Java final projec trouble

[super_teabag]

Having a bit of trouble with this method that i'm trying to create a method for a project.

public void show (){        String result = "";        if(ItemsHeld.get(1)==null){            msg = "The player is not holding anything.";        }        else{            for(Item objects: ItemsHeld){                result += objects.getName()+ " ";            }            msg = "You are holding " + result;        }    } 

This method is designed to check if there's items in a player inventory.

 

The Item has 3 methods in it's class "getname()" returns the name of the object.

getLongdescription() which returns the long descriptions of the item.

and getweight() which gets the weight of the object as an integer.

 

The items are stored in an arraylist called "ItemsHeld".

 

At this point in time there's nothing in the arraylist of Items.

 

There's two scenarios that could happen one you can return all the items in the players inventory to at msg.

Secondly, the player has no items in his/her inventory and returns 'you don't have any items.'

 

The compiler is giving me an error about a null pointer, saying something about the size of the array list

Idk how to check if a players inventory doesn't contain anything without some kind of error popping up.

 

 

 

 

 

[kichilron]

Are you aware that the first thing in an array is position 0 and not 1?

 

Also:

 

You can check the length of an Array in Java.

[Ghost]

You are getting a null pointer exception because you are trying to check a position of the array list that doesn't exist.

 

Use:

ArrayList.isEmpty();

[madknight3]

Since the items are stored in an array list you can use .size()

if (itemList.size() > 0) {    //...}

edit: Forgot about the isEmpty method, better to use that as @Ghost suggests above.

[super_teabag]

yeah i've tried that first, and i knew that the first index starts at 0. Such as itemsheld.get(0) will return the first indexed item.

 

i've also tried ItemsHeld.size()=0 in my if statement, but here's the error i keep getting.

 

at java.util.ArrayList.rangeCheckForAdd(ArrayList.java:612)
at java.util.ArrayList.add(ArrayList.java:426)
at Game.show(Game.java:218)
at Game.main(Game.java:269)
 

[Ghost]

 

Since the items are stored in an array list you can use .size()

if (itemList.size() > 0) {    //...} 

How would that be better than what he already has: "for(Item objects: ItemsHeld)" will do the same as the if statement if there are no Items in the ArrayList.

[Ghost]

yeah i've tried that first, and i knew that the first index starts at 0. Such as itemsheld.get(0) will return the first indexed item.

 

i've also tried ItemsHeld.size()=0 in my if statement, but here's the error i keep getting.

Use == for comparisons. A single = is used for declerations.

[madknight3]

How would that be better than what he already has: "for(Item objects: ItemsHeld)" will do the same as the if statement if there are no Items in the ArrayList.

Doing the check is not the same as his current code. Also you can negate it or add an else depending on what you need from it so it's not the same as a for statement either.

 

Anyway, I forgot about isEmpty and edited my post. It's a better option than checking size anyway.

[Ghost]

Doing the check is not the same as his current code. Also you can negate it or add an else depending on what you need from it so it's not the same as a for statement either.

 

Anyway, I forgot about isEmpty and edited my post. It's a better option than checking size anyway.

This code requires no size()

public void show (){        if(!ItemsHeld.isEmpty()){            msg = "You are holding ";            for(Item objects: ItemsHeld){                msg += objects.getName()+ " ";            }            return;        }        msg = "The player is not holding anything.";    }

[madknight3]

This code requires no size()

I am aware. You either didn't read what I said or didn't understand it.

[Midnight]

yeah i've tried that first, and i knew that the first index starts at 0. Such as itemsheld.get(0) will return the first indexed item.

 

i've also tried ItemsHeld.size()=0 in my if statement, but here's the error i keep getting.

 

at java.util.ArrayList.rangeCheckForAdd(ArrayList.java:612)

at java.util.ArrayList.add(ArrayList.java:426)

at Game.show(Game.java:218)

at Game.main(Game.java:269)

 

 

What is the code at line 218?

[super_teabag]

@Midnight @madknight3 @Ghost

Thanks for all the help. that "isEmpty()" method is awesome I didn't know it existed as part of the arraylist library.

 

I got the errors worked out, and the method works now. Thanks for the help guys!