testcanvas.java

来自「Java与面向对象程序设计实验教学讲义.复数类的实现,复数类的复杂运算,身份证号」· Java 代码 · 共 38 行

import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class TestCanvas extends Canvas implements KeyListener{
	StringBuffer buf = new StringBuffer("Hello!");
	
	public void paint(Graphics g){
		g.drawString(buf.toString(),10,10);  
	}
	
	public void keyTyped(KeyEvent e){
		buf.append("  Hello!");
		repaint();
	}
	
    public void keyPressed(KeyEvent e){  }
	public void keyReleased(KeyEvent e){  }
	
	public static void main(String[] args){
		Frame f = new Frame("Test Canvas");
		f.setSize(400,100);
		f.add(new Label("Please type a key:"),BorderLayout.NORTH);
		
		TestCanvas tc = new  TestCanvas();
		tc.setBackground(Color.green);
		tc.requestFocus();
		tc.addKeyListener(tc);
		f.add(tc,BorderLayout.CENTER);
		
		f.addWindowListener(new WindowAdapter(){
        	public void windowClosing(WindowEvent e){
        		System.exit(0);
        	}
        });
		f.setVisible(true);
	}
}