请帮忙看下这代码哪错了啊,我是新手搞不懂啊,弄了半天了!
import java.awt.*;
import java.awt.event.*;
public class MyButton {
public static void main(String[] args) {
MyFrame f=new MyFrame();
f.show();
}
}
class MyFrame extends Frame{
public MyFrame(){
setTitle("测试按钮");
setSize("200,300");
MB p=new MB();
add(p);
}
}
class MB extends Panel{
public MB(){
MB a=new MB("蓝色");
MB b=new MB("红色");
MB c=new MB("黄色");
add(a);
add(b);
add(c);
MLA a1=new MLA("blue");
MLA b1=new MLA("red");
MLA c1=new MLA("yellow");
a.addActionListener(a1);
b.addActionListener(b1);
c.addActionListener(c1);
}private class MLA implements ActionListener{
private Color bgColor;
public MLA(Color c){
bgColor=c;
}public void actionPerformed(ActionEvent event){
setBackground(bgColor);
}
}
}
import java.awt.*;
import java.awt.event.*;
public class MyButton {
public static void main(String[] args) {
MyFrame f=new MyFrame();
f.show();
}
}
class MyFrame extends Frame{
public MyFrame(){
setTitle("测试按钮");
setSize("200,300");
MB p=new MB();
add(p);
}
}
class MB extends Panel{
public MB(){
MB a=new MB("蓝色");
MB b=new MB("红色");
MB c=new MB("黄色");
add(a);
add(b);
add(c);
MLA a1=new MLA("blue");
MLA b1=new MLA("red");
MLA c1=new MLA("yellow");
a.addActionListener(a1);
b.addActionListener(b1);
c.addActionListener(c1);
}private class MLA implements ActionListener{
private Color bgColor;
public MLA(Color c){
bgColor=c;
}public void actionPerformed(ActionEvent event){
setBackground(bgColor);
}
}
}
你没有预先得到一个容器
应该这样写:
class MyFrame extends Frame{
public MyFrame(){
Container container = this.getContentPane();
setTitle("测试按钮");
setSize("200,300");
MB p=new MB();
container.add(p);
}
这段code 仅提供参考!!!
}