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Thread: showInputDialog method

  1. #1
    Java kindergarten chronoz13's Avatar
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    Default showInputDialog method

    how am i suppose to make a choice for the cancel_option of
    showInputDialog method?


    lets put in this way
    in the showConfirmDialog like this

            confirmation = JOptionPane.showConfirmDialog(null, "You Want To Procced Or Not?", "Confirmation", JOptionPane.YES_NO_CANCEL_OPTION);
     
            switch (confirmation) {
     
                case JOptionPane.YES_OPTION:
     
                    JOptionPane.showMessageDialog(null, "YES!");
                    break;
     
                case JOptionPane.NO_OPTION:
     
                    JOptionPane.showMessageDialog(null, "NO!");
                    break;
     
                case JOptionPane.CANCEL_OPTION:
     
                    JOptionPane.showMessageDialog(null, "CANCEL!");
                    break;


    how about in showInputDialog?
            String widthInput = JOptionPane.showInputDialog(null, "Between 100 And 500 Pixels Inclusive: ",
                                                            "Width Of The Shape", JOptionPane.WARNING_MESSAGE);

    i cant make a switch Statement for a String value...
    so in case i press the cancel button
    theres an output that will display..


    everytime i press the cancel button , the compiler shows me this

    [COLOR="Red"]Exception in thread "main" java.lang.NumberFormatException: null
            at java.lang.Integer.parseInt(Integer.java:417)
            at java.lang.Integer.parseInt(Integer.java:499)
            at preDefinedClassesApplications.Ch5DrawShape.inputDimension(Ch5DrawShape.java:216)
            at preDefinedClassesApplications.Ch5DrawShape.getShape(Ch5DrawShape.java:47)
            at preDefinedClassesApplications.Ch5DrawShape.start(Ch5DrawShape.java:34)
            at preDefinedClassesApplications.Ch5DrawShape.main(Ch5DrawShape.java:274)
    [/COLOR]


  2. #2
    Java kindergarten chronoz13's Avatar
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    Default Re: showInputDialog method

    never mind .. i solved it this way..
    i saw a sample of inputDialog in the internet

    and i analyze how does it happen to be fine (not displaying an exception) , when a user press the cancel button

    heres the code that i made from the one that i got in the net... this might help others regarding with inputDialog

        public static void main(String[] args) {
     
            String x = (String) JOptionPane.showInputDialog(null, "Press The Cancel!");
     
            if (x == null) {
     
                System.out.println("Theres No NumberFormatException Anymore!");
            }       
        }
    }


    now my question is about the code that ive got


    heres the code that ive got in the internet about inputDialog

    public class ComboBoxShowInputDialog
    {
      public static final String[] pizzas = { "Cheese", "Pepperoni", "Sausage", "Veggie",
                                              "Keso", "Tuna", "Baboy"};
     
      public static void main(String[] args)
      {
        JFrame frame = new JFrame("Input Dialog Example 3");
     
        String favoritePizza = (String) JOptionPane.showInputDialog(frame, "What is your favorite pizza?", "Favorite Pizza", JOptionPane.QUESTION_MESSAGE, null, pizzas, null);
     
        // favoritePizza will be null if the user clicks Cancel
        System.out.printf("Favorite pizza is %s.\n", favoritePizza);
        System.exit(0);
      }
     
    }

    im using the System class together with .print() .prntln() methods..
    but i didnt knew theres another print method signatured as
     printf()

    whats the purpose of this method? in my opinion.. this one accepts and displays objects.. (thats the only thing i notice about it),
    Last edited by chronoz13; November 22nd, 2009 at 06:07 AM.

  3. #3
    Super Moderator helloworld922's Avatar
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    Default Re: showInputDialog method

    printf is a "remenant" that's quite useful from the C/C++ languages (actually, a lot of programming languages has it). It basically stands for "print formatted". You can format how you want the output displayed.

    ex: say you want to display a double with 2 decimal places:

    System.out.printf("%.2f",123.456789);

    The reason it's in these other languages is because they don't automatically concatenate strings together like in Java:

    System.out.print("The answer is " + 123.456789 + " meters");

    printf("The answer is %f meters", 123.456789);

    Java also has a number formatting class if you don't want to use the printf method and want to format it in different ways.