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

Code :

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        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?

Code :

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        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

Code :

---

[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]

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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

Code :

---

    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

Code :

---

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);
  }
 
}

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

Code :

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 printf()

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whats the purpose of this method? in my opinion.. this one accepts and displays objects.. (thats the only thing i notice about it),

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:

Code :

---

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:

Code :

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

---

Code :

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

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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.