事件处理

Question

如果你真想写，你一定可以写出来
这又不是多难

Answer 1

//Oval.java
import java.awt.*;
import java.awt.event.*;import javax.swing.*;public class Oval extends JFrame implements ActionListener{

Color c=Color.red;

public Oval(){
setSize(400,300);

this.getContentPane().setLayout(new FlowLayout());

JButton b=new JButton("选色");

this.getContentPane().add(b);

b.addActionListener(this);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setVisible(true);
}

public static void main(String[] args){
new Oval();
}

public void paint(Graphics g){
super.paint(g);
g.setColor(c);
g.fillOval(50,80,300,200);
} public void actionPerformed(ActionEvent e){
JColorChooser jcc=new JColorChooser(c);

Color sc=jcc.showDialog(this,"",c);

if(sc!=null){
c=sc;
}

repaint();
}
}