JOptionPane.showOptionDialog

[Jacob Coddaire]

Hey guys. I'm having trouble understanding the concept of this command. I'm creating a small game. Here's what I need to do.
1) Have a user specify how many players (2-4)
2) Have the user create names, or custom strings, for each player
3) Sort the names in an array
4) Create a dialog box that throws up the names and allows the user to select which will go first. The selection process should be either a JButton or radio button style, and should include the custom name set by the user.

For the record, steps one through three are done. My instructor said that this method would be the best for displaying the information I needed.

Here is what I figure:

start= JOptionPane.showOptionDialog(null, "Which player will play first?", "Player Selection", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, playerArray, null);
// start is an int, declared in the field. playerArray is the array in which the players name's are stored.
		

[Janeice DelVecchio]

What are you having trouble understanding? The syntax?

[Jacob Coddaire]

For some reason, it keeps getting this error message.
Exception in thread "main" java.lang.NullPointerException
at javax.swing.plaf.basic.BasicOptionPaneUI.addButtonComponents(Unknown Source)
at javax.swing.plaf.basic.BasicOptionPaneUI.createButtonArea(Unknown Source)
at javax.swing.plaf.basic.BasicOptionPaneUI.installComponents(Unknown Source)
at javax.swing.plaf.basic.BasicOptionPaneUI.installUI(Unknown Source)
at javax.swing.JComponent.setUI(Unknown Source)
at javax.swing.JOptionPane.setUI(Unknown Source)
at javax.swing.JOptionPane.updateUI(Unknown Source)
at javax.swing.JOptionPane.<init>(Unknown Source)
at javax.swing.JOptionPane.showOptionDialog(Unknown Source)
at Input.main(Input.java:60)

Here's my full code.

/**
	 * Jacob A. Coddaire
	 * 1.11.11
	 * This program should ask the user for information and store that data in an array.
	 * 
	 * The variables from this list that need to be used in other parts of the program are as follows:
	 * Players					playerArray[i]
	 * Starting Player			start
	 * Board Size				size
	 * # of Connects to win		win
	 */
import javax.swing.JOptionPane;
	
public class Input {
	
	public static int start;
	private static String name, sizeSTR, winSTR, playerSTR;
	private static int player, size, win;
	private static int playerCOUNT=1;
	private static int sizeCOUNT=1;
	private static int winCOUNT=1;
	
	public static void main(String[] args) {
				
		String[] playerArray = new String[4];// array in which the names of the players are stored
		
		//prompts the user for the number of players and checks that it is a legit amount
		playerSTR = JOptionPane.showInputDialog("How many players?(2-4)");
		for (int i=0; i<playerCOUNT; i++)
		{
			try
			{
				player = Integer.parseInt(playerSTR);
				if (player>4 || player<2)
				{
					// create a loop that runs if (player>4 || player<2). This prevents the player from entering in strange numbers....
						do
						{
							playerSTR = JOptionPane.showInputDialog("Quit being stupid. How many players?(2-4)");
							player = Integer.parseInt(playerSTR);
						}
						while (player>4 || player<2);
				}
			}
			catch (NumberFormatException e)
			{
					playerSTR = JOptionPane.showInputDialog("Only numbers are permitted. How many players?(2-4)");
					playerCOUNT++;
			}
		}
		//prompts the user to input a name, and it doesn't exceed the amount of players.
		for (int i=0; i<player; i++)
			{
				name = JOptionPane.showInputDialog("Enter a name:");
				playerArray[i] = name;	
			}
		
		// prompts the user for the person who will go first... needs tweaking.
		//start = JOptionPane.showInputDialog("Which player will go first?");
		start= JOptionPane.showOptionDialog(null, "Which player will play first?", "Player Selection", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, playerArray, null);
		
		// prompts the user for board size. Checks the legit size.
		sizeSTR = JOptionPane.showInputDialog("Enter the board size (10-25)");
		for (int b=0; b<sizeCOUNT; b++)
		{
			try
			{
				size = Integer.parseInt(sizeSTR);
				if (size<10 || size>25)
				{
					do
					{
							sizeSTR = JOptionPane.showInputDialog("Incorrect value. Enter the board size(10-25)");
							size = Integer.parseInt(sizeSTR);
					}
					while (size<10 || size>25);
				}
			}
			catch(NumberFormatException e)
			{
				sizeSTR = JOptionPane.showInputDialog("Only numbers are permitted. Enter the board size(10-25)");
				sizeCOUNT++;
			}
		}

		// prompts the user for number of connects needed to win. Checks for a legit number.
		winSTR = JOptionPane.showInputDialog("Enter the number of connects needed to win (4-8)");
		for (int a=0; a<winCOUNT; a++)
		{
			try
			{
				win = Integer.parseInt(winSTR);
				if (win>8 || win<4)
				{
					do
					{
						winSTR = JOptionPane.showInputDialog("Incorrect value. Enter the number of connects needed to win (4-8)");
						win = Integer.parseInt(winSTR);
					}
					while (win>8 || win<4);
				}
			}
			catch(NumberFormatException e)
			{
				winSTR = JOptionPane.showInputDialog("Only numbers are permitted. Enter the number of connects needed to win (4-8)");
				winCOUNT++;
			}
		}
	}
}

[Jacob Coddaire]

I can't figure out how to make it show a list of names, or anything , for that matter.

[Christophe Verré]

You should be using a showInputDialog instead :

		String selectedPlayerName = (String)JOptionPane.showInputDialog(null,
				"Which player will play first?", "Player Selection",
				JOptionPane.PLAIN_MESSAGE, null,
				playerArray, playerArray[0]);

(there are some examples in the java tutorial)

[Jacob Coddaire]

This works, but it has a small defect. I can select a blank space when there is nothing there. Is there a way to work around this?

[Janeice DelVecchio]

Jacob,

Did you see the tutorial? If so,

Object[] possibilities = {"ham", "spam", "yam"};
// possibilities would be the array of selectable items.... 
// not the same as the 4 index array (unless there's 4 players)
String s = (String)JOptionPane.showInputDialog(
                    frame,
                    "Complete the sentence:\n"
                    + "\"Green eggs and...\"",
                    "Customized Dialog",
                    JOptionPane.PLAIN_MESSAGE,
                    icon,
                    possibilities,
                    "ham");

Your best bet would be to initialize the array once you find out how many players there will be. Then you can just use that array in the input dialog. Otherwise, you'll need to create another array once you figure out there's only 2 players or whatever.

[Jacob Coddaire]

Ok I got it to work. Sweet and thanks.