[1.11.2] How to give item from gui?

[WildHeart]

Hello, i have a gui, that gives things at the click of a button. I know I need to send packets, do so, but the subject is not given.

public class SPacketGiveItem extends AbstractPacket<SPacketGiveItem>
{
    public SPacketGiveItem(){}

    @Override
    public void handleClientSide(EntityPlayer player) {

    }

    @Override
    public void handleServerSide(EntityPlayerMP player)
    {
        player.inventory.addItemStackToInventory(new ItemStack(Items.apple));
    }

    @Override
    public void fromBytes(ByteBuf buf)
    {

    }

    @Override
    public void toBytes(ByteBuf buf)
    {

    }
}

What could be wrong?

[WildHeart]

Solved, my fail...