Can't call defined method on Arraylist

Question

I'm having trouble with a class I wrote containing an ArrayList. Code:

import java.util.ArrayList;


public class AscendingPile {
 public ArrayList<Integer> pile = new ArrayList<Integer>() {{
     add(1);
 }};

public void lay(int card) throws IllegalArgumentException{
    int lastCard = pile.get(pile.size() - 1);
    if(card > lastCard || card == lastCard - 10){
        pile.add(card);
    }
    else {
        throw new IllegalArgumentException("....");
    }
}
// returns last card on the deck
public int getCard() {
    return pile.get(pile.size() - 1);
}

}

Problem is the lay method: Instead of defining a new local variable I want the if statement to look something like this:

if(card > pile.getCard() || card == pile.getCard() - 10)

but IntelliJ says cannot resolve symbol getCard()

How can I change my code to obtain the desired result?

That's because `getCard()` is not a method defined on `ArrayList`. — azurefrog, Mar 15 '17 at 14:46
`getCard` is not a method of class `ArrayList`, so you cannot call `getCard` on `pile` which is what you are doing: `pile.getCard()`. Just call `getCard()`, not `pile.getCard()`. — Jesper, Mar 15 '17 at 14:47
Also, check this, might be interesting for improving your code: http://stackoverflow.com/a/14072408/7709364 — Tanguy Labrador Ruiz, Mar 15 '17 at 15:07

score 1 · Answer 1 · answered Mar 15 '17 at 14:47

1

but IntelliJ says cannot resolve symbol getCard()

That is true, ArrayList class has no method called getCard()

instead of doing:

pile.getCard();

do call directly the method of the class AscendingPile

getCard();

answered Mar 15 '17 at 14:47

ΦXocę 웃 Пepeúpa ツ

47,427
17
69
97

Works fine! Thank you very much for the quick response :-) – fatso88 Mar 15 '17 at 14:52

score 0 · Answer 2 · answered Mar 15 '17 at 15:00

0

As already said, just call directly getCard().

I'm also currently coding a card game. Instead of using ArrayList for your deck, i strongly recommend you to use Stack instead. (see documentation https://docs.oracle.com/javase/7/docs/api/java/util/Stack.html).

Stack provides you useful methods like pop() and push().

Pop removes the object at the top of the stack, just like you're doing now with your getCard() method.

answered Mar 15 '17 at 15:00

Tanguy Labrador Ruiz

285
4
12

thank you for your feedback. Unfortunatelly it's an Assignment and we can't use Stack for now. But I'll keep it in mind for future projects! – fatso88 Mar 16 '17 at 00:03
I'm coding for assignments too, and i can tell you that taking initiatives is very relevant and well welcomed by teachers in this kind of cases :) – Tanguy Labrador Ruiz Mar 16 '17 at 08:51

Can't call defined method on Arraylist

2 Answers2