Does not work in the preservation of NBT, now explain all the details.

There is a block, he tileentity. In tileentity string with the name of the block.

When you activate the unit GUI opens to the input field, I enter the name of the block, it should be maintained.

GUI:

private TileEntityBlock entityBlock;
...
public GuiBlock (InventoryPlayer inventoryPlayer, TileEntityBlock tileEntity) {
            super (new ContainerTiny (inventoryPlayer, tileEntity));
            this.entityBlock = tileEntity;
    }
That got a copy tileentity
Now introduce more line
public void keyTyped (char c, int i) {
        if (textfield.textboxKeyTyped (c, i)) {
            entityBlock.name = textfield.getText ();
        }
        else
        {
            super.keyTyped (c, i);
        }
    }

 

Well, then render. The fact that all work in the name of each block but do not conserved.

In TileEntityBlock:

public String name = "";
....
@ Override
    public void writeToNBT (NBTTagCompound nbt) {
            super.writeToNBT (nbt);
                            
            nbt.setString ("name", name);
    }
    
    @ Override
    public void readFromNBT (NBTTagCompound nbt) {
            super.readFromNBT (nbt);
            
            name = nbt.getString ("name");
    }

 

Why does not work?

For example, like a plate, right?

The sign has a packet Packet130UpdateSign I need to do the same, only with another par?

I take it you mean packet and not plate. So yes, you do need a packet.