JFrame-ActionListener

Question

I'm working on building a program that uses JFrame. What I want for my end result, is to implement an ActionListener which will remove labels when the user clicks a button. For example: when the user clicks the JButton, one of 5 labels is removed from the frame. When they click the button again, one of the remaining 4 labels is removed...and so on a so forth, until 0 labels remain. Technically, I have the program working as required however, I'm trying to see if there is a way to implement the ActionListener event via a loop as opposed to listing an if statement for each individual label. Thank you so much!

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

//calls for public class to inherit features of JFrame within Java
public class NoPurchaseReason extends JFrame implements ActionListener {

private int removeText = 0;

JButton btn = new JButton("Select");

JLabel lbl = new JLabel("Found better price");
JLabel lbl1 = new JLabel("Not as shown on website");
JLabel lbl2 = new JLabel("Wrong product");
JLabel lbl3 = new JLabel("Damaged upon delivery");
JLabel lbl4 = new JLabel("None of the above");

public static void main(String[] args) {
    JFrame f = new NoPurchaseReason("Please tell us why you wish to return your purchase.");
    f.setBounds(300, 100, 500, 500);
    f.setVisible(true);
    f.setBackground(Color.blue);
}

public NoPurchaseReason(String title) {
    super(title);
    setLayout(null);
    lbl.setBounds(40, 40, 600, 40);
    btn.setBounds(320, 10, 80, 20);
    lbl.setBounds(100, 40, 100, 20);
    lbl1.setBounds(100, 70, 100, 20);
    lbl2.setBounds(100, 100, 150, 20);
    lbl3.setBounds(100, 130, 100, 20);
    lbl4.setBounds(100, 160, 100, 20);

    add(btn);
    add(lbl);
    add(lbl);
    add(lbl1);
    add(lbl2);
    add(lbl3);
    add(lbl4);
    btn.addActionListener(this);
}

public void actionPerformed(ActionEvent e) {
    removeText++;
    if (removeText == 1) {
        lbl.setVisible(false);
        lbl1.setBounds(100, 40, 100, 20);
        lbl2.setBounds(100, 70, 100, 20);
        lbl3.setBounds(100, 100, 150, 20);
        lbl4.setBounds(100, 130, 100, 20);
    }
    if (removeText == 2) {
        lbl1.setVisible(false);
        lbl2.setBounds(100, 40, 100, 20);
        lbl3.setBounds(100, 70, 150, 20);
        lbl4.setBounds(100, 100, 100, 20);
    }
    if (removeText == 3) {
        lbl2.setVisible(false);
        lbl3.setBounds(100, 40, 150, 20);
        lbl4.setBounds(100, 70, 100, 20);
    }
    if (removeText == 4) {
        lbl3.setVisible(false);
        lbl4.setBounds(100, 40, 100, 20);
    }
    if (removeText == 5) {
        lbl4.setVisible(false);
    }
}

}

Answer 1

Learning how to properly use layout managers will save you a lot of trouble in the long run.

You'll also find that people will tell you to adhere to the single responsibility principle , and avoid making classes that violate this principle (eg, extending JFrame and implementing ActionListener).

You'll also hear folks tell you to prefer using actions over action listeners (if you need to share functionality across multiple components, that is).

A simple way would be to dedicate an entire panel to holding your labels, and simply remove the first label in the panel until there are no more labels. Here's an example:

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

class LabelDemo
{
    public static void main(String[] args) {
        String[] labels = {
                "Found better price",
                "Not as shown on website",
                "Wrong product",
                "Damaged upon delivery",
                "None of the above"
        };
        final JFrame frame = new JFrame();
        final JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
        for (String s: labels) {
            panel.add(new JLabel(s));
        }
        frame.add(panel);
        JButton button = new JButton("Select");
        button.addActionListener(new ActionListener() {
            @Override public void actionPerformed(ActionEvent e) {
                if (panel.getComponentCount() > 0)
                    panel.remove(0);
                frame.repaint();
            }
        });
        frame.add(button, BorderLayout.NORTH);
        frame.pack();
        frame.setVisible(true);
    }
}

Also, you may just have a certain goal in mind that I'm not aware of, but it honestly seems like a list would be better in this case. Here's an example of that as well:

String[] labels = {
        "Found better price",
        "Not as shown on website",
        "Wrong product",
        "Damaged upon delivery",
        "None of the above"
};
JList<String> list = new JList<>(labels);
int option = JOptionPane.showConfirmDialog(null, list, 
        "Please tell us why you wish to return your purchase.", 
        JOptionPane.OK_CANCEL_OPTION);
if (option == JOptionPane.OK_OPTION) {
    String selectedValue = list.getSelectedValue();
    System.out.println(selectedValue); // Do something with it.
}