Thread: JOptionPane help

Okay so my instructor just told us we needed to use a GUI via JOptionPane with our program. So that we may turn out programs in as executable jar files. However, I have never used it and im kind of new at this stuff so I need some help. Here is my problem and code:

package waitingroomlinkedlist;
import java.util.Scanner;
import javax.swing.JOptionPane;
 
public class WaitingRoomLinkedList {
 
    public static void main(String args[]) {
        boolean done = false;
        String inputFirst;
        String inputLast;
 
        String[] choices = {"First Name", "Last Name", "Quit"};
        while (!done) {
            int choice = JOptionPane.showOptionDialog(
                    null,
                    "Personal Information:",
                    "Register",
                    JOptionPane.YES_NO_CANCEL_OPTION,
                    JOptionPane.QUESTION_MESSAGE,
                    null,
                    choices,
                    choices[0]);
 
            switch (choice){
                case 0:
                    inputFirst = JOptionPane.showInputDialog( "Enter First Name");
                    break;
 
                case 1:
                    inputLast = JOptionPane.showInputDialog("Enter Last Name");
                    break;
 
                case 2:
                    done = true;
                    JOptionPane.showMessageDialog(
                        null,
                        "...quitting!",
                         "",
                         JOptionPane.ERROR_MESSAGE);
                    break;
            }
        }
        Person p1 = new Person(inputFirst, inputLast);
    }
}

Now for some reason I am getting an error when trying to create a new instance of the Person class and pass inputFirst and inputLast. Its telling me that I have not initialized inputFirst or Last. When I allow it to initialize it sets inputFirst = null; and so forth with inputLast. Any idea what's going on here? All I want to do is pass the two Strings to my constructor in my Person class.

Oh I see now thank you. So I have another question. Is it possible to print in a JOptionsPane window?

JOptionPane.ERROR_MESSAGE
JOptionPane.INFORMATION_MESSAGE
JOptionPane.WARNING_MESSAGE
JOptionPane.QUESTION_MESSAGE
JOptionPane.PLAIN_MESSAGE

These are the only thing I could find however I realize how to print a message like this. What im trying to figure out is how to say write:

JOptionPane.showMessageDialog(null, p1.printName(), JOptionPane.PLAIN_MESSAGE)

The problem I am encountering is how to get p1 to be a recognized variable. I create an instance of the Person class before I create the GUI then I can't pass info from the GUI to the person class. Also, randomly creating an instance of the person class inside one of the case's doesn't seem like the way to go about it. I want it to act like the Quit button instead rather than have it print "quitting..." I want it to print First name Last name and a number(ticket #).

To answer your question no the print method is just something I made in order to test if I could call my methods inside the JOptionPane. I think this might be what you meant by define it in scope tell me if im wrong:

case 2: 
Person p1 = new Person(inputFirst, inputLast); 
JOptionPane.showMessageDialog(null, p1.printName, JOptionPane.PLAIN_MESSAGE);

Says that void type is not allowed here any way around that?

Okay so I tried changing my printName() method so that it would return fName and lName. However, now in the person class the error is similar in that a String cannot be converted to void. Here is the Person class as is:

public class Person{
private String fName;
private String lName;
public int counter = 1;
 
public Person(String fName, String lName){
this.fName = fName;
this.lName = lName;
counter++;
}
 
public printName(){
return (fName + lName);
}

I am really kind of lost at this point. What I want is when someone puts in there first name last name. Then I want to give them a number and store (either the number or the names.. or both) into the queue so that when someone hits the next button it dequeues first name, last name and the number and then prints that info in the JOptionsPane. This is the most complicated program I have undertaken so far so please bear with me.

I figured out the problem being reported in the Person class. I defined the method as a string to fix it. Here is the error in the main class:

"error: no suitable method found for showMessageDialog(<null>,String,int)
JOptionPane.showMessageDialog(null, p1.printName(), JOptionPane.PLAIN_MESSAGE);
method JOptionPane.showMessageDialog(Component,Object) is not applicable
(actual and formal argument lists differ in length)
method JOptionPane.showMessageDialog(Component,Object,Str ing,int) is not applicable
(actual and formal argument lists differ in length)
method JOptionPane.showMessageDialog(Component,Object,Str ing,int,Icon) is not applicable
(actual and formal argument lists differ in length)
1 error"

I think maybe I should convert the string to an object or something.. not sure.

Ha your a genious I knew it. Okay so now I think I have found a way to print the ticket number as well. It writes the message in the upper portion of the dialog window so in the lower portion could be the ticket number. Thanks! I will come back if I get stuck again.

--- Update ---

Now the somewhat mind boggling part. How can I make my program create a new person every time a first and last name is entered, so that my program handles multiple people? I am starting to think I shouldn't have tried going the route you have been helping me with... I read that I can do something like create a new (method?) inside my main method that will handle the inputs like this:

private static void processInputString(String inputFirst);

then what I do inside the case is say:

processInputString(inputFirst)

. Doing it this way might allow me to operate on each input, however I am not sure if this is the right way to go about it either because then I might have trouble with printing again... Any suggestions?

Also, why might my program compile/build successfully but when I choose to run the program it pops up a message saying error were found? The program still works too.

Post error messages that you want help with.

As for your design question, try doing it "this way" as you suggest and see what happens. If you don't like the results, then change it. If you're not sure how, come back and explain what you're trying to do but can't figure out how to do.

