Question

I am making a frame with 3 panels. 1 panel has some text on it, 1 has radio buttons to alter the font that the saying appears in and the last panel has radio buttons to alter the size of the font. I have everything done, but I am confused as to how to add the action listener for the size radio buttons. Can anyone help me with this? The code for the actionlistener is near the bottom. Thank you very much!

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

public class Layouts extends JPanel implements ActionListener
{
    int style = Font.PLAIN;
    String font = "Arial";
    private JLabel saying, overAll, top, sizeP, fontP;
    private JPanel panel1, panel2, panel3, panel4;
    private JRadioButton style1, style2, style3, style4, size1, size2, size3, size4;
    //-----------------------------------------------------------------
    //  Sets up a panel with a label and some check boxes that
    //  control the style of the label's font.
    //-----------------------------------------------------------------
    public Layouts()
    {
        style1 = new JRadioButton ("Arial", true);
        style2 = new JRadioButton ("Times New Roman", false);
        style3 = new JRadioButton ("Verdana", false);
        style4 = new JRadioButton ("Thonburi", false);

        size1 = new JRadioButton ("36", false);
        size2 = new JRadioButton ("24", false);
        size3 = new JRadioButton ("20", false);
        size4 = new JRadioButton ("16", true);

        panel1 = new JPanel();
        panel2 = new JPanel();
        panel3 = new JPanel();

        saying = new JLabel ("Say it with style!");
        saying.setFont (new Font ("Helvetica", Font.PLAIN, 36)); // we'll need this later

        ButtonGroup group = new ButtonGroup(); //use this code for the homework
        group.add (style1);
        group.add (style2);
        group.add (style3); 
        group.add (style4);

        style1.addActionListener (this);
        style2.addActionListener (this);
        style3.addActionListener (this);
        style4.addActionListener (this);

        ButtonGroup group2 = new ButtonGroup();
        group.add(size1);
        group.add(size2);
        group.add(size3);
        group.add(size4);

        size1.addActionListener (this);
        size2.addActionListener (this);
        size3.addActionListener (this);
        size4.addActionListener (this);

        setBackground (Color.red);
        setPreferredSize (new Dimension(500, 100));

        setLayout(new BorderLayout());
        add(panel1, BorderLayout.NORTH);
        add(panel2, BorderLayout.EAST);
        add(panel3, BorderLayout.WEST);

        //add(panel2, East);
        //add(panel3, West);

        panel1.add(saying);
        panel1.setBackground(Color.yellow);

        panel2.setLayout(new GridLayout());
        panel2.setBackground(Color.red);
        panel2.add(style1);
        panel2.add(style2);
        panel2.add(style3);
        panel2.add(style4);

        panel3.setLayout(new BoxLayout(panel3, BoxLayout.Y_AXIS));
        panel3.setBackground(Color.red);
        panel3.add(size1);
        panel3.add(size2);
        panel3.add(size3);
        panel3.add(size4);
    }
    //*****************************************************************
    //  Represents the listener for both check boxes and the radio boxes.
    //*****************************************************************
    public void actionPerformed(ActionEvent e) // this is our bread and butter, it is basically what we will be changing
    {
        Object source = e.getSource();

        if (style1.isSelected())
            font = "Arial";
        else
            if (style2.isSelected())
                font = "Times New Roman";
            else
                if (style3.isSelected())
                    font = "Verdana";
                else
                    if (style4.isSelected())
                        font = "Thonburi";
        saying.setFont(new Font (font, style, 36));
    }
    public static void main (String[] args)
    {
        JFrame frame = new JFrame ("Layouts");
        frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

        Layouts panel = new Layouts();
        frame.getContentPane().add(panel);

        frame.pack();
        frame.setVisible(true);
    }
}

Answer 1

You don’t have to hard code style1-4 into the listener. You see how you got the source of the action, but you never used it? That source is the radio button object that fired this event. You can just get the label on the radio button for the value. And then just set the font according the label value of the radio button that just fired the event. Also you might want to split this off into two eventhandlers, one for each set of radio buttons. Makes it easier to read and easier to discern which set is being clicked.