Thread: Arraylits for handling errors?

Hey!
Im new to java...and programming in general. Im trying to make a program where the user can input 3 fields. I want the program to tell the user what fields the user forgot to fill in.
Can I use an arraylist for that? Help would be greatly appreciated It doesnt work like iwaHere is my code:

for (;;) {
				try {
 
 
 
					int svar = JOptionPane.showConfirmDialog(Main.this, reg,
							"Registrera deltagare",
							JOptionPane.OK_CANCEL_OPTION);
 
					if (svar != OK_OPTION)
						return;
 
					ArrayList<String> errorlog = new ArrayList<String>();
 
					String name = reg.getName();
					String country = reg.getCountry();
					String age = reg.getAge();
 
					if (age.length()==0); 
						errorlog.add("Ålder");
					if (name.length()==0)
						errorlog.add("Namn");
					if (country.length()==0) {
						errorlog.add("Land");
						System.out.println(age);
					JOptionPane.showMessageDialog(Main.this, "You forgot to fill in: "+errorlog,
							"Problem", JOptionPane.ERROR_MESSAGE); } 
					else {
					int age2 = Integer.parseInt(age);	
					People p = new People(name, country, age2);
					persons.add(p);
					startnr++;
					break;
					}
				} catch (NumberFormatException e) {
 
					JOptionPane.showMessageDialog(Main.this, "Only numbers in this field, please.",
							"Fel", JOptionPane.ERROR_MESSAGE);
				}
 
			}

Originally Posted by Norm

What is the reg variable? It looks like a class with methods that are used to get user input.


The code already does something like that with the errorlog variable. What is the problem with how that works?
The posted code can't be compiled for testing. Can you post a small complete program that compiles, executes and shows the problem.

Hey, thanks for the answer. reg is the form from where i get user input.
The problem is that it doesnt work correct. Ill try to explain...

If i type nothing, it works correct (tells me i forgot name, country and age)
If i type only name, it works correct (tells me i forgot country and age)

If i type name and age, it doesnt work (tells me i forgot country and age)
If i type country and age, it doesnt work (it doesnt tell me i forgot the name at all)


etc... is it something wrong with the brackets or is it something else?

Please help!

Where should I write the system.out.print?


I know this is going to be a lot of code...but im pasteing it here anyway. I think you can help me better if you see all of it.

Here it goes:

import static javax.swing.JOptionPane.OK_OPTION;
 
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
 
public class Main extends JFrame {
	int startnr = 1;
	JTextArea textarea = new JTextArea();
	ArrayList<People> persons = new ArrayList<People>();
 
	Main() {
		super("DSV Kista Marathon");
		setLayout(new BorderLayout());
 
		JPanel north = new JPanel();
		north.add(new JLabel("DSV Marathon"));
		add(north, BorderLayout.NORTH);
 
		JPanel south = new JPanel();
		JButton registerNew = new JButton("Ny");
		registerNew.addActionListener(new RegisterListener());
		JButton show = new JButton("Visa");
		show.addActionListener(new ShowListener());
		JButton time = new JButton("Tid");
		time.addActionListener(new TimeListener());
		south.setLayout(new FlowLayout(FlowLayout.LEFT));
		south.add(registerNew);
		south.add(show);
		south.add(time);
		add(south, BorderLayout.SOUTH);
 
		JPanel east = new JPanel();
		JPanel eastSouth = new JPanel();
		eastSouth.setLayout(new BoxLayout(eastSouth, BoxLayout.Y_AXIS));
		east.setLayout(new BorderLayout());
		east.add(eastSouth, BorderLayout.SOUTH);
		eastSouth.add(new JLabel("Sortering"));
 
		ButtonGroup knappgrupp = new ButtonGroup();
		JRadioButton sortStartNr = new JRadioButton("Startnr", true);
		JRadioButton sortName = new JRadioButton("Namn");
		JRadioButton sortAge = new JRadioButton("Ålder");
		JRadioButton sortTime = new JRadioButton("Tid");
		knappgrupp.add(sortStartNr);
		knappgrupp.add(sortName);
		knappgrupp.add(sortAge);
		knappgrupp.add(sortTime);
 
		eastSouth.add(sortStartNr);
		eastSouth.add(sortName);
		eastSouth.add(sortAge);
		eastSouth.add(sortTime);
		add(east, BorderLayout.EAST);
 
		JScrollPane scroll = new JScrollPane(textarea);
 
		textarea.setEditable(false);
		add(scroll);
 
		setVisible(true);
		setSize(400, 500);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
 
