[Solved] [1.7.2] Preventing Players Harvesting Blocks With Their Fists

[qpwoeiruty]

I am trying to create a mod that makes the game more challenging, and so I would like to be able to remove the feature in vanilla Minecraft that allows the player to harvest wood through the power of their fist. However, I am not entirely sure how this would be possible as everywhere I looks seems to lead me back to changing the harvest level of the vanilla blocks, but this doesn't seem to do anything or I cannot get it working correctly. So I am wondering if anyone knew how this could be done, or could link me to any useful sources. If so this would be highly appreciated, thanks.

[larsgerrits]

Use the PlayerEvent.BreakSpeed event and cancled it or set the newSpeed to -1.

[qpwoeiruty]

Firstly, thanks for the fast reply, but I am quite new to modding and events seem to be something I cannot get my head round. Could you show me how I would go about this as I have tried some events before and couldn't get them working. Sorry if this is really simple, I just have a poor understanding of events.

[larsgerrits]

First,you need to make a class and register that in the MinecraftForge.EVENT_BUS. Then you need to make a method, eg. setBreakSpeed and put the PlayerEvent.BreakSpeed in that as a parameter. After that, put the @SubscribeEvent annotation above the method. In that method you can set the newSpeed of the event and that's it! If you need more help, post your code so we can help.

[qpwoeiruty]

Wow, thanks again for another quick reply, I will try that out now...

 

Well that was certainly one step in the right direction something is actually happening; the player can no longer break any blocks. However, they can't break any blocks with tools either which is not exactly what I wanted. Considering I entered one line of code inside my method I'm sure there is a way around this.

 

  @SubscribeEvent

public void setBreakSpeed(PlayerEvent.BreakSpeed event) {

 

event.setCanceled(true);

 

}

[larsgerrits]

In the event (or actually the parent class, which is PlayerEvent), you also get a EntityPlayer object, so you can use that to check if entityPlayer.getCurrentEquippedItem() is null and then cancel the event.

[qpwoeiruty]

Thanks once again, could you give me a quick example because my game crashes when I do it.

[coolboy4531]

We won't show you an example, you need to learn how to do it c:

 

Show us the code you used (that causes a game crash) and we can guide you through the process and your mistakes.

[qpwoeiruty]

Alright will do thanks...

 

I am using this and don't really understand whats wrong with it:

private boolean objectInHand = true;

@SubscribeEvent
public void objectInHand(EntityPlayer event) {

	if(event.getCurrentEquippedItem() != null) {

		objectInHand = false;

	}

}

@SubscribeEvent
public void setBreakSpeed(PlayerEvent.BreakSpeed event) {

	if(objectInHand = false) {

		event.setCanceled(true);

	} else {

		event.setCanceled(false);

	}

}

[larsgerrits]

In the PlayerEvent.BreakSpeed you are given an entityPlayer object. You can use that to get the current item instead of the other @SubscribeEvent (EntityPlayer is not even an event). For your purpose you can use event.entityPlayer.getCurrentEquippedItem == null.

[qpwoeiruty]

Now the problem arises that they can't break blocks when they nothing in their hand but they can say if they had a dirt block. So would I have to specify which blocks can be used with which tools? As in if the block they are mining equals stone and if they have a diamond pickaxe, allow them to break it.

[larsgerrits]

You can use the ForgeHooks.isToolEffective method to check if the tool is effective for that block, and if it is, don't cancel it, but if it isn't, then cancel it.

[qpwoeiruty]

Great thanks, but I don't really understand what to put in the parameters as it asks for (stack, block, metadata) and I thought it was just going to be like true or false.

[larsgerrits]

Ok, the first parameter, stack, is the stack the player is currently using for mining the block. the second parameter, block is the block being broken, you get that passed in via the event, and the same goes for metadate, you get that passed in via the event.

[qpwoeiruty]

So I should just leave it as (new ItemStack(Items.diamond_axe), block, metadata) ?

[larsgerrits]

No, you need to do it this way:

if(!ForgeHoos.isToolEffective(event.entityPlayer.getCurrentEquippedItem(),event.block,event.metadata))
{
     event.setCanceled(true);
}

Please don't copy paste, but try to figure out what i did, so you can learn from it.

[qpwoeiruty]

Ahhh that makes a lot more sense, I have mine set up in the opposite way so that it sets it to false if the tool is effective.

[larsgerrits]

Look at what i did, i added a not sign (the thingy on the same key as the number, forget how to call it in english), before the ForgeHook.isToolEffective() call so if the was NOT effective, it would cancel it.

