So...

I have one problem.

It is that while i am playing the nbt data is temporary saved, but when i exit it's deleted and i dont know why!

If you could help me that would be nice.

Here is the source: https://www.dropbox.com/sh/7pj70z3mbbdde38/BAz6Zvq7Gw

Thank you!

I'm not an expert on NBT usage, but the only way I've ever used it to save Entity specific data is within the entities class methods read/writeEntityToNBT( nbt ). Also, it doesn't work on the client side. Forgive me if you understood this already, but in my example I use it like this in the class that stands for the entity's data you wish to save and recall.

 

 

I have updated it to show the full code of the Entity:

package gff.companime.entity.companions;

import java.util.Random;

import gff.companime.Companime;
import net.minecraft.client.Minecraft;
import net.minecraft.entity.DataWatcher;
import net.minecraft.entity.EntityAgeable;
import net.minecraft.entity.EntityLiving;
import net.minecraft.entity.ai.EntityAIAvoidEntity;
import net.minecraft.entity.ai.EntityAIFollowGolem;
import net.minecraft.entity.ai.EntityAILookAtTradePlayer;
import net.minecraft.entity.ai.EntityAIMoveIndoors;
import net.minecraft.entity.ai.EntityAIMoveTwardsRestriction;
import net.minecraft.entity.ai.EntityAIOpenDoor;
import net.minecraft.entity.ai.EntityAIPlay;
import net.minecraft.entity.ai.EntityAIRestrictOpenDoor;
import net.minecraft.entity.ai.EntityAISwimming;
import net.minecraft.entity.ai.EntityAITempt;
import net.minecraft.entity.ai.EntityAITradePlayer;
import net.minecraft.entity.ai.EntityAIVillagerMate;
import net.minecraft.entity.ai.EntityAIWander;
import net.minecraft.entity.ai.EntityAIWatchClosest;
import net.minecraft.entity.ai.EntityAIWatchClosest2;
import net.minecraft.entity.monster.EntityZombie;
import net.minecraft.entity.passive.EntityVillager;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.world.World;

public class EntityGal extends EntityAgeable
{
public int haircolor;

public EntityGal(World par1World)
    {
        super(par1World);
        this.texture = "/textures/mob/gal/gal.png";
        this.moveSpeed = 0.5F;
        this.setSize(0.6F, 1.8F);
        this.getNavigator().setBreakDoors(true);
        this.getNavigator().setAvoidsWater(true);
        // AI tasks for the entity to perform
        this.tasks.addTask(0, new EntityAISwimming(this));
        this.tasks.addTask(1, new EntityAITempt(this, 0.3F, Companime.braceletItem.itemID, false));
        this.tasks.addTask(2, new EntityAIMoveIndoors(this));        
        this.tasks.addTask(3, new EntityAIOpenDoor(this, true));
        this.tasks.addTask(4, new EntityAIMoveTwardsRestriction(this, 0.3F));
        this.tasks.addTask(5, new EntityAIWatchClosest2(this, EntityPlayer.class, 3.0F, 1.0F));
        this.tasks.addTask(5, new EntityAIWatchClosest2(this, EntityGal.class, 5.0F, 0.02F));
        this.tasks.addTask(5, new EntityAIWander(this, 0.3F));
        this.tasks.addTask(6, new EntityAIWatchClosest(this, EntityGal.class, 8.0F));
        
        // Generate instance specific data
        Random rnd = new Random();
        this.setHairColor(rnd.nextInt(0xffffff));
        this.haircolor = this.getHairColor();
    }

    public void entityInit()
    {
        super.entityInit();
        // Create a data watcher for hair color
        this.dataWatcher.addObject(20, Integer.valueOf(0));
        
    }

// writes persistent values that is saved to the world server side
    public void writeEntityToNBT(NBTTagCompound nbt)
    {
    	super.writeEntityToNBT(nbt);
    	
    	nbt.setInteger("haircolor", this.getHairColor());  	        	    	
    }
    
// reads a persistant value from the server's world
    public void readEntityFromNBT(NBTTagCompound nbt)
    {
    	super.readEntityFromNBT(nbt);
    	
    	this.setHairColor(nbt.getInteger("haircolor"));        	    	       
    }   
    
    // This function will set an RGB color
    // It is called later with EntityGal.getHairColor() in the renderer
    public void setHairColor(int color)
    {
        this.dataWatcher.updateObject(20, Integer.valueOf(color));
    }
    
    // Returns the value set by setHairColor as "haircolor" in the Entities NBTTagCompound
    public int getHairColor()
    {
        return this.dataWatcher.getWatchableObjectInt(20);
    }
    
@Override
public EntityAgeable createChild(EntityAgeable entityageable) {
	// TODO Auto-generated method stub
	return null;
}

@Override
public int getMaxHealth() {
	// TODO Auto-generated method stub
	return 10;
}

public boolean interact(EntityPlayer par1EntityPlayer)
    {
        ItemStack itemstack = par1EntityPlayer.inventory.getCurrentItem();
        
        System.out.println(this.worldObj);
        System.out.println("ID: "+this.entityId);
        System.out.println("isRemote = "+this.worldObj.isRemote);
        System.out.println(this.haircolor); // Example of how to get this entity haircolor
        return true;
    }

}

 

so can you tell me how to sync them please

There are a few methods to sync them. My example uses datawatchers. If you are familiar with java you should be able to grok with my example.