	}
 
	class Register extends JPanel {
		JTextField nameField = new JTextField(10);
		JTextField countryField = new JTextField(10);
		JTextField ageField = new JTextField(3);
 
		public Register() {
 
 
			setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
			JLabel rubrik = new JLabel ("Startnr: "+startnr); 
			JPanel row1 = new JPanel(new FlowLayout(FlowLayout.LEFT));
			add(rubrik);
			row1.add(new JLabel("Namn:"));
			row1.add(nameField);
			add(row1);
 
 
			JPanel row2 = new JPanel(new FlowLayout(FlowLayout.LEFT));
			row2.add(new JLabel("Land: "));
			row2.add(countryField);
			add(row2);
 
			JPanel row3 = new JPanel(new FlowLayout(FlowLayout.LEFT));
			row3.add(new JLabel("Ålder:"));
			row3.add(ageField);
			add(row3);
 
 
 
 
 
		}
 
		public String getName() {
			return nameField.getText();
		}
 
		public String getCountry() {
			return countryField.getText();
		}
 
		public String getAge() {
			return ageField.getText();
		} 
 
		/*public int getAge() {
			return Integer.parseInt(ageField.getText());
		} */
	}
 
	class RegisterListener implements ActionListener {
		public void actionPerformed(ActionEvent event) {
			Register reg = new Register();
 
			for (;;) {
				try { 
 
 
 
					int svar = JOptionPane.showConfirmDialog(Main.this, reg,
							"Registrera deltagare",
							JOptionPane.OK_CANCEL_OPTION);
 
					if (svar != OK_OPTION)
						return;
 
					ArrayList<String> errorlog = new ArrayList<String>();
 
					String name = reg.getName();
					String country = reg.getCountry();
					String age = reg.getAge();
 
					if (name.length()==0) 
						errorlog.add("Namn"); 
					if (country.length()==0) 
						errorlog.add("Land");	
					if (age.length()==0) {
						errorlog.add("Ålder"); 
					JOptionPane.showMessageDialog(Main.this, "Du glömde: "+errorlog,
							"Fel", JOptionPane.ERROR_MESSAGE); } 
					else {
					int age2 = Integer.parseInt(age);	
					People p = new People(name, country, age2);
					persons.add(p);
					startnr++;
					break;
					}
				}catch (NumberFormatException e) {
 
					JOptionPane.showMessageDialog(Main.this, "Du måste skriva siffror",
							"Fel", JOptionPane.ERROR_MESSAGE);
				}
 
			}
 
 
		}
 
	}
 
	class ShowListener implements ActionListener {
		public void actionPerformed(ActionEvent event) {
 
		}
 
	}
 
	class TimeListener implements ActionListener {
		public void actionPerformed(ActionEvent event) {
			System.out.println(persons);
		}
	}
 
	public static void main(String[] args) {
		new Main();
	}
 
}

--- Update ---

I've done what you told me...it seems that the if (country.length()==0) statement doesnt work...because it saves the country variable even if the length is 0...
Here is the system.out.print you told me to do if i type Name: Steve, Country: (empty), Age: 28

Name/Namn: Steve
Country/Land:
Age/Ålder: 28

Originally Posted by Norm

Can you explain what you mean here when you say "saves"?

When does the code in post #5 execute the JOPtionPane statement that shows the error message?
What is the condition tested in the if statement that controls its execution?

When do you want the error message to be displayed? Does the code do that?

By saves i mean creates a object of the class People and adds that to the array persons.

Im really appreciating your help. Im going to record a video that illustrates the problem

EDIT: http://www.youtube.com/watch?v=3pT9Z...ature=youtu.be

Tell me if the quality is to bad, i think you get the idea.

Oh...ok, could this be the problem? What line is this?
Here is the video illustrating the problem:

Problem - YouTube

Change to HD to see text better!

Hmmm..i cant seem to post new posts anymore...
Trying again:

Problem - YouTube

by save i mean create object of the class people and add to the persons arraylist.

No, I cant find that bracket. What line is it?

When does the code in post #5 execute the JOPtionPane statement that shows the error message?

When user press OK (ie. when svar is = OK_OPTION).

What is the condition tested in the if statement that controls its execution?

I guess i just answered this, or didnt I? My english is not that good.

When do you want the error message to be displayed? Does the code do that?

When any field is left empty. Yes, it works sometimes and sometimes not. See post#3.

--- Update ---

I've tried the code a little bit more now.
It seems that aslong as i enter an age. The program doesnt care about the two fields above...