[qpwoeiruty]

Hahaha yeah, both are working, but I am now getting a crash when I try and break a block with my fist but everything else works great. I believe it may have something to do with this error...

 

FML has detected a mod that is using a package name based on 'net.minecraft.src' : net.minecraft.src.FMLRenderAccessLibrary. This is generally a severe programming error.  There should be no mod code in the minecraft namespace. MOVE YOUR MOD! If you're in eclipse, select your source code and 'refactor' it into a new package. Go on. DO IT NOW!

 

...which sounds fairly bad, however I don't believe I am using a package based on 'net.minecraft.src' so I am confused.

 

Edit: Actually I don't think it does as when I remover the MinecraftForge.EVENT_BUS.register(new WSPEventHandler()); everything works fine, so I now I believe it is something to do with this line:

 

if(ForgeHooks.isToolEffective(event.entityPlayer.getCurrentEquippedItem(), event.block, event.metadata)) {

 

Its within this class:

 

package com.willr27survivalplus.handler;

 

import net.minecraft.block.Block;

import net.minecraft.entity.player.EntityPlayer;

import net.minecraft.init.Blocks;

import net.minecraft.init.Items;

import net.minecraft.item.ItemStack;

import net.minecraftforge.common.ForgeHooks;

import net.minecraftforge.event.entity.player.PlayerEvent;

import net.minecraftforge.event.world.BlockEvent;

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

 

public class WSPEventHandler {

 

@SubscribeEvent

public void setBreakSpeed(PlayerEvent.BreakSpeed event) {

 

if(ForgeHooks.isToolEffective(event.entityPlayer.getCurrentEquippedItem(), event.block, event.metadata)) {

 

event.setCanceled(true);

 

} else {

 

event.setCanceled(false);

 

}

 

}

 

}

 

[TheGreyGhost]

Hi

 

If you're getting a crash, post the crash log?

 

I'm guessing it's probably a NullPointerException, and it's probably caused by this

event.entityPlayer.getCurrentEquippedItem()

If the player isn't holding anything, it will be null.

 

-TGG

 

 

[qpwoeiruty]

This link should work:

 

https://gist.github.com/anonymous/954c3004b1a82d000210

[TheGreyGhost]

This link should work:

 

https://gist.github.com/anonymous/954c3004b1a82d000210

 

FYI, what I do when I get an error like this:

 

java.lang.NullPointerException: Unexpected error
at net.minecraftforge.common.ForgeHooks.isToolEffective(ForgeHooks.java:131)

Looking at ForgeHooks.java:131

    public static boolean isToolEffective(ItemStack stack, Block block, int metadata)
    {
        List toolClass = toolClasses.get(stack.getItem());          // NPE here
        return toolClass != null && toolEffectiveness.contains(Arrays.asList(block, metadata, toolClass.get(0)));
    }

 

Not sure what a NullPointerException is? 

Google ->

http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it

 

So that means that I am using an object which is null.  There are only two on this line - stack and toolClasses.  Since stack is being provided by my code when it calls this method, it's a good guess that stack is null.

Why is it null?

It was called at com.willr27survivalplus.handler.WSPEventHandler.setBreakSpeed(WSPEventHandler.java:18)

      if(ForgeHooks.isToolEffective(event.entityPlayer.getCurrentEquippedItem(), event.block, event.metadata)) {

and that means that

event.entityPlayer.getCurrentEquippedItem()

returned null.

 

Why did it return null?  Well the name is a strong clue, because the crash only happens when you're not holding anything.

 

-TGG

 

 

[qpwoeiruty]

Thanks for the very detailed explanation, I understand far better what a NullPointerException is now, however, how to fix it is still quite confusing as I am trying to take in a lot of new information at once. Would have to somewhere say that getCurrentEquippedItem() != null then, or have I misunderstood?

[coolAlias]

Basically what that means is you can't use the isToolEffective method when the player is not holding anything, because it expects an ItemStack, not a null pointer; so, if the player is not holding anything, or the currently held item is not effective against the current block, then cancel the event.

 

Translating the above statement into pseudocode:

if (currentItem == null || isToolEffective(currentItem, etc.)) { cancelEvent; }

[qpwoeiruty]

I can't thank you all enough, this has been bugging me for a while and to finally get to a stage where the basics actually work is fantastic. Is there a simpler way than listing every single block to only have select blocks able to be broken, as I could just list every block but it would be very inefficient.

 

Edit: This does work (just listing all the blocks I want) so it is technically solved but anyone with any better ideas feel free to post them.