NullPointerException - Ticks - getHeldItem()

[BadBoy6767]

Hey everyone, i have a NullPointerException problem, i know what it is an all since i experienced java for 4 years,

though, i have no idea how to avoid it since i rarely had this problem,

im trying to check the item held by the player in a tick event.

 

This is the main file:

 

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package com.lvivtotoro.forgemod.interruptuswandus;

 

import net.minecraft.creativetab.CreativeTabs;

import net.minecraft.init.Blocks;

import net.minecraft.init.Items;

import net.minecraft.item.Item;

import net.minecraft.item.ItemStack;

import cpw.mods.fml.common.FMLCommonHandler;

import cpw.mods.fml.common.Mod;

import cpw.mods.fml.common.Mod.EventHandler;

import cpw.mods.fml.common.event.FMLPreInitializationEvent;

import cpw.mods.fml.common.registry.GameRegistry;

import cpw.mods.fml.common.registry.LanguageRegistry;

 

@Mod(modid = InterruptusWandus.MODID, version = InterruptusWandus.VERSION)

public class InterruptusWandus {

 

public static final String MODID = "interruptuswandus";

public static final String VERSION = "0.1";

 

public static final Item emptyWand = new Item().setUnlocalizedName(

"wandEmpty").setTextureName(MODID + ":emptyWand");

public static final Item fireWand = new ItemFireWand().setUnlocalizedName(

"wandFire").setTextureName(MODID + ":fireWand");

public static final Item iceWand = new ItemIceWand().setUnlocalizedName(

"wandIce").setTextureName(MODID + ":iceWand");

public static final Item lightningWand = new ItemLightningWand()

.setUnlocalizedName("wandEl").setTextureName(MODID + ":elWand");

 

@EventHandler

public void preInit(FMLPreInitializationEvent e) {

FMLCommonHandler.instance().bus().register(new LightningWandTickHandler());

GameRegistry.registerItem(emptyWand, "iwEmptyWand");

emptyWand.setCreativeTab(CreativeTabs.tabTools);

LanguageRegistry.addName(emptyWand, "Empty Wand");

GameRegistry.addRecipe(new ItemStack(emptyWand, 1), new Object[] {

" G", "S ", 'G', Blocks.glass, 'S', Items.stick });

GameRegistry.registerItem(fireWand, "iwFireWand");

fireWand.setCreativeTab(CreativeTabs.tabTools);

LanguageRegistry.addName(fireWand, "§cFire Wand");

GameRegistry.addRecipe(new ItemStack(fireWand, 1), new Object[] {

"FSF", "DWD", "III", 'F', Items.flint, 'S',

Items.flint_and_steel, 'I', Items.iron_ingot, 'W', emptyWand });

GameRegistry.registerItem(iceWand, "iwIceWand");

iceWand.setCreativeTab(CreativeTabs.tabTools);

LanguageRegistry.addName(iceWand, "§3Ice Wand");

GameRegistry.addRecipe(new ItemStack(iceWand, 1), new Object[] { "FFF",

" W ", "III", 'F', Blocks.ice, 'I', Items.diamond, 'W',

emptyWand });

GameRegistry.registerItem(lightningWand, "iwLightningWand");

lightningWand.setCreativeTab(CreativeTabs.tabTools);

LanguageRegistry.addName(lightningWand, "§5Lightning Wand");

GameRegistry.addRecipe(new ItemStack(lightningWand, 1), new Object[] { "FFF",

" W ", "FFF", 'F', Items.glowstone_dust,

'W', emptyWand });

}

 

}

 

 

 

This is the event:

 

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package com.lvivtotoro.forgemod.interruptuswandus;

 

import net.minecraft.client.Minecraft;

import net.minecraft.client.entity.EntityClientPlayerMP;

import net.minecraft.item.Item;

import net.minecraft.potion.Potion;

import net.minecraft.potion.PotionEffect;

import cpw.mods.fml.common.eventhandler.SubscribeEvent;

import cpw.mods.fml.common.gameevent.TickEvent.ClientTickEvent;

 

public class LightningWandTickHandler {

 

@SubscribeEvent

public void onUpdate(ClientTickEvent event) {

EntityClientPlayerMP p = Minecraft.getMinecraft().thePlayer;

if(InterruptusWandus.lightningWand.equals(p.getHeldItem())) {

if(!p.capabilities.isCreativeMode) {

p.addPotionEffect(new PotionEffect(Potion.moveSlowdown.id, 1, 1));

p.addPotionEffect(new PotionEffect(Potion.damageBoost.id, 1, 1));

}

}

}

 

}

 

 

[Kwibble]

Either this is being called before the player actually spawns, or the players held item is null.

 

 

Also, why aren't you using the onUpdate method in your custom item class? It gets called whenever the item is in the players inventory which means you could do your check from there.

[BadBoy6767]

Guys, 60% of your posts were pointless ,

i inserted the onUpdate method in the item class, the same thing is happening!

 

[Kwibble]

And from your "60% worthless" post right there I assume you just copy/pasted the exact same code you had in the event handler. So of course its not going to work. As diesieben07 kindly told you:

  Quote

a) This won't work, you can't add PotionEffects on the client.

 

So you need to use the parameters given in the method, but first surround it all with a check to see if the world is server side world.