LAB ACTIVITY 3G

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 3G

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

CREATE New Project name as TestSlider

i. Type the following code:

package testslider;

import java.awt.*;

import javax.swing.*;

class TestSlider extends JFrame {

//initial frames per second

static final int FPS_MIN = 0;

static final int FPS_MAX = 100;

static final int FPS_INIT = 50;

JSlider slide = new JSlider(JSlider.HORIZONTAL, FPS_MIN,FPS_MAX,FPS_INIT);

JLabel stmt   = new JLabel();

TestSlider(){

    setTitle("Test List");

    setLayout(new FlowLayout());

    stmt.setForeground(Color.BLUE);

    slide.setFont(new Font("Tahoma",Font.BOLD+Font.ITALIC,8));

    slide.setMajorTickSpacing(10);

    slide.setMinorTickSpacing(1);

    slide.setPaintTicks(true);

    slide.setPaintLabels(true);

    add(slide);

    add(stmt);

    setSize(300,200);

    setVisible(true);

}

    public static void main (String[] arg)

    {

            TestSlider scroll =new TestSlider();

    }

}

ii. Declaration of the event handler class

a) Add package javax.swing.event.*;  

b) implements ChangeListener

example image:

iii. Registers an instance of the event handler class 

slide.addChangeListener(this);

example image:

iv. Implements the methods in the listener interface.

  public void stateChanged(ChangeEvent e){

             int value;

             value = slide.getValue();

             stmt.setText("The value you have point is "+value);

        }

example image:

FULL CODE & EXAMPLE GUI OUTPUT :

package testslider;

import java.awt.*;

import javax.swing.*;

import javax.swing.event.*;

class TestSlider extends JFrame implements ChangeListener{

//initial frames per second

static final int FPS_MIN = 0;

static final int FPS_MAX = 100;

static final int FPS_INIT = 50;

JSlider slide = new JSlider(JSlider.HORIZONTAL, FPS_MIN,FPS_MAX,FPS_INIT);

JLabel stmt   = new JLabel();

TestSlider(){

    setTitle("Test List");

    setLayout(new FlowLayout());

    stmt.setForeground(Color.BLUE);

    slide.setFont(new Font("Tahoma",Font.BOLD+Font.ITALIC,8));

    slide.setMajorTickSpacing(10);

    slide.setMinorTickSpacing(1);

    slide.setPaintTicks(true);

    slide.setPaintLabels(true);

    add(slide);

    add(stmt);

   slide.addChangeListener(this);

    setSize(300,200);

    setVisible(true);

}

    public static void main (String[] arg)

    {

            TestSlider scroll =new TestSlider();

    }

   public void stateChanged(ChangeEvent e){

             int value;

             value = slide.getValue();

             stmt.setText("The value you have point is "+value);

   }

}

OUTPUT :   (Use mouse to drag pointer to show value at Label below)