eventdemo2.java

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import java.awt.*;
import java.awt.event.*;
import javax.swing.*; 
public class EventDemo2 extends JFrame
{
   private JButton button;
   private Container container;   //声明内容面板
   
   public EventDemo2() 
   {
	   super("EventDemo2");
       setSize(300,200); 
       try
       {   //系统外观
 		 UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
 	   }catch(Exception e){}
 	  
       //获取内容面板
       container = getContentPane();
       
       //创建按钮
       button = new JButton("改变颜色");
       button.setFont(new Font("Serif", Font.PLAIN, 14));
       
       //注册监听器
       button.addActionListener(new EventHandler());
       container.add(button, BorderLayout.SOUTH);  //向面板中加入按钮组件
      
       setVisible(true);  //设置窗口为可见
       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
   
    public static void main(String[] arguments)
    {
       EventDemo2 application = new EventDemo2();     
    }
    
    class EventHandler implements ActionListener     //自定义内部类，实现ActionListener接口
    {
    	public void actionPerformed(ActionEvent event)   //处理事件的方法
    	{
    		int red = (int)(Math.random() * 256);
  		    int green = (int)(Math.random() * 256);
  		    int blue = (int)(Math.random() * 256);
  		    container.setBackground(new Color(red, green, blue));
    	}
    }
}