Calling methods from objects stored in an arraylist

Question

I was wondering why this isn't working. I looked at another post that suggested the method I used for calling methods from Objects stored in an array but it doesn't seem to be working. I should clarify. I am referring to the printPurchases and totalCost methods. More specifically how they don't seem to be allowing me to call from the Purchase object at index i, but instead appear to be calling from the get(i) part. It is highlighted in red in my eclipse application.

public class Customer {

    private String name, address;
    double total;
    private ArrayList purchases = new ArrayList();

    public Customer(String name, String address){
        this.address=address;
        this.name=name;
    }

    public void makePurchase(Purchase purchase){
        purchases.add(purchase);
    }

    public String printPurchases(){
        for(int i=0; i<purchases.size(); i++){
            return **name+"\t"+address+purchases.get(i).toString();**
        }
        return"";
    }

    public double totalCost(){
        total=0;
        for(int i=0; i<purchases.size(); i++){
            total = **total+purchases.get(i).getCost();**
        }
    }
}

when using the List interface, specify what object you are storing. in your case, add <Purchase> after ArrayList — Moddl
– Moddl, Commented Feb 26, 2015 at 1:49

Jonny Henly · Accepted Answer · 2015-02-26 01:55:31Z

1

Your return statement should have a space in between return and "".

public String printPurchases(){
    for(int i=0; i<purchases.size(); i++){
        return name+"\t"+address+purchases.get(i).toString();
    }
    return "";
}

public double totalCost() is suppose to return a double. You aren't returning a double.

public double totalCost(){
    total=0;
    for(int i=0; i<purchases.size(); i++){
        total = total+purchases.get(i).getCost();
    }

    return total;
}

Also, as said in the comments, specify what the ArrayList is to be filled with, by using:

private ArrayList<Purchase> = new ArrayList<Purchase>();

edited Feb 26, 2015 at 1:55

answered Feb 26, 2015 at 1:50

Jonny Henly

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Comments

armnotstrong · Accepted Answer · 2015-02-26 02:04:21Z

1

The type information, ie the attr and method of Purchase will be erased (upcast to Object, with no self-defined attr or method) when you stored them in a ArrayList with no Generic Type, try store them like this:

private ArrayList<Purchase> purchases = new ArrayList<>();

edited Feb 26, 2015 at 2:04

answered Feb 26, 2015 at 1:58

armnotstrong

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