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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 : 

1. ERROR_MESSAGE
2. WARNING_MESSAGE
3. QUESTION_MESSAGE
4. INFORMATION_MESSAGE

Methods Used : 

1. 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.
2. 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.
3. setVisible(…): method is used to set the Visibility status of JFrame. 
   1. setVisible(true) will set JFrame visible to user.
   2. setVisible(false) will set JFrame not visible to user.
4. 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.
5. 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 :

Output : 

Output : 
 

Output : 

Output : 

Introduction to JOptionPane in Java

The JOptionPane is a class that is used to provide standard dialog boxes. It is a part of Java Swing which is used for creating window-based applications. JOptionPane is a component from Java Swing and it deals with dialog boxes especially. The dialog boxes can be of any type such as confirm dialog box, message dialog box or input dialog box. These dialog boxes can be used to display information to the user or to get input from the user.

Syntax:

public class JOptionPane extends JComponent implements Accessible

JComponent is a base class for Swing Components and Accessible is the main interface for the accessibility package. They both provide a standard mechanism that is required to support swing architecture.

JOptionPane Constructors

Below are the constructors as follows:

• JOptionPane(): It creates an instance of JOptionPane with a default text message.
• JOptionPane(Object message, int messageType): It creates an object of JOptionPane which will display a message with specified message type and default options delivered by User Interface.
• JOptionPane(Object message): It creates an object of JOptionPane which will display a message with plain-message message type and default options delivered by User Interface.
• JOptionPane(Object message, int messageType, int option type): It creates an instance of JOptionPane which will display a message with specified message type and options as well.
• JOptionPane(Object message, int messageType, int optionType, Icon icon): Display a message with specified message type, option type and icon as well.

Methods of JOptionPane in Java

While there is a large number of methods in the JOptionPane class, they all fit in the format of showXxxDialog as below:

• showInputDialog: Prompt user for some input.
• showMessageDialog: Shows the dialog box with a message to the user.
• show confirm dialog: Asks user a confirming question, like yes/no/cancel.
• showOptionDialog: The combination of the above three.

All of these methods also come in showInternalXXX flavor, which will use an internal frame to hold the dialog box. Below are the commonly used methods in JOptionPane class:

Almost all the methods from the JOptionPane class are static methods. Mostly we will access them directly without creating an instance of JOptionPane.

Examples of JOptionpane in Java

Below are the examples follow:

1. showMessageDialog()

Code:

simple dialog box with only message:

import javax.swing.JOptionPane;
public class Main extends JOptionPane
{
public static void main (String[] args)
{
JOptionPane.showMessageDialog( null, "Hello World..!" );
}
}

Here, the parent component is passed as null which means that there will be no parent for the dialog box and String argument is text message which will be shown on dialog box as information to the user.

Output:

2. showMessageDialog()

Same as example 1 but with additional title and message type as the argument:

Code:

import javax.swing.JOptionPane;
public class JOptionPaneExample
{
public static void main( String[] args )
{
JOptionPane.showMessageDialog( null, "Something Went Wrong.." , "Error as Title",
JOptionPane.ERROR_MESSAGE );
}
}

Output:

3. showInputDialog()

Take input from the user and display it on a dialog box.

Code:

import javax.swing.JOptionPane;
public class JOptionPaneExample extends JOptionPane
{
public static void main( String[] args )
{
String name = JOptionPane.showInputDialog( "Provide User Name:" );
JOptionPane.showMessageDialog(null, name);
}
}

Output:

4. showConfirmDialog()

Code:

package swing.demo.dialogBox;
import javax.swing.JOptionPane;
public class JOptionPaneExample
{
public static void main( String[] args )
{
int input = JOptionPane.showConfirmDialog(null, "Are you Sure?");
// 0=yes, 1=no, 2=cancel
System.out.println(input);
}
}

Output:

Conclusion

In windows-based applications, Java Swing makes it very easy to develop them and it is a very powerful API. JOptionPane being a part of it simplifies creating dialog boxes in an easy manner. It provides standard dialog boxes such as the input dialog box, confirms dialog box and message dialog box. We can create our own custom dialog boxes as well. Since JOptionPane provides standard dialog boxes, it is very useful.

Recommended Articles

This is a guide to JOptionPane in Java. Here we discuss the constructor, methods, and examples of JOptionPane in java. You can also go through our other related articles to learn more –

1. JTextField in Java
2. JScrollPane in Java
3. JDialog in Java
4. JComboBox in Java

JOptionPane enables you to create and customize various kinds of dialogs. With JOptionPane the dialogs can have customized dialog layout, icons, dialog title, dialog text and button text. In addition, JOptionPane allows you to customize the displaying component and its position where on the screen dialog display.

To create simple modal dialogs, you use static methods of JOptionPane showAbcDialog() for instanceshowMessageDialog(). If a dialog has to be in an internal frame you can use showInteralAbcDialog() for example showInternalMessageDialog(). In order to create modeless dialog you need to create new instance of JOptionPane and add it to a JDialog instance. And then you call method setVisible(true)  of the JDialog’s instance to make it visible on screen.

