instead
at javax.swing.jframe.createrootpaneexception（jframe.java:465)
at javax.swing.jframe.addimpl（jframe.java:491)
at java.awt.container.add（container.java:307)
at buttonframe. <init> （buttontest.java:16)
at buttontest.main（buttontest.java:6)
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