Thread: Question About Best Practice for ActionListener With Multiple Buttons

So if you have a program with 4-6 buttons on a toolbar is it better to give them each their own ActionListener with embedded ActionPerformed/ActionEvent handlers or should you implement an action listener then use one actionPerformed method to catch them all?

In short...This....

JButton button1 = new JButton("1");
   button1.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
         ...
       }
    });

or something like this....

open_btn.addActionListener(this);
close_btn.addActionListener(this);
...
public void actionPerformed(ActionEvent e){
   if(e.getSource() == close_btn){
      System.exit(0);
   }else if(e.getSource() == open_btn){
   ...
   }
}

As long as the code works as expected and is easily readable then either would be fine.

I believe the first approach is more widely used, though at least one programmer I respect said they never use anonymous inner classes. I'm not sure they had a good reason or whether it just boiled down to personal preference.

Using 'this' as the actionListener as in the second approach is definitely the less elegant, used more typically by less experienced programmers, but the same code using a separate class - even an inner class - would be an improvement and just fine.

Thanks for the quick responses. I figured it would boil down to a opinion thing. I have 6 buttons on a toolbar and the build method for it is starting to get longer and longer as I code each button and add the listeners. I wasn't sure if it would be a faux pas to just make one method with if else statements to clean up the toolbar construction method or not.

Originally Posted by GregBrannon

Using 'this' as the actionListener as in the second approach is definitely the less elegant, used more typically by less experienced programmers, but the same code using a separate class - even an inner class - would be an improvement and just fine.

I guess I will steer away from this and create a class just to implement the actionlistener. It just seemed easier and much less code to do it that way. Plus then I was able to easily pass the JFrame as an object to change the status text on the bottom of it. I will rejigger the code a bit see if I can remove the this reference without adding too much complexity. To be fair though, I am the less experienced programmer that you speak of

Thanks again all!
Omega

You could also move the creation of annonymous action listeners to a helper method if you dont want to blow up your GUI creation method.

for example something like this:

public void initGUI() {
     Button btnFile = new Button();
     btn.addActionListener(get_file_actionListener());
 
     Button btnEdit = new Button();
     btn.addActionListener(get_edit_actionListener());
 
     Button btnAbout = new Button();
     btn.addActionListener(get_about_actionListener());
 
     Button btnHelp = new Button();
     btn.addActionListener(get_help_actionListener());
}
 
private ActionListener get_file_actionListener() {
     return new ActionListener() { ... };
}
 
private ActionListener get_edit_actionListener() {
     return new ActionListener() { ... };
}
 
private ActionListener get_about_actionListener() {
     return new ActionListener() { ... };
}
 
private ActionListener get_help_actionListener() {
     return new ActionListener() { ... };
}

Could maybe help to improve readability although in total it would be slightly more code. Still less code then creating a new actual class for each listener.