circlesize.java

来自「Java 入门书的源码」· Java 代码 · 共 36 行

//Copyright (c) 1998, Arthur Gittleman
//This example is provided WITHOUT ANY WARRANTY either expressed or implied.

// Debugging Exercise -- Has Errors

            import java.awt.event.*;
            public class CircleSize extends Frame{ 
                int width=50, height=50;
                int x=140, y=90;
                public CircleSize()  {
                    addKeyListener(this);
                    addWindowListener(this);
                }
                public void paint(Graphics g) {
                    g.drawOval(x,y,width,height);  
                }
                public void keyPressed(KeyEvent e) {
                    int i = e.getKeyCode();
                    if (i==KeyEvent.VK_B) {width+=6; height+=6; x-=3; y-=3;}
                    else if (i==KeyEvent.VK_S) {width-=6; height-=6; x+=3; y+=3;}
                    repaint();
                }
                public void keyTyped(KeyEvent e) {}
                    public static void main(String[] args) {
                        CircleSize cs = new CircleSize();
                        cs.setSize(300,200);
                        cs.show();
                    }
               class WindowHandler extends WindowAdapter {
                  public void widowClosing(WindowEvent e) {
                      System.exit(0);
                  }
               }
            }