NPE in listener

Here's my code

Code:

@EventHandler
    public void onInteract(PlayerInteractEvent event) {
        // Check for right click
        if (event.getAction() == Action.RIGHT_CLICK_AIR || event.getAction() == Action.RIGHT_CLICK_BLOCK) {
            // Check for item
            if (event.hasItem()) {
                // Check for radio
                if (Radio.isRadio(event.getItem())) {
                    // Get item
                    ItemStack stack = event.getItem();
                    boolean state;
                    // Check current state
                    if (stack.getType() == Material.REDSTONE_LAMP_ON) {
                        // Set it to off
                        stack.setType(Material.REDSTONE_LAMP_OFF);
                        state = false;
                    } else {
                        // Set it to on
                        stack.setType(Material.REDSTONE_LAMP_ON);
                        state = true;
                    }
                    // Now manipulate the meta
                    ItemMeta meta = stack.getItemMeta();
                    List<String> lore = meta.getLore();
                    lore.set(3, Radio.getStateString(state));
                    meta.setLore(lore);
                    stack.setItemMeta(meta);
                }
            }
        }
    }

And I get an NPE on the like with List<String> lore = meta.getLore();

What is going on here? The method Radio.isRadio() checks within that the item has a meta and lore, so it should be working. Also, the NPE is thrown when this listener is called, but the item im holding has a lore already!

 

@Pocketkid2
meta is null. Check if meta is null before getting the lore.

 

@Pocketkid2 The ItemMeta will normally not be null, but the Lore can, check if the meta #hasLore before trying to use it, also, it's good practice to also check if the item #hasItemMeta

 

The method Radio.isRadio() Should have checked that the meta and lore are both valid.

 

but it didn't

 

Well then I am not sure because A) I know that method checks because I just checked and B) The item this is being called on does in fact have a meta (It was set explicitly earlier, and also, why would it not have a meta if it has a displayname and lore?)

 

@Pocketkid2 Could we please see the "isRadio()" method then?

 

Code:

public static boolean isRadio(ItemStack stack) {
        if (stack.getType() == Material.REDSTONE_LAMP_ON || stack.getType() == Material.REDSTONE_LAMP_OFF) {
            if (stack.hasItemMeta()) {
                ItemMeta meta = stack.getItemMeta();
                if (meta.hasDisplayName() && meta.getDisplayName().equalsIgnoreCase("Radio")) {
                    if (meta.hasLore()) {
                        List<String> lores = meta.getLore();
                        if (!Radio.tier.matcher(lores.get(0)).matches()) {
                            return false;
                        }
                        if (!Radio.radius.matcher(lores.get(1)).matches()) {
                            return false;
                        }
                        if (!Radio.frequency.matcher(lores.get(2)).matches()) {
                            return false;
                        }
                        if (!Radio.state.matcher(lores.get(3)).matches()) {
                            return false;
                        }
                        return true;
                    }
                }
            }
        }
        return false;
    }

 

What's Radio.tier.matcher

 

It's a regex class that I'm using to parse the lore format. But it doesn't matter here, and I've tested it so I know it's working.

 

Is the NPE on this line specifically?

Code:

 List<String> lore = meta.getLore();

Because if the Lore is null, an NPE won't be thrown here specifically, but if the meta is null, it will. So if it's here I'm guessing it's a question of the meta its self being null

I think i maybe figured it out.. maybe

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Up at the first code snippet on line 8 I'm calling Radio.isRadio().
The only return true statement in that function is after some IF statements that check if the stack A) has a item meta B) Has a display name AND C) has a lore.

Now back to the first one. All I'm doing after Radio.isRadio() is pulling the itemstack, updating its information, and getting the meta so that I can edit it further. Something funky is up here.

 

Oh just a word for the future (this isnt the problem), when you're looking through a list of something, make sure the size of the list isnt smaller than the index of what you're looking for, just in case you get an ArrayIndexOutOfBounds exception sometime