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PotatoScript edited this page Mar 30, 2025 · 1 revision

📝 JCheckBox and RadioButton in Java Swing 🎯

🎯 What is JCheckBox?

JCheckBox is a component in Java Swing that allows users to select one or more options from a list. It provides a checkbox that can be checked or unchecked, commonly used in forms or settings to represent multiple options.

✅ Features of JCheckBox:

  • Multiple selection: Users can select as many checkboxes as they want.
  • State management: The checkbox can be in a checked or unchecked state.

📚 Step 1: Creating a Basic JCheckBox

📝 Example: Creating JCheckBox 

import javax.swing.*;

public class JCheckBoxExample {
    public static void main(String[] args) {
        // Create JFrame
        JFrame frame = new JFrame("JCheckBox Example");

        // Create JCheckBoxes
        JCheckBox option1 = new JCheckBox("Option 1");
        JCheckBox option2 = new JCheckBox("Option 2");

        // Set layout and add components
        frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
        frame.add(option1);
        frame.add(option2);

        // Set frame properties
        frame.setSize(300, 200);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

🎨 Explanation

✅ JCheckBox option1 = new JCheckBox("Option 1");

  • Creates a checkbox labeled Option 1.

✅ frame.add(option1);

  • Adds the checkbox to the frame.

👩‍🎨 Output: 

+-------------------------------+
| [ ] Option 1                   |
| [ ] Option 2                   |
+-------------------------------+

🎯 Step 2: Handling JCheckBox State Change

To respond to checkbox state changes (checked or unchecked), you can add an ActionListener or ItemListener.

📝 Example: Handling JCheckBox Selection 

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

public class JCheckBoxSelection {
    public static void main(String[] args) {
        // Create JFrame
        JFrame frame = new JFrame("JCheckBox Selection");

        // Create JCheckBoxes
        JCheckBox option1 = new JCheckBox("Option 1");
        JCheckBox option2 = new JCheckBox("Option 2");

        // Create JLabel to display selected options
        JLabel label = new JLabel("Selected Options: None");

        // Add ItemListener to update label when state changes
        option1.addItemListener(e -> updateLabel(option1, option2, label));
        option2.addItemListener(e -> updateLabel(option1, option2, label));

        // Set layout and add components
        frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
        frame.add(option1);
        frame.add(option2);
        frame.add(label);

        // Set frame properties
        frame.setSize(300, 200);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    // Method to update label based on selected options
    private static void updateLabel(JCheckBox option1, JCheckBox option2, JLabel label) {
        String selected = "Selected Options: ";
        if (option1.isSelected()) {
            selected += "Option 1 ";
        }
        if (option2.isSelected()) {
            selected += "Option 2";
        }
        label.setText(selected.isEmpty() ? "Selected Options: None" : selected);
    }
}

🎨 Explanation

✅ option1.addItemListener(e -> updateLabel(option1, option2, label));

  • When the checkbox is checked or unchecked, the updateLabel() method is called to update the label based on the selected options.

👩‍🎨 Output: 

+-------------------------------+
| [ ] Option 1                   |
| [ ] Option 2                   |
| Selected Options: None         |
+-------------------------------+

(When Option 1 is checked):
+-------------------------------+
| [x] Option 1                   |
| [ ] Option 2                   |
| Selected Options: Option 1     |
+-------------------------------+

🎯 What is a RadioButton (JRadioButton)?

JRadioButton is a component used for selecting one option from a group of choices. Unlike checkboxes, only one radio button in a group can be selected at a time. Radio buttons are often used in forms when you need to allow the user to select only one option from a set.

✅ Features of JRadioButton:

  • Single selection: Only one radio button can be selected at a time in a group.
  • Button grouping: Radio buttons must be grouped using a ButtonGroup.

📚 Step 3: Creating a Basic JRadioButton

📝 Example: Creating JRadioButton 

import javax.swing.*;
import javax.swing.ButtonGroup;

public class JRadioButtonExample {
    public static void main(String[] args) {
        // Create JFrame
        JFrame frame = new JFrame("JRadioButton Example");

        // Create JRadioButtons
        JRadioButton option1 = new JRadioButton("Option 1");
        JRadioButton option2 = new JRadioButton("Option 2");
        JRadioButton option3 = new JRadioButton("Option 3");

        // Group radio buttons
        ButtonGroup group = new ButtonGroup();
        group.add(option1);
        group.add(option2);
        group.add(option3);

        // Set layout and add components
        frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
        frame.add(option1);
        frame.add(option2);
        frame.add(option3);

        // Set frame properties
        frame.setSize(300, 200);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

🎨 Explanation

✅ ButtonGroup group = new ButtonGroup();

  • Groups the radio buttons together so only one can be selected.

✅ group.add(option1);

  • Adds the radio button to the group.

👩‍🎨 Output: 

+-------------------------------+
| ( ) Option 1                  |
| ( ) Option 2                  |
| ( ) Option 3                  |
+-------------------------------+

🎯 Step 4: Handling JRadioButton Selection

To handle the selection of radio buttons, you can add an ActionListener.

📝 Example: Handling JRadioButton Selection 

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

public class JRadioButtonSelection {
    public static void main(String[] args) {
        // Create JFrame
        JFrame frame = new JFrame("JRadioButton Selection");

        // Create JRadioButtons
        JRadioButton option1 = new JRadioButton("Option 1");
        JRadioButton option2 = new JRadioButton("Option 2");
        JRadioButton option3 = new JRadioButton("Option 3");

        // Group radio buttons
        ButtonGroup group = new ButtonGroup();
        group.add(option1);
        group.add(option2);
        group.add(option3);

        // JLabel to display selected option
        JLabel label = new JLabel("Selected Option: None");

        // Add ActionListener to radio buttons
        option1.addActionListener(e -> label.setText("Selected Option: Option 1"));
        option2.addActionListener(e -> label.setText("Selected Option: Option 2"));
        option3.addActionListener(e -> label.setText("Selected Option: Option 3"));

        // Set layout and add components
        frame.setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));
        frame.add(option1);
        frame.add(option2);
        frame.add(option3);
        frame.add(label);

        // Set frame properties
        frame.setSize(300, 200);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

🎨 Explanation

✅ option1.addActionListener(e -> label.setText("Selected Option: Option 1"));

  • When Option 1 is selected, it updates the label with the selected option.

👩‍🎨 Output: 

+-------------------------------+
| ( ) Option 1                  |
| ( ) Option 2                  |
| ( ) Option 3                  |
| Selected Option: None         |
+-------------------------------+

(When Option 1 is selected):
+-------------------------------+
| (x) Option 1                  |
| ( ) Option 2                  |
| ( ) Option 3                  |
| Selected Option: Option 1     |
+-------------------------------+
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