CODEWITHSUNDEEP
javaswingjoptionpane
user3879568
user3879568

Reputation: 43

JOptionPane handling ok, cancel and x button

There is one problem I am facing with my JOptionPane if I don't key in anything,no matter what I press(the ok,cancel or the x button(the top right button in the JOptionPane)), it will prompt me until the I key in a positive value. but I only want the prompt to happen when i pressed ok.

If I click on cancel or the x button(the top right button in the JOptionPane), it will close the JOptionPane

How can I do this?

import javax.swing.JOptionPane;

public class OptionPane {
    public static void main(final String[] args) {
        int value = 0;
        boolean isPositive = false , isNumeric = true;
        do {
            try {
                value = Integer.parseInt(JOptionPane.showInputDialog(null,
                    "Enter value?", null));
            } catch (NumberFormatException e) {
                System.out.println("*** Please enter an integer ***");
                isNumeric = false;
            }

             if(isNumeric) {
                if(value <= 0) {
                    System.out.println("value cannot be 0 or negative");
                }

                else {
                    System.out.println("value is positive");
                    isPositive = true;
                }
            }
        }while(!isPositive);
    }
}

Upvotes: 4

Views: 24235

Answers (3)

bluevoxel
bluevoxel

Reputation: 5358

The basic approach for this can look like I've showed below:

Updated after @MadProgrammer comment.

import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class DemoJOption {
    public static void main(String args[]) {
        int n = JOptionPane.showOptionDialog(new JFrame(), "Message", 
        "Title", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE, 
        null, new Object[] {"Yes", "No"}, JOptionPane.YES_OPTION);

        if (n == JOptionPane.YES_OPTION) {
            System.out.println("Yes");
        } else if (n == JOptionPane.NO_OPTION) {
            System.out.println("No");
        } else if (n == JOptionPane.CLOSED_OPTION) {
            System.out.println("Closed by hitting the cross");
        }
    }
}

Upvotes: 7

Braj
Braj

Reputation: 46841

Simply move the code in try block and there is no need to use any flag just break the infinite loop once positive number is entered.

Sample code:

public static void main(final String[] args) {
    int value = 0;
    while (true) {
        try {
            value = Integer.parseInt(JOptionPane.showInputDialog(null, "Enter value?", null));

            if (value <= 0) {
                System.out.println("value cannot be 0 or negative");
            } else {
                System.out.println("value is positive");
                break;
            }
        } catch (NumberFormatException e) {
            System.out.println("*** Please enter an integer ***");
        }
    }
}

Upvotes: 1

Sanjeev
Sanjeev

Reputation: 9946

JoptionPane#showInputDialog returns user's input, or null meaning the user canceled the input.

So instead of directly parsing the return value. First check if it is null (User Cancelled) then do nothing if not null then parse for the integer value

Upvotes: 1

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