example4_9.java

书中的例题

   //实现了三个接口
import java.awt.*;
import java.awt.event.*;
public class Example4_9 
  implements MouseMotionListener,MouseListener,WindowListener
 { 
  private Frame win;
  private TextField text; 
  public static void main(String args[])
   {
     Example4_9 w = new Example4_9();
     w.toWin(); 
   } 
  public void toWin()
  {
   win = new Frame("实现三个接口的示例"); 
   win.add(new Label("点击并拖曳鼠标"),"North");
   text = new TextField(30);
   win.add(text,"South"); //使用缺省的边界布局管理器
   win.addMouseMotionListener(this); //注册监听器MouseMotionListener
   win.addMouseListener(this); //注册监听器MouseListener
   win.addWindowListener(this); //注册监听器WindowListener
   win.setSize(300,200);
   win.setVisible(true); 
  }
  public void mouseDragged (MouseEvent e)
  { 
   //实现mouseDragged方法
   String s = "拖曳鼠标 : X="+e.getX()+"  Y = "+e.getY();
   text.setText(s);
  }

  public void mouseEntered(MouseEvent e)
  {
    String s = "鼠标进入";
    text.setText(s);
  }
  public void mouseExited(MouseEvent e)
  {
   String s = "鼠标离开";
   text.setText(s);
  } 
 //为了使窗口能正常关闭，程序正常退出，需要实现windowClosing方法
  public void windowClosing(WindowEvent e)
  { 
   System.exit(1);
  }
  //对不使用的方法其方法体为空，但必须列出来  
  public void mouseMoved(MouseEvent e){  } 
  public void mouseClicked(MouseEvent e){  }
  public void mousePressed(MouseEvent e){}
  public void mouseReleased(MouseEvent e){ }
  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) {}
 }