Thread: Simple TextListener Problem =/ Please help!

The goal of this program is pretty modest:

There's a TextField, and a TextListener attached. So everytime the TextField is edited at all, textValueChanged(TextEvent e) method is triggered. This works fine.

What I need to do, is every time the event is triggered, I need to compare the text in the TextField to a list of keywords. However, for some reason, if the text in the TextField is "a", (TextField.getText() == "a") returns false! Why!!!

Here's my program, with an example of the issue:

import java.awt.*;
import java.awt.event.*;
 
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
 
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;
 
import java.text.*;
 
public class FormattedTextFieldDemo extends JPanel
                                    implements TextListener {
 
    private TextField textField;
 
    public FormattedTextFieldDemo() {
        super(new BorderLayout());
 
        textField = new TextField(10);
        textField.addTextListener(this);
 
        JPanel labelPane = new JPanel(new FlowLayout());
        labelPane.add(textField);
 
        add(labelPane, BorderLayout.NORTH);
 
    }
 
    /**
     * THIS IS THE PROBLEM.
     **/
    public void textValueChanged(TextEvent e) {
 
        String currentText = textField.getText().toString();
 
        if (currentText == "a"  || currentText == "a ") {
            System.out.print("it's a!");
        } else {
            System.out.print("it's not a.");
        }
    }
 
    private static void createAndShowGUI() {
        JFrame frame = new JFrame("Austin's Program");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
        frame.add(new FormattedTextFieldDemo());
        frame.setSize(new Dimension(200,200));
        frame.setVisible(true);
    }
 
    public static void main(String[] args) {
        createAndShowGUI();
    }
}

Reading: Java: String Comparison

Chris

It works! Thank you so much. I was wondering if it had something to do with deep vs shallow equality. Too new with Java to know much about it though.