Message Dialogs in Java (GUI)
Message dialogs provide information to the user. Message dialogs are created with the JOptionPane.showMessageDialog() method.
We call the static showMessageDialog() method of the JOptionPane class to create a message dialog. We provide the dialog’s parent, message text, title, and message type. The message type is one of the following constants :
- ERROR_MESSAGE
- WARNING_MESSAGE
- QUESTION_MESSAGE
- INFORMATION_MESSAGE
Methods Used :
- setLayout(…): method helps us to set the layout of the container, often a JPanel, to say FlowLayout, BorderLayout, GridLayout, null layout, or whatever layout we want to add on container.
- setBounds(…): method is used to set the location and size of components like JButton, and is only useful if null layout is used in JFrame.
- setVisible(…): method is used to set the Visibility status of JFrame.
- setVisible(true) will set JFrame visible to user.
- setVisible(false) will set JFrame not visible to user.
- getSource(): An event object contains a reference to the component that generated the event. To extract that reference from the event object we use getSource() Method.
- add(): It is used to add components like JButton etc, to the container of JFrame.
Below is the implementation of above discussed method to show Message Dialogs :
Java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Demo extends JFrame implements ActionListener
{
JButton b1;
Demo()
{
this .setLayout( null );
b1 = new JButton( "Button 1" );
b1.setBounds( 130 , 05 , 100 , 50 );
this .add(b1);
b1.addActionListener( this );
}
public void actionPerformed(ActionEvent evt)
{
if (evt.getSource() == b1)
{
JOptionPane.showMessageDialog( this , "Enter a valid Number" ,
"ERROR" , JOptionPane.ERROR_MESSAGE);
}
}
}
class MessageDialogs1 {
public static void main(String args[])
{
Demo f = new Demo();
f.setBounds( 200 , 200 , 400 , 300 );
f.setResizable( false );
f.setVisible( true );
}
}
|
Output :
Java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Demo extends JFrame implements ActionListener
{
JButton b1;
Demo()
{
this .setLayout( null );
b1 = new JButton( "Button 2" );
b1.setBounds( 130 , 05 , 100 , 50 );
this .add(b1);
b1.addActionListener( this );
}
public void actionPerformed(ActionEvent evt)
{
if (evt.getSource() == b1) {
JOptionPane.showMessageDialog( this , "Enter a valid String" ,
"WARNING" , JOptionPane.WARNING_MESSAGE);
}
}
}
class MessageDialogs2 {
public static void main(String args[])
{
Demo f = new Demo();
f.setBounds( 200 , 200 , 400 , 300 );
f.setResizable( false );
f.setVisible( true );
}
}
|
Output :
Java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Demo extends JFrame implements ActionListener
{
JButton b1;
Demo()
{
this .setLayout( null );
b1 = new JButton( "Button 3" );
b1.setBounds( 130 , 05 , 100 , 50 );
this .add(b1);
b1.addActionListener( this );
}
public void actionPerformed(ActionEvent evt)
{
if (evt.getSource() == b1)
{
JOptionPane.showMessageDialog( this , "Do you want to quit" ,
"Question" , JOptionPane.QUESTION_MESSAGE);
}
}
}
class MessageDialogs3 {
public static void main(String args[])
{
Demo f = new Demo();
f.setBounds( 200 , 200 , 400 , 300 );
f.setResizable( false );
f.setVisible( true );
}
}
|
Output :
Java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Demo extends JFrame implements ActionListener
{
JButton b1;
Demo()
{
this .setLayout( null );
b1 = new JButton( "Button 4" );
b1.setBounds( 130 , 05 , 100 , 50 );
this .add(b1);
b1.addActionListener( this );
}
public void actionPerformed(ActionEvent evt)
{
if (evt.getSource() == b1)
{
JOptionPane.showMessageDialog( this , "You Pressed Button FOUR" ,
"INFORMATION" ,
JOptionPane.INFORMATION_MESSAGE);
}
}
}
class MessageDialogs4 {
public static void main(String args[])
{
Demo f = new Demo();
f.setBounds( 200 , 200 , 400 , 300 );
f.setResizable( false );
f.setVisible( true );
}
}
|
Output :
Last Updated :
26 Oct, 2021
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