draw.java

来自「用JAVA编写的一个简单APPLET程序 实现画圆和画方两个简单功能 具体有读」· Java 代码 · 共 60 行

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

class MyCanvas extends Canvas{//画布类的子类
	int n=-1;
	MyCanvas(){
		setSize(400,300);
		setBackground(Color.gray);
	}
	
	public void setN(int n){
		this.n=n;
	}
	
	public void paint(Graphics g){//重写PAINT()方法
		if(n==0){
			g.drawRect(10, 10, 60, 60);//画正方形框
			setForeground(Color.orange);
		}
		else if(n==1){
			g.drawRect(100, 100,100,100);
			setForeground(Color.RED);
			g.fillRoundRect(100, 100, 100, 100, 100, 100);//画填充圆
			setForeground(Color.RED);
		}
	}	
}

public class Draw extends Applet implements ActionListener{//继承APPLET类的同时实现了监听器
	Button b1,b2;
	MyCanvas canvas;
	
	public void init(){
		canvas=new MyCanvas();
		b1=new Button("画正方形");
		b1.addActionListener(this);
		b2=new Button("画填充圆");
		b2.addActionListener(this);
		add(canvas);
		add(b1);
		add(b2);
		setSize(400,350);		
	}
	
	public void actionPerformed(ActionEvent e){//实现监听的方法
		if(e.getSource()==b1){
			canvas.setN(0);
			canvas.repaint();
			b1.setVisible(false);
			b2.setVisible(true);
		}
		else if(e.getSource()==b2){
			canvas.setN(1);
			canvas.repaint();
			b2.setVisible(false);
			b1.setVisible(true);
		}
	}
}