usebutton.java

Java语言

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class UseButton extends Applet implements ActionListener{
	Button btn1,btn2;
	int k=0;
	public void init(){
		setSize(200,300);
		btn1=new Button("画圆");
		btn1.addActionListener(this);
		add(btn1);
		btn2=new Button("清除");
		btn2.addActionListener(this);
		add(btn2);
	}
	public void paint(Graphics g){
		if(k==1){
			g.setColor(Color.blue);
			g.fillOval(60,30,80,80);
		}
		if(k==2){}
	}
	public void actionPerformed(ActionEvent e){
		if(e.getActionCommand()=="画圆")
			k=1;
		if(e.getSource()==btn2)
			k=2;
		repaint();
	}
}