I am making custom attributes for players in my mod but when I try to add a modifier to the player it crashes with the message "Cannot invoke "net.minecraft.world.entity.ai.attributes.AttributeInstance.addTransientModifier(net.minecraft.world.entity.ai.attributes.AttributeModifier)" because the return value of "net.minecraft.world.entity.player.Player.getAttribute(net.minecraft.world.entity.ai.attributes.Attribute)" is null". 

Main Mod Class:

public truffleMod() {
		IEventBus bus = FMLJavaModLoadingContext.get().getModEventBus();
		
		
		
		
		
		ItemInit.ITEMS.register(bus);
		ModEffects.register(bus);
		
		MinecraftForge.EVENT_BUS.register(this);
		
		
        modAttributes.ATTRIBUTES.register(bus);
		
		
	}
	

Attribute Registrey:

package data.trufflemod.attributes;

import java.util.UUID;

import com.ND0322.trufflemod.truffleMod;

import net.minecraft.world.entity.ai.attributes.Attribute;
import net.minecraft.world.entity.ai.attributes.RangedAttribute;
import net.minecraftforge.registries.DeferredRegister;
import net.minecraftforge.registries.ForgeRegistries;
import net.minecraftforge.registries.RegistryObject;

public class modAttributes {
	public static final DeferredRegister<Attribute> ATTRIBUTES = DeferredRegister.create(ForgeRegistries.ATTRIBUTES, truffleMod.MOD_ID);
	
	//ATTRIBUTES
	public static final RegistryObject<Attribute> CRIT_CHANCE = ATTRIBUTES.register("crit_chance", () -> (Attribute) new RangedAttribute(truffleMod.MOD_ID + ".playerCritChance", 4, 0, 100).setSyncable(true));
	
	
}

EventHandler:

@SubscribeEvent
	public static void onEntityAttributeModificationEvent(EntityAttributeModificationEvent event) {
		event.add(EntityType.PLAYER, modAttributes.CRIT_CHANCE.get());
		
	}
	@SubscribeEvent
	public static void onEvent(EntityJoinWorldEvent event) {
	      if ((event.getEntity() instanceof Player)) {
	    	  Player player = (Player)event.getEntity();
	    	  
	    	  
	    	 
    	 
	    	 
	    	  AttributeModifier CRIT_CHANCE = new AttributeModifier(UUID.fromString("fb84a4dd-8592-48f7-8e47-911987651d42"), "damage modifier", stats.getDamageMultiplier(), AttributeModifier.Operation.MULTIPLY_TOTAL);
		  		
	  		  
	  	   
	  		
	  		 player.getAttribute(modAttributes.CRIT_CHANCE.get()).addTransientModifier(CRIT_CHANCE);
	  		
	  		   
	    	  
	    	  
	      }
	  }
	

What might be causing this error?

The error says it doesn't have the attribute.

Hard to tell because you don't show the full context, but I guess you are listening on the main event bus instead of the mod event bus for the EntityAttributeModificationEvent?

 

Its a good idea to put configuration and runtime code in different classes.

I moved the EntityAttributeModification to another class and setup a listener in the main mod class but I get the same error

public class EventHandler {
	
	@SubscribeEvent
	public static void onEntityAttributeModificationEvent(EntityAttributeModificationEvent event) {
		event.add(EntityType.PLAYER, modAttributes.CRIT_CHANCE.get());
		
	}
}

public truffleMod() {
		IEventBus bus = FMLJavaModLoadingContext.get().getModEventBus();
		IEventBus eventBus = MinecraftForge.EVENT_BUS;
		
		
		
		
		ItemInit.ITEMS.register(bus);
		ModEffects.register(bus);
		modAttributes.ATTRIBUTES.register(bus);
		 
		MinecraftForge.EVENT_BUS.register(this);
		
        eventBus.addListener(EventHandler::onEntityAttributeModificationEvent);
		
		
        
        
      
		
       
		
		
	}

 

That code is still not using the Mod EventBus, your "bus" variable.

You can also do it like this:

@Mod.EventBusSubscriber(modid = MODID, bus = Mod.EventBusSubscriber.Bus.MOD)
public class EventHandler {
	
	@SubscribeEvent
	public static void onEntityAttributeModificationEvent(EntityAttributeModificationEvent event) {
		event.add(EntityType.PLAYER, modAttributes.CRIT_CHANCE.get());
		
	}
}

 

Thanks! It works great.

40 minutes ago, warjort said:

That code is still not using the Mod EventBus, your "bus" variable.

this was not the issue, the EventHandler was not correctly registered, see:

One more question: how do i run the CriticalHitEvent. It does not let me register it in the main mod class and when I just @SubscribeEvent in an event handler, it does not fire

 

I would like to disable vanilla critical hits

nvm i figured this out