Creating a batteryitem with energyvalue?

[ItsAMysteriousYT]

I wanna creat a batteryitem that gets empty after a while when in use(equipped in a specific TileEntity OR Item). How can i save the current energyvalue and where do i have to update it? There is a method called onUpdate i think - anything i have to do special in there e.g only update server/clientSide any packethandling stuff or just changing the energyvalue?

[Cerandior]

A NBTTagCompund should work i think. You can update the values while your machine works.

[ItsAMysteriousYT]

Okay - im doing this right now - is this right?

package itsamysterious.mods.reallifemod.core.items;

import net.minecraft.entity.Entity;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.world.World;
import net.minecraftforge.fml.common.registry.GameRegistry;

public class ItemBattery extends Item{
private float voltage;

public ItemBattery() {
	this.voltage=100;
	setUnlocalizedName("itemBattery");
	GameRegistry.registerItem(this, getUnlocalizedName().substring(5));

}

@Override
public void onUpdate(ItemStack stack, World worldIn, Entity entityIn, int itemSlot, boolean isSelected) {
	super.onUpdate(stack, worldIn, entityIn, itemSlot, isSelected);
	NBTTagCompound batteryTag = new NBTTagCompound();
	batteryTag.setFloat("Voltage", voltage);
	stack.writeToNBT(batteryTag);
}

    public boolean updateItemStackNBT(NBTTagCompound nbt)
    {
    	NBTTagCompound batteryTag = nbt.getCompoundTag("BatteryTag");
    	this.voltage=batteryTag.getFloat("Voltage");
        return true;
    }

}

[Cerandior]

I dont think you are doing this right. You are creating a new tag each tick which will overwrite the previous data.

[ItsAMysteriousYT]

I dont think you are doing this right. You are creating a new tag each tick which will overwrite the previous data.

Okay - ill add a check then if the stack holds a tag already.

[ItsAMysteriousYT]

Better?

@Override
public void onUpdate(ItemStack stack, World worldIn, Entity entityIn, int itemSlot, boolean isSelected) {
	super.onUpdate(stack, worldIn, entityIn, itemSlot, isSelected);
	if(!stack.hasTagCompound()){
		NBTTagCompound batteryTag = new NBTTagCompound();
		batteryTag.setFloat("Voltage", voltage);
		stack.writeToNBT(batteryTag);
	}else
	{
		NBTTagCompound batteryTag = stack.getTagCompound();
		batteryTag.setFloat("Voltage", voltage);
		stack.writeToNBT(batteryTag);
	}
}

[ItsAMysteriousYT]

Oh - true, i tried that once, where else should i store it? IEEP would make sense here i think.

[ItsAMysteriousYT]

So i just have to get the value change it and saveit back all in the NBT? Okay, strange that minecraft hasn't got a better way yet.

[Cerandior]

NBT is good enough. You dont need a better way. Minecraft also created the advanced metadata a.k.a tileentity but that isnt necassary for you in this one.

[ItsAMysteriousYT]

Yes, NBT is just how this works.

@Cerandior: TileEntities are for Blocks. This is an item.

For the updating procedure, do i just call onUpdate in my TileEntity then or do i have to make that out of the itemStack somehow so it does not forcecrash the game?

[Cerandior]

You use nbt to create your voltage. You only want to get rid of your energy while your machine is working. What i mean is that you probably have used a boolean in your machine which will hold the state of your machine. If your machine is working then each tick you want to get out 1 energy unit from your battery. Thats an exmaple. I am sorry that i cant write you a piece of code because i moved to another apartment and my computer is packed. Cant write code from my phone. Try watching an example on guthub.

[ItsAMysteriousYT]

Nono, its okay, just was wondering about where i had to update it Thanks!