Okay so "this" didn't work out. I found some info online on a different method of using JOptionPane. I think I am on the right track but I am running into some problems with data types not being compatible. Here is the full program as is:

package tester;
 
import java.util.NoSuchElementException;
import javax.swing.JOptionPane;
 
public class Tester{
    public static void main(String args[])
    {
       String firstName; 
       String lastName;
       int i = 1;
       Person personReference;
       boolean done = false;
 
       LinkedList personQueue = new LinkedList();
 
       String[] choices = {"Emter Name", "Next", "empty?", "quit"};
       while (!done) {
            int choice = JOptionPane.showOptionDialog(
                    null, 
                    "Click a choice",
                    "Stack Operations Menu",
                    JOptionPane.YES_NO_CANCEL_OPTION,
                    JOptionPane.QUESTION_MESSAGE, 
                    null,
                    choices,
                    choices[0]);
            try{
                switch (choice){
                case 0:
                            firstName = JOptionPane.showInputDialog("Enter first name");
                            lastName = JOptionPane.showInputDialog("Enter last name");
                            personReference = new Person(firstName, lastName, i);
                            LinkedList.push(personReference);
                        break;                   
                case 1:
                        if (LinkedList.isEmpty()){
                            JOptionPane.showMessageDialog(
                                null,
                                "Cannot pop; stack is empty!");
                        }
                        else{
                            personReference = LinkedList.pop();
                            JOptionPane.showMessageDialog(
                                null,
                                "The top dog on the stack was "
                                    + personReference.getName() 
                                    + " of breed "
                                    + personReference.getTicketNumber() + ".");
                        }
                        break;
 
                case 2:
                        if (LinkedList.isEmpty()){
                            JOptionPane.showMessageDialog(
                                null,
                                "The stack is empty!");
                        }
                        else {
                            JOptionPane.showMessageDialog(
                                null,
                                "The stack is not empty!");
                        }
                        break;
 
                case 3: 
                        done = true;
                        break;
                default: 
                        JOptionPane.showMessageDialog(
                                null,
                                "Invalid selection; try again!");
                } //end switch
            } // end try
            catch (NoSuchElementException e){
                JOptionPane.showMessageDialog(
                        null,
                        "The Stack is Empty",
                        "",
                        JOptionPane.ERROR_MESSAGE);
 
            } // end catch
 
       } // end while
    }
}

package tester;
 
public class LinkedList {
 
    public static ListNode firstLink;
 
 
    LinkedList()
    {
        firstLink = null;
    }
 
    public static boolean isEmpty()
    {
        return(firstLink == null);
    }
 
    public static push(Person parentheses)
    {
        firstLink = new ListNode(parentheses, firstLink);
 
   public static pop()
    {
        firstLink = firstLink.next;
        return(firstLink);
    }
 
 
}

package tester;
 
class ListNode
{
    public ListNode(Person parentheses)
    {
        this(parentheses, null);
    }
 
    public ListNode(Person parentheses, ListNode n)
    {
        element = parentheses;
        next = n;
    }
    public Object element;
    public ListNode next;
}

package tester;
 
public class Person {
 
    private final String fName;
    private final String lName;
    public int counter;
 
    public Person(String fName, String lName, int inCounter)
    {
        this.fName = fName;
        this.lName = lName;
        this.counter = inCounter;
        counter++;
    }
 
    public String getName()
    {
        return (fName + lName);
    }
 
    public int getTicketNumber()
    {
        return(counter);
    }
 
}

The problem atm is with the pop method. In the LinkedList class the error reports this when I highlight the first line for the method: "invalid method declaration; return type required" Followed by: "Incompatible types: unexpected return value" when I highlight the return statement. This doesn't make sense to me on two fronts a) there is a return being made and b) the method is not void

Then in Tester when I try to call

personReference = LinkedList.pop();

on line 43 the error says this when I highlight that line: "void cannot be converted to person". Now im not sure what's void personReference?

Yes sorry here is the full error:

"ant -f C:\\Users\\rob\\Documents\\NetBeansProjects\\Teste r -Dnb.internal.action.name=rebuild clean jar
init:
deps-clean:
Updating property file: C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld\built-clean.properties
Deleting directory C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld
clean:
init:
deps-jar:
Created dir: C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld
Updating property file: C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld\built-jar.properties
Created dir: C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld\classes
Created dir: C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld\empty
Created dir: C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld\generated-sources\ap-source-output
Compiling 4 source files to C:\Users\rob\Documents\NetBeansProjects\Tester\bui ld\classes
C:\Users\rob\Documents\NetBeansProjects\Tester\src \tester\LinkedList.java:23: error: invalid method declaration; return type required
public static pop()
1 error
C:\Users\rob\Documents\NetBeansProjects\Tester\nbp roject\build-impl.xml:923: The following error occurred while executing this line:
C:\Users\rob\Documents\NetBeansProjects\Tester\nbp roject\build-impl.xml:263: Compile failed; see the compiler error output for details.
BUILD FAILED (total time: 1 second)"

I tried changing the pop method to type Person but then it talks about not being able to convert a node to a person.

Ah ic so I changed the method type to ListNode but now I can't use the method since its of type Node and Node cannot be converted to Person. Is there any way around this or am I not going to be able to call my methods on an instance of Person? Seems odd since push returns.

Well when I push a person and set it equal to firstLink doesn't that make firstLink a reference to a person object?

firstLink = new ListNode(person, firstLink);

Okay so now I am thinking I shouldn't be trying to return anything at all. Which puts me back at square one were void type cannot be converted to Person.