testingcanvas.java

一个画布,的例子.Canvas,画布为应用程序提供了绘图功能.

//例12_14  使用画布的例子
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class TestingCanvas extends Canvas implements KeyListener,WindowListener{
  String s="";
  public void paint(Graphics g){
     g.setColor(Color.blue);    
     g.drawRect(50,50,100,100);
     g.drawString("你好",60,60);
  }	
  public void keyTyped(KeyEvent ev) {
    requestFocus();
    s+=ev.getKeyChar();
    getGraphics().drawString(s,30,20);
  }
   public void keyPressed(KeyEvent ev) {
		System.out.println("KeyPressed");  } 
   public void keyReleased(KeyEvent ev) {
		System.out.println("KeyReleased");  }
   public void windowClosing(WindowEvent e) {  
	             System.exit(1);  		}
   public void windowOpened(WindowEvent e) {}
   public void windowIconified(WindowEvent e) {}
   public void windowDeiconified(WindowEvent e) {}
   public void windowClosed(WindowEvent e) {}
   public void windowActivated(WindowEvent e) {}
   public void windowDeactivated(WindowEvent e) {}

   public static void main(String args[]) {
       Frame f=new Frame("testingCanvas");
       TestingCanvas c=new TestingCanvas();
       c.addKeyListener(c);
       f.addWindowListener(c);
       f.add(c,"Center");
       f.setSize(200,200);
       f.setVisible(true);
}
}