Hello everyone. I am making a block which can change its texture to that of some other block's. I use a TileEntity to store the metadata and the ID of the block of which I am showing the texture. The problem is that writeToNBT and readFromNBT methods are not called (checked using System.out.println). Here's the code of TileEntityCoolBlock.java

package net.net23.aregsroom.mc.lotostuff.entities.tile;

import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.network.NetworkManager;
import net.minecraft.network.Packet;
import net.minecraft.network.play.server.S35PacketUpdateTileEntity;
import net.minecraft.tileentity.TileEntity;

/**
* Created by DeLL on 10/09/2016.
*/
public class TileEntityCoolBlock extends TileEntity{

    public int b = 4;
    public int meta = 0;

    public TileEntityCoolBlock() {
    }

    @Override
    public Packet getDescriptionPacket() {
        NBTTagCompound tag = new NBTTagCompound();
        this.writeToNBT(tag);
        return new S35PacketUpdateTileEntity(xCoord, yCoord, zCoord, 1, tag);
    }

    @Override
    public void onDataPacket(NetworkManager net, S35PacketUpdateTileEntity packet) {
        readFromNBT(packet.func_148857_g());
    }

    @Override
    public void readFromNBT(NBTTagCompound nbt) {
        meta = nbt.getInteger("meta");
        b = nbt.getInteger("id");
    }
    @Override
    public void writeToNBT(NBTTagCompound nbt) {
        nbt.setInteger("id",b);
        nbt.setInteger("meta",meta);
        System.out.println(nbt);
    }

}

And CoolBlock.java

package net.net23.aregsroom.mc.lotostuff.tools.coolblock;

import cpw.mods.fml.common.registry.GameRegistry;
import net.minecraft.block.Block;
import net.minecraft.block.ITileEntityProvider;
import net.minecraft.block.material.Material;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.tileentity.TileEntity;
import net.minecraft.util.IIcon;
import net.minecraft.world.IBlockAccess;
import net.minecraft.world.World;
import net.net23.aregsroom.mc.lotostuff.entities.tile.TileEntityCoolBlock;

import static net.net23.aregsroom.mc.lotostuff.Constants.tabMetal;

/**
* Created by DeLL on 04/09/2016.
*/
public class CoolBlock extends Block implements ITileEntityProvider{

    public CoolBlock() {
        super(Material.rock);
        setCreativeTab(tabMetal);
        setBlockName("coolblock");
        setHardness(2);
        setHarvestLevel("pickaxe", 2);
        setStepSound(Block.soundTypeMetal);
        setResistance(2);
        setLightOpacity(0);
        setBlockTextureName("ltstf:cool_block");
        GameRegistry.registerBlock(this, getUnlocalizedName().substring(5));
    }

    @Override
    public boolean isOpaqueCube() {
        return false;
    }

    @Override
    public boolean onBlockActivated(World w, int x, int y, int z, EntityPlayer p, int p_149727_6_, float p_149727_7_, float p_149727_8_, float p_149727_9_) {
        if(!w.isRemote) return true;
        if(!(p.inventory.getCurrentItem().getItem() instanceof TextureExtractor)) return false;

        TileEntityCoolBlock b = new TileEntityCoolBlock();
        b.readFromNBT(p.inventory.getCurrentItem().getTagCompound()); // I can call it this way, and works fine, changes texture, but when I exit the world and enter it again it has the default texture.

        b.markDirty();
        w.setTileEntity(x,y,z,b);
        w.markBlockForUpdate(x,y,z);

        return true;
    }

    @Override
    public IIcon getIcon(IBlockAccess p, int x, int y, int z, int side) {
        TileEntityCoolBlock tecb = (TileEntityCoolBlock) p.getTileEntity(x,y,z);
        return Block.getBlockById(tecb.b).getIcon(side,tecb.meta);
    }
    @Override
    public TileEntity createNewTileEntity(World p_149915_1_, int p_149915_2_) {
        return new TileEntityCoolBlock();
    }
}

And I registered the tileentity like so:

GameRegistry.registerTileEntity(TileEntityCoolBlock.class, "ltstf-tileentity_coolblock");

in my preInit method. Any help would be really appreciated.

Your TileEntity's NBT methods aren't calling super, ergo there is some data loss (the TE's position in the world), and rather than try and recover what it can (because it doesn't know where it goes), Minecraft just creates a new one.

Your TileEntity's NBT methods aren't calling super, ergo there is some data loss (the TE's position in the world), and rather than try and recover what it can (because it doesn't know where it goes), Minecraft just creates a new one.

You mean This?

 @Override
    public void readFromNBT(NBTTagCompound nbt) {
        super.readFromNBT(nbt);
        meta = nbt.getInteger("meta");
        b = nbt.getInteger("id");
    }
    @Override
    public void writeToNBT(NBTTagCompound nbt) {
        super.writeToNBT(nbt);
        nbt.setInteger("id",b);
        nbt.setInteger("meta",meta);
    }

Doesn't seem to work. Still not getting called