Array of JLabel object initializing issue

Question

So, I initialized it as an array object, and when I go to initialize the individual objects,it won't give them a value

/* 
-A java program GUI for Food to allow user to type the food 
*/
public class Catagorygui extends JFrame implements ActionListener{

//attributes
JPanel panel;   
JButton button; 
JFrame frame;   
JLabel item;    
JTextField item1;   
JLabel cost;    
JTextField cost1;   
JLabel percentused; 
JLabel name;    
JTextField name1;   
JLabel paidupfront; 
JTextField paidupfront1;

public Appartment2 g=new Appartment2();

private static String rec=" ";

private JTextField [] upfront=new JTextField[g.getPeople().size()];//must initialize
private JTextField [] percent=new JTextField[g.getPeople().size()];
private JLabel [] usernames=new JLabel[g.getPeople().size()];//for loop that gives them values
private int a;

public Catagorygui (){
    g.addPerson("Ali");
    g.addPerson("Kacie");

    for(int i=0;i<a;i++)
    {

        usernames[i]=new JLabel("poop");//somehow not initializing it
        percent [i]=new JTextField(10);
        upfront [i]=new JTextField(10);
        percent[i].addActionListener(this);
    }
    System.out.println(g.getpeople().get(0).getName());//ali
    System.out.print(usernames[0]);//SAYS INDEX OUT OF BOUNDS, should say'poop'
    //
    a=g.getpeople().size();

If usernames[0] throws index out of bounds, that means the array size is 0. — Jorn Vernee
– Jorn Vernee, Commented Apr 16, 2016 at 15:09

Jack · Accepted Answer · 2016-04-16 15:02:24Z

2

for (int i=0; i<a; i++)

Yes, keep iterating while i < a, but what's a? Where did you initialize it? Any int primitive type has a default value of 0 in Java. so 0 < 0 is always false and no iterations are done.

answered Apr 16, 2016 at 15:02

Jack

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Evgeny · Accepted Answer · 2016-04-16 15:05:18Z

0

a=g.getpeople().size(); should be before the for loop

answered Apr 16, 2016 at 15:05

Evgeny

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2 Comments

Gaurav Dave Over a year ago

This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - From Review

Evgeny Over a year ago

@GauravDave It is not request for clarification or criticism. It is explanation why the code doesn't work as expected.

Community · Accepted Answer · 2020-06-20 09:12:55Z

0

You are almost there, just a move a little some variables...

the for loop is not executed because a is not initialized (or it is, but at the end of the constructor...) just move the assign of the variable a before you go in the for loop and not the error must be gone! a=g.getpeople().size();

Example:

public Catagorygui (){
    g.addPerson("Ali");
    g.addPerson("Kacie");
    a = g.getpeople().size();   // move up to here
    for(int i=0;i<a;i++)
    {
        usernames[i]=new JLabel("poop");//somehow not initializing it
        percent [i]=new JTextField(10);
        upfront [i]=new JTextField(10);
        percent[i].addActionListener(this);
    }
    System.out.println(g.getpeople().get(0).getName());//ali
    System.out.print(usernames[0]);//SAYS INDEX OUT OF BOUNDS, should say'poop'
        //

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Apr 16, 2016 at 15:08

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