LAB ACTIVITY 3F

Learning Outcomes

  By the end of this lab, students should be able to :

• • Write Java programs using Event Handling

  • Write Java programs using Event Handling with GUI Components

Hardware/ Software : Personal Computer, Java Development Kit version X.x.x., NetBeans IDE 12.0

LAB ACTIVITY 3F

Activity Outcome: Student know how to create event handling program for radio button.

CREATE New Project name as TestRadioButton

i. Type the following code:

package testradiobutton;

import java.awt.*;

import javax.swing.*;

class TestRadioButton extends JFrame {

private ButtonGroup pilihan = new ButtonGroup();

private JRadioButton pilihan1 = new JRadioButton();

private JRadioButton pilihan2 = new JRadioButton("Medium Pizza");

private JRadioButton pilihan3 = new JRadioButton("Small  Pizza",false);

    TestRadioButton(){

        setTitle("Test RadioButton"); 

        setLayout(new FlowLayout());

        pilihan1.setText("Large Pizza");

        pilihan1.setSelected(false);

        pilihan2.setSelected(false);

        pilihan.add (pilihan1);

        pilihan.add (pilihan2);

        pilihan.add (pilihan3);

        add (pilihan1);

        add (pilihan2);

        add (pilihan3);

        setSize(400,100);

        setVisible(true);

    }

    public static void main (String[] arg) 

    {

            TestRadioButton pilih =new TestRadioButton();

    }

}

ii. Declaration of the event handler class

a) Add package java.awt.event.*;

b) implements ItemListener

example image:

iii. Registers an instance of the event handler class 

pilihan1.addItemListener(this);

pilihan2.addItemListener(this);

pilihan3.addItemListener(this);

example image:

iv. Implements the methods in the listener interface.

  public void itemStateChanged(ItemEvent e){

        if (pilihan1.isSelected())

        JOptionPane.showMessageDialog(null,"YOU HAVE CHOOSE LARGE   PIZZA" 

                                  ,"PIZZA",JOptionPane.INFORMATION_MESSAGE);

        else if (pilihan2.isSelected())

        JOptionPane.showMessageDialog(null,"YOU HAVE CHOOSE MEDIUM PIZZA" 

                                  ,"PIZZA",JOptionPane.INFORMATION_MESSAGE);

        else if (pilihan3.isSelected())

        JOptionPane.showMessageDialog(null,"YOU HAVE CHOOSE SMALL PIZZA", 

                                   "PIZZA",JOptionPane.INFORMATION_MESSAGE);

    }

example image:

FULL CODE & EXAMPLE GUI OUTPUT :

package testradiobutton;

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

class TestRadioButton extends JFrame implements ItemListener{

private ButtonGroup pilihan = new ButtonGroup();

private JRadioButton pilihan1 = new JRadioButton();

private JRadioButton pilihan2 = new JRadioButton("Medium Pizza");

private JRadioButton pilihan3 = new JRadioButton("Small  Pizza",false);

    TestRadioButton(){

        setTitle("Test RadioButton"); 

        setLayout(new FlowLayout());

        pilihan1.setText("Large Pizza");

        pilihan1.setSelected(false);

        pilihan2.setSelected(false);

        pilihan.add (pilihan1);

        pilihan.add (pilihan2);

        pilihan.add (pilihan3);

        pilihan1.addItemListener(this);

        pilihan2.addItemListener(this);

        pilihan3.addItemListener(this);

        add (pilihan1);

        add (pilihan2);

        add (pilihan3);

        setSize(400,100);

        setVisible(true);

    }

    public static void main (String[] arg) 

    {

            TestRadioButton pilih =new TestRadioButton();

    }

   public void itemStateChanged(ItemEvent e){

        if (e.getSource()==pilihan1)   

                        valLarge=pilihan1.isSelected()? pilihan1.getText() +"\n":"";

        if (e.getSource()==pilihan2)

                        valRegular=pilihan2.isSelected()? pilihan2.getText() +"\n":"";

        if (e.getSource()==pilihan3)

                        valSmall=pilihan3.isSelected()? pilihan3.getText() +"\n":"";

        JOptionPane.showMessageDialog(null,s+valLarge+valRegular+valSmall,

        "PIZZA",JOptionPane.INFORMATION_MESSAGE);

    }

}

OUTPUT :   (Click on RadioButton to show process)