New to GUI, need help with actionListener and buttons

[D Heaney]

I'm trying to use the same actionlistener for multiple buttons (two to start with). Here is my code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class SimpleGuiB implements ActionListener {
JButton button;
JButton button1;
String zeroString = "button0";
String oneString = "button1";
public static void main(String[] args)
{
SimpleGuiB gui = new SimpleGuiB();
gui.go();
}
public void go()
{
JFrame frame = new JFrame();
button = new JButton("click me");
button.setActionCommand(zeroString);
button1 = new JButton("Click me too");
button1.setActionCommand(oneString);
button.addActionListener(this);
button1.addActionListener(this);
frame.getContentPane().add(BorderLayout.SOUTH, button);
frame.getContentPane().add(BorderLayout.CENTER, button1);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300,300);
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
if(e.getActionCommand() == "button0")
{
button.setText("clicked!");
}
else if (e.getActionCommand() == "button1")
{
button1.setText("clicked!");
}
else
{
//
}
}
}

Is there any way I can tell which button was pressed in the actionPerformed method? Instead of the way I'm doing it just now. I don't want to have to add an if statement for every button I create, I've been looking around for a while but can't seem to find anything.
Thanks in advance..

[Ranganathan Kaliyur Mannar]

Better to use the getSource() method (this compares against the instance and not string values):

if(e.getSource() == button) {

[Nam Ha]

Hi Foamy Caramel,

I think you should use a common action listener if all the buttons do the same thing, regardless of buttons.
I prefer using separate action listeners for each buttons, and wrap the common things into a method.

[A Thakur]

There are 2 ways of implementing ActionListener:

Option 1: To have common ActionListener Implemented

public class TestButton implements ActionListener{
private static final String OPEN_DIRECTORY = "open directory";
private static final String OPEN_FILE = "open file";
public static void main(String[] args) {
new TestButton().showUI();
}
private void showUI(){
JFrame frame = new JFrame("Book Tree");
frame.getContentPane().add(get_btnOpenDirectory(), BorderLayout.EAST);
frame.getContentPane().add(get_btnOpenFile(), BorderLayout.CENTER);
frame.setSize(300, 300);
frame.setVisible(true);
}
private JButton get_btnOpenDirectory(){
JButton _btnOpenDirectory = new JButton(OPEN_DIRECTORY);
_btnOpenDirectory.addActionListener(this);
return _btnOpenDirectory;
}
private JButton get_btnOpenFile(){
JButton _btnOpenFile = new JButton(OPEN_FILE);
_btnOpenFile.addActionListener(this);
return _btnOpenFile;
}
@Override
public void actionPerformed(ActionEvent e) {
Component source = null;
String srcAction = "";
source = (JButton)(e.getSource());
srcAction = ((JButton)source).getText();
System.out.println(srcAction);
if(srcAction.equalsIgnoreCase(OPEN_DIRECTORY)){
System.out.println("open directory");
}else if(srcAction.equalsIgnoreCase(OPEN_FILE)){
System.out.println("open file");
}
}
}

OPTION 2: To have individual actionlisteners

private JButton get_btnOpenDirectory(){
JButton _btnOpenDirectory = new JButton(OPEN_DIRECTORY);
_btnOpenDirectory.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
System.out.println("Clciking OPEN_DIRECTORY");
}
});
return _btnOpenDirectory;
}
private JButton get_btnOpenFile(){
JButton _btnOpenFile = new JButton(OPEN_FILE);
_btnOpenFile.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
System.out.println("Clciking OPEN_FILE");
}
});
return _btnOpenFile;
}

See which one is better for you. Both approaches have same end-results.

Thanks.

[Campbell Ritchie]

The version with one listener and getSource() is by no means object-oriented programming, even though you see it in many books.