Array returning null value

Question

I'm getting a little confused with Arrays and was hoping that someone could help me out.

I hope this makes sense because I am a bit confused. Any help is much appreciated!

The while loop creating the objects in class 'League'

     while (lineScanner.hasNextLine())
       {
       currentLine = lineScanner.nextLine();
           String[] newSSs = currentLine.split(","); 
           Team team = new Team(newSS[0]);
           team.setWins(Integer.valueOf(newSS[1]));
           team.setDraws(Integer.valueOf(newSS[2]));
           team.setLoses(Integer.valueOf(newSS[3]));
           team.setPoints(team.calculatePoints());

I'm too a bit confused... Where are the ArrayLists in your code? — davide
– davide, Commented May 10, 2015 at 19:38
Can you post more code? It's not clear from the code you posted what the problem is. I see no ArrayList in that code. — Eran
– Eran, Commented May 10, 2015 at 19:38
Still I don't see the ArrayList... I think you should post more of your League.class (and most likely the stuff you have around your while loop) — davide
– davide, Commented May 10, 2015 at 19:52
In my League class I have "private Team[] teams;" If I add an ArrayList I get 2 Arrays (one from class Team) and one from the ArrayList. The ArraList gets all the information and the Array from class values all return as null. Also thank you so far, I'm completely new with this! — sobm
– sobm, Commented May 10, 2015 at 19:55
All of the answers are saying replace private Team[] teams with private ArrayList<Team> team. Are you just dead set on using an array? — Shar1er80
– Shar1er80, Commented May 10, 2015 at 20:33

Suspended · Accepted Answer · 2015-05-10 19:42:44Z

1

I guess I know what you're trying to do... Create one ArrayList before your while loop (you need a collection of some kind to store your parsed teams):

private ArrayList<Team> teams = new ArrayList<Team>();

while (lineScanner.hasNextLine()){
    currentLine = lineScanner.nextLine();
    String[] newSSs = currentLine.split(","); 
    Team team = new Team(newSS[0]);
    team.setWins(Integer.valueOf(newSS[1]));
    team.setDraws(Integer.valueOf(newSS[2]));
    team.setLoses(Integer.valueOf(newSS[3]));
    team.setPoints(team.calculatePoints());
}

You really have just one array - the one that holds teams. Lifetime of newSSs is limited to one pass through the loop and once lineScanner does not have more lines to process, the loop ends and newSSs is disposed of.

I hope it helps

answered May 10, 2015 at 19:42

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user4624062 · Accepted Answer · 2015-05-10 19:43:15Z

1

I am guessing:

  ArrayList<Team> list = new ArrayList<Team>();
  for(int i=0;i<5;i++)
     list.add(null);

   //change values
    list.set(0,new Team(newSS[0]);
    list.get(0).setWins(Integer.valueOf(newSS[1]));

answered May 10, 2015 at 19:43

user4624062

Comments

Razib · Accepted Answer · 2015-05-10 19:43:13Z

0

I think you Team class has the following methods -

setWins()
setDraws()
setLoses()
setPoints()

But here you are trying to use these method form a Team team which you have declared as an array -

Team team = new Team(newSS[0]);

Since here team is a array of Team try to do this -

team[0].setWins(Integer.valueOf(newSS[1]));
team[0].setDraws(Integer.valueOf(newSS[2]));
team[0].setLoses(Integer.valueOf(newSS[3]));

answered May 10, 2015 at 19:43

Razib

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1 Comment

Suspended Over a year ago

Team team = new Team(newSSs[0]); ---> I think this just passes Team's name stored in newSSs[0] to Team's constructor.

vyncjob · Accepted Answer · 2015-05-10 19:55:59Z

0

From the code snippet it seems you want to store team details in a Team object. However you have many Team objects and you want an array of them. This comes close:

ArrayList<Team> teamList = new ArrayList<Team>();
while (lineScanner.hasNextLine())
   {
   currentLine = lineScanner.nextLine();
       String[] newSSs = currentLine.split(","); 
       Team team = new Team(newSS[0]);
       team.setWins(Integer.valueOf(newSS[1]));
       team.setDraws(Integer.valueOf(newSS[2]));
       team.setLoses(Integer.valueOf(newSS[3]));
       team.setPoints(team.calculatePoints());
teamList.add(team);
}

Java 7 ArrayList Java 8 ArrayList

answered May 10, 2015 at 19:55

vyncjob

215 bronze badges

1 Comment

sobm Over a year ago

When I use this I get 'actual argument Team[] cannot be converted to Team by method invocation conversion)'

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