嵌套类vs实现ActionListener

问题描述

创建实现ActionListener的嵌套类是否有任何好处或缺点：

Are there any benefits or drawbacks to creating a nested class that implements ActionListener:

public class Foo{
    Foo(){
        something.addActionListener(new ButtonListener());
    }
    //...
    private class ButtonListener implements ActionListener{
        public void actionPerformed(ActionEvent e){
            //...
        }
    }
}

与在主类本身中实现ActionListener相比：

versus implementing ActionListener in the main class itself:

public class Foo implements ActionListener{
    Foo(){
        something.addActionListener(this);
    }
    //...
    public void actionPerformed(ActionEvent e){
        //...
    }
}

我经常看到这两个例子，只是想知道是否有最佳做法。

I've seen both examples quite often, and just want to know if there's a 'best practice.'

推荐答案

@Ankur，您仍然可以使用匿名内部类作为您的侦听器，并拥有一个独立的独立控件类，因此具有可维护的代码，我喜欢使用一种技术。例如：

@Ankur, you can still use anonymous inner classes as your listeners and have a separate free-standing control class and thus have code that's quite maintainable, a technique I like to use a bit. For example:

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

public class AnonymousInnerEg {
   private static void createAndShowUI() {
      GuiPanel guiPanel = new GuiPanel();
      GuiControl guiControl = new GuiControl();
      guiPanel.setGuiControl(guiControl);

      JFrame frame = new JFrame("AnonymousInnerEg");
      frame.getContentPane().add(guiPanel);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}

class GuiPanel extends JPanel {
   private GuiControl control;

   public GuiPanel() {
      JButton startButton = new JButton("Start");
      startButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            if (control != null) {
               control.startButtonActionPerformed(e);
            }
         }
      });
      JButton endButton = new JButton("End");
      endButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            if (control != null) {
               control.endButtonActionPerformed(e);
            }
         }
      });

      add(startButton);
      add(endButton);
   }

   public void setGuiControl(GuiControl control) {
      this.control = control;
   }


}

class GuiControl {
   public void startButtonActionPerformed(ActionEvent ae) {
      System.out.println("start button pushed");
   }

   public void endButtonActionPerformed(ActionEvent ae) {
      System.out.println("end button pushed");
   }
}

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