JOptionPane provides you with two useful static methods such as showMessageDialog() and showOptionDialog(). The showMessageDialog() method shows a very simple dialog with one button while showOptionDialog() method displays a highly customized dialogs with different buttons texts. Besides these methods, JOptionPane provides showConfirmDialog() method to ask users to confirm an action and showInputDialog() to get simple input from the users.

Example of Using Method showMessageDialog of JOptionPane

In this example, we use showMessageDialog() method of JOptionPane to show various simple dialog with one button and different icons which represent different message types such as information, warning, error and question message. When you click on each radio button, it will display corresponding message type.

package joptionpanedemo1;

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

public class Main {

    public static void main(String[] args) {
        final JFrame frame = new JFrame("JOptionPane Demo");

        // implement ItemListener interface
        class MyItemListener implements ItemListener {

            public void itemStateChanged(ItemEvent ev) {
                boolean selected = (ev.getStateChange() == ItemEvent.SELECTED);
                AbstractButton button = (AbstractButton) ev.getItemSelectable();
                String command = button.getActionCommand();
                if (selected) {
                    int messageType = -1;
                    String message = "";
                    if (command.equals("INFORMATION")) {
                        messageType = JOptionPane.INFORMATION_MESSAGE;
                        message = "Information Message";
                    } else if (command.equals("WARNING")) {
                        messageType = JOptionPane.WARNING_MESSAGE;
                        message = "Warning Message";
                    } else if (command.equals("ERROR")) {
                        messageType = JOptionPane.ERROR_MESSAGE;
                        message = "Error Message";
                    } else if (command.equals("QUESTION")) {
                        messageType = JOptionPane.QUESTION_MESSAGE;
                        message = "Question Message";
                    }
                    // show message
                    JOptionPane.showMessageDialog(frame,
                            message,
                            "Message Dialog",
                            messageType);
                }
            }
        }

        JRadioButton r1 = new JRadioButton("Information Message");
        r1.setActionCommand("INFORMATION");

        JRadioButton r2 = new JRadioButton("Warning Message");
        r2.setActionCommand("WARNING");

        JRadioButton r3 = new JRadioButton("Error Message");
        r3.setActionCommand("ERROR");

        JRadioButton r4 = new JRadioButton("Question Message");
        r4.setActionCommand("QUESTION");

        // add event handler
        MyItemListener myItemListener = new MyItemListener();
        r1.addItemListener(myItemListener);
        r2.addItemListener(myItemListener);
        r3.addItemListener(myItemListener);
        r4.addItemListener(myItemListener);

        // add radio buttons to a ButtonGroup
        final ButtonGroup group = new ButtonGroup();
        group.add(r1);
        group.add(r2);
        group.add(r3);
        group.add(r4);

        // Frame setting
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);
        Container cont = frame.getContentPane();

        cont.setLayout(new GridLayout(0, 1));
        cont.add(new JLabel("Please choose the message type:"));
        cont.add(r1);
        cont.add(r2);
        cont.add(r3);
        cont.add(r4);

        frame.setVisible(true);
    }
}
Code language: JavaScript (javascript)

Example of Using Method showOptionDialog to Create Dialogs

In this example, we use showOptionDialog method to show question dialog with as yes/no and yes/no/cancel options.

package joptionpanedemo2;

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

public class Main {

    public static void main(String[] args) {
        final JFrame frame = new JFrame("JOptionPane Demo");

        // implement ItemListener interface
        class MyItemListener implements ItemListener {
            public void itemStateChanged(ItemEvent ev) {
                boolean selected = (ev.getStateChange() == ItemEvent.SELECTED);
                AbstractButton button = (AbstractButton) ev.getItemSelectable();
                String command = button.getActionCommand();
                if (selected) {
                    int optionType = -1;

                    if (command.equals("YES_NO_OPTION")) {
                        optionType = JOptionPane.YES_NO_OPTION;
                    } else if (command.equals("YES_NO_CANCEL_OPTION")) {
                        optionType = JOptionPane.YES_NO_CANCEL_OPTION;
                    }

                    JOptionPane.showOptionDialog(frame,
                            "Are you sure to confirm the action you've made?",
                            "JOptionPane Demo",
                            optionType,
                            JOptionPane.INFORMATION_MESSAGE, // icon
                            null,
                            null,
                            null);
                }
            }
        }

        JRadioButton r1 = new JRadioButton("Yes / No Options");
        r1.setActionCommand("YES_NO_OPTION");

        JRadioButton r2 = new JRadioButton("Yes / No / Cancel Options");
        r2.setActionCommand("YES_NO_CANCEL_OPTION");

        // add event handlers
        MyItemListener myItemListener = new MyItemListener();
        r1.addItemListener(myItemListener);
        r2.addItemListener(myItemListener);

        // add radio buttons to a ButtonGroup
        final ButtonGroup group = new ButtonGroup();
        group.add(r1);
        group.add(r2);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);
        Container cont = frame.getContentPane();
        cont.setLayout(new GridLayout(0, 1));
        cont.add(new JLabel("Please choose the options type:"));
        cont.add(r1);
        cont.add(r2);

        frame.setVisible(true);
    }
}
Code language: JavaScript (javascript)