[1.11] Spawning Items When Block Is Broken

[Lambda]

Hey there,

 

So I'm in need of dropping an item when a block is broken, I have the event but i need to spawn the item in.

[EscapeMC]

Do you want this item to always drop? Or have a random chance from breaking this block?

[Lambda]

Random chance, but know how to handle that

[Lambda]

How would I override an event like that? one of the first times messing with them.

[larsgerrits]

For your own blocks: override

getDrops

.

 

For other mods/Minecraft's blocks: use the

HarvestDrops

event.

[Lambda]

Yes like this:

    @SubscribeEvent
    public static void HarvestDropsEvent(BlockEvent.HarvestDropsEvent event) {
        Minecraft mc = Minecraft.getMinecraft();
        if(event.getHarvester() instanceof EntityPlayer) {
            if(!event.isSilkTouching()) {
                if(event.getDrops() == Blocks.COBBLESTONE) {
                    
                }
            }
        }
    }

 

So when cobble is dropped I want it to drop the cobble and x

[Draco18s]

event.getDrops().add(...)

 

Seriously, look at the event object and see what's there.

[Lambda]

Oh, Yeah figured that out before you commented. Thanks either way...

[Lambda]

Okay this:

                if(event.getDrops() == Blocks.COBBLESTONE) {
                    event.getDrops().add(new ItemStack(InitBlocks.block_fire_opal_ore));
                }

seems not to drop when a block drops cobblestone (ex. stone), and also, is there a way to find the block that I'm mining, other than finding the drop?

[Lambda]

ah yes, so look for a ItemStack like this?

        if(event.getHarvester() instanceof EntityPlayer) {
            if(!event.isSilkTouching()) {
                if(event.getDrops().contains(new ItemStack(Blocks.COBBLESTONE))) {
                    event.getDrops().add(new ItemStack(InitBlocks.block_fire_opal_ore));
                }
            }
        }

However, still doesnt seem to drop

[Draco18s]

You can't use

contains

in this context.  ItemStack does not override

equals

so it will never find a match.

[Lambda]

Then how would I do it, I tried making a list and comparing the list, however didnt seem to work:/

[Draco18s]

for(ItemStack stack : event.getDrops()) { //loop over everyting
  if(stack.getItem() == Item.getItemFromBlock(Blocks.COBBLESTONE)) { //check if each item is cobblestone
  }
}

[Lambda]

Thanks! However, the random chance thing seems to drop nothing, not even the cobble:

   if (event.getHarvester() instanceof EntityPlayer) {
            if (!event.isSilkTouching()) {
                for(ItemStack stack : event.getDrops()) {
                    if(stack.getItem() == Item.getItemFromBlock(Blocks.COBBLESTONE)) {
                        if(rand.nextInt(2) == 1) {
                            event.getDrops().add(new ItemStack(InitItems.item_gems, 1, 0));
                            event.getDrops().add(new ItemStack(InitItems.item_gems, 1, 1));
                            event.getDrops().add(new ItemStack(InitItems.item_gems, 1, 2));
                            event.getDrops().add(new ItemStack(InitItems.item_gems, 1, 3));
                            event.getDrops().add(new ItemStack(Blocks.COBBLESTONE, 1));
                        }
                        event.getDrops().add(new ItemStack(Blocks.COBBLESTONE, 1));
                    }
                }
            }
        }

[Draco18s]

By "not even the cobble" you mean that you're not getting two cobble stone (the statement outside the if(rand) statement)?

[Lambda]

No I added the second one because cobble wasnt even dropping when I added the rand. Even if the rand was false.

[Draco18s]

Assign it to a variable and print it out or use the debugger to figure out what value is coming out of it every time.

Odds are you've messed up initializing your random object.

[Lambda]

Okay, So I seem to be getting this error:

[22:05:00] [server thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.util.ConcurrentModificationException
at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_91]
at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_91]
at net.minecraft.util.Util.runTask(Util.java:27) [util.class:?]
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:753) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:698) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:156) [integratedServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:547) [MinecraftServer.class:?]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_91]
Caused by: java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901) ~[?:1.8.0_91]
at java.util.ArrayList$Itr.next(ArrayList.java:851) ~[?:1.8.0_91]
at com.lambda.plentifulmisc.events.CommonEvents.HarvestDropsEvent(CommonEvents.java:83) ~[CommonEvents.class:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_12_CommonEvents_HarvestDropsEvent_HarvestDropsEvent.invoke(.dynamic) ~[?:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) ~[ASMEventHandler.class:?]
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:185) ~[EventBus.class:?]
at net.minecraftforge.event.ForgeEventFactory.fireBlockHarvesting(ForgeEventFactory.java:260) ~[ForgeEventFactory.class:?]
at net.minecraft.block.Block.dropBlockAsItemWithChance(Block.java:692) ~[block.class:?]
at net.minecraft.block.Block.dropBlockAsItem(Block.java:681) ~[block.class:?]
at net.minecraft.block.Block.harvestBlock(Block.java:889) ~[block.class:?]
at net.minecraft.server.management.PlayerInteractionManager.tryHarvestBlock(PlayerInteractionManager.java:355) ~[PlayerInteractionManager.class:?]
at net.minecraft.server.management.PlayerInteractionManager.blockRemoving(PlayerInteractionManager.java:264) ~[PlayerInteractionManager.class:?]
at net.minecraft.network.NetHandlerPlayServer.processPlayerDigging(NetHandlerPlayServer.java:664) ~[NetHandlerPlayServer.class:?]
at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:56) ~[CPacketPlayerDigging.class:?]
at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:12) ~[CPacketPlayerDigging.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:15) ~[PacketThreadUtil$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_91]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_91]
at net.minecraft.util.Util.runTask(Util.java:26) ~[util.class:?]
... 5 more
[22:05:01] [server thread/ERROR]: Exception caught during firing event net.minecraftforge.event.world.BlockEvent$HarvestDropsEvent@2ae16890:
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901) ~[?:1.8.0_91]
at java.util.ArrayList$Itr.next(ArrayList.java:851) ~[?:1.8.0_91]
at com.lambda.plentifulmisc.events.CommonEvents.HarvestDropsEvent(CommonEvents.java:83) ~[CommonEvents.class:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_12_CommonEvents_HarvestDropsEvent_HarvestDropsEvent.invoke(.dynamic) ~[?:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) ~[ASMEventHandler.class:?]
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:185) [EventBus.class:?]
at net.minecraftforge.event.ForgeEventFactory.fireBlockHarvesting(ForgeEventFactory.java:260) [ForgeEventFactory.class:?]
at net.minecraft.block.Block.dropBlockAsItemWithChance(Block.java:692) [block.class:?]
at net.minecraft.block.Block.dropBlockAsItem(Block.java:681) [block.class:?]
at net.minecraft.block.Block.harvestBlock(Block.java:889) [block.class:?]
at net.minecraft.server.management.PlayerInteractionManager.tryHarvestBlock(PlayerInteractionManager.java:355) [PlayerInteractionManager.class:?]
at net.minecraft.server.management.PlayerInteractionManager.blockRemoving(PlayerInteractionManager.java:264) [PlayerInteractionManager.class:?]
at net.minecraft.network.NetHandlerPlayServer.processPlayerDigging(NetHandlerPlayServer.java:664) [NetHandlerPlayServer.class:?]
at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:56) [CPacketPlayerDigging.class:?]
at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:12) [CPacketPlayerDigging.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:15) [PacketThreadUtil$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_91]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_91]
at net.minecraft.util.Util.runTask(Util.java:26) [util.class:?]
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:753) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:698) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:156) [integratedServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:547) [MinecraftServer.class:?]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_91]
[22:05:01] [server thread/ERROR]: Index: 1 Listeners:
[22:05:01] [server thread/ERROR]: 0: NORMAL
[22:05:01] [server thread/ERROR]: 1: ASM: class com.lambda.plentifulmisc.events.CommonEvents HarvestDropsEvent(Lnet/minecraftforge/event/world/BlockEvent$HarvestDropsEvent;)V
[22:05:01] [server thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.util.ConcurrentModificationException
at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_91]
at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_91]
at net.minecraft.util.Util.runTask(Util.java:27) [util.class:?]
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:753) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:698) [MinecraftServer.class:?]
at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:156) [integratedServer.class:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:547) [MinecraftServer.class:?]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_91]
Caused by: java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901) ~[?:1.8.0_91]
at java.util.ArrayList$Itr.next(ArrayList.java:851) ~[?:1.8.0_91]
at com.lambda.plentifulmisc.events.CommonEvents.HarvestDropsEvent(CommonEvents.java:83) ~[CommonEvents.class:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_12_CommonEvents_HarvestDropsEvent_HarvestDropsEvent.invoke(.dynamic) ~[?:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) ~[ASMEventHandler.class:?]
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:185) ~[EventBus.class:?]
at net.minecraftforge.event.ForgeEventFactory.fireBlockHarvesting(ForgeEventFactory.java:260) ~[ForgeEventFactory.class:?]
at net.minecraft.block.Block.dropBlockAsItemWithChance(Block.java:692) ~[block.class:?]
at net.minecraft.block.Block.dropBlockAsItem(Block.java:681) ~[block.class:?]
at net.minecraft.block.Block.harvestBlock(Block.java:889) ~[block.class:?]
at net.minecraft.server.management.PlayerInteractionManager.tryHarvestBlock(PlayerInteractionManager.java:355) ~[PlayerInteractionManager.class:?]
at net.minecraft.server.management.PlayerInteractionManager.blockRemoving(PlayerInteractionManager.java:264) ~[PlayerInteractionManager.class:?]
at net.minecraft.network.NetHandlerPlayServer.processPlayerDigging(NetHandlerPlayServer.java:664) ~[NetHandlerPlayServer.class:?]
at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:56) ~[CPacketPlayerDigging.class:?]
at net.minecraft.network.play.client.CPacketPlayerDigging.processPacket(CPacketPlayerDigging.java:12) ~[CPacketPlayerDigging.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(PacketThreadUtil.java:15) ~[PacketThreadUtil$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_91]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_91]
at net.minecraft.util.Util.runTask(Util.java:26) ~[util.class:?]
... 5 more

 

On line:

                for(ItemStack stack : event.getDrops()) {

 

This, however doesnt crash my game.

[MFMods]

you can not modify a collection while you are iterating over it.

make a local boolean variable hasStoneOrWhatever and fill it if you find whatever. then, outside the loop, use it to decide how to edit the list of item stacks.

[Lambda]

Thanks! That seemed to fix it!