lifecycledemo.java

来自「《java事件处理指南》一书的代码,好东西」· Java 代码 · 共 68 行

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class LifeCycleDemo extends JFrame 
{
   MyButton button; 

   public LifeCycleDemo()
   {
/*  A user-defined JButton is created and placed on a JFrame.   */

      button = new MyButton("help");

      JPanel centerPanel = new JPanel();
      centerPanel.add(button);

      getContentPane().add(centerPanel, BorderLayout.CENTER);

      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setBounds(100, 100, 300, 200);
      setVisible(true);
   }

   public static void main(String args[])
   {
      LifeCycleDemo demo = new LifeCycleDemo();
   }
}

/*   The MyButton class is a JButton that is given some added    */
/*   functionality by overriding the processMouseEvent() method  */

class MyButton extends JButton
{
   public MyButton(String label)
   {
      super(label);
      setForeground(Color.black);
      setBorder(BorderFactory.createCompoundBorder(
                   BorderFactory.createRaisedBevelBorder(), 
                   BorderFactory.createEmptyBorder(10,10,10,10)));
      setFont(new Font("Serif", Font.BOLD, 12));
   }

/*   The processMouseEvent() method is overridden to change the color   */
/*   of the button label when the user presses it.  When the button is  */
/*   released, the label color is re-set to be black.  This change      */
/*   happens regardless of whether the MouseEvent is sent to a          */
/*   listener or not.  After the label color change, the                */
/*   processMouseEvent() method from the Component class is called to   */
/*   perform the normal MouseEvent processing.                          */ 

   protected void processMouseEvent(MouseEvent event)
   {
      if ( event.getID() == MouseEvent.MOUSE_PRESSED )
      {
         setForeground(Color.red);
      }
      if ( event.getID() == MouseEvent.MOUSE_RELEASED )
      {
         setForeground(Color.black);
      }
      super.processMouseEvent(event);
   }
}