i looked source code from some mods that store player xp, to remove it they use this method from OpenMods: https://github.com/OpenMods/OpenModsLib/blob/1.16/src/main/java/openmods/utils/EnchantmentUtils.java

The place i looked at: https://github.com/bl4ckscor3/XP-Tome/blob/1.18/src/main/java/bl4ckscor3/mod/xptome/XPTomeItem.java#L76 (from line 70 to 76)

I copied the class too, and even used both PlayerXpEvents, at first it removes the xp i put but when i kill myself or something is like the xp never leaved me, it is not a "keepinventoryrule" cause im removing the xp from code :b

BTW: in case you need to know, im removing the xp from a screen (client) when i press a button

public class TotisPlayerUtils {
  	private static int sum(int n, int a0, int d) {
        return n * (2 * a0 + (n - 1) * d) / 2;
    }
    private static int xpBarCap(int level) {
        if (level >= 30)
            return 112 + (level - 30) * 9;

        if (level >= 15)
            return 37 + (level - 15) * 5;

        return 7 + level * 2;
    }
    public static int getLevelForExperience(int targetXp) {
        int level = 0;
        while (true) {
            final int xpToNextLevel = xpBarCap(level);
            if (targetXp < xpToNextLevel) return level;
            level++;
            targetXp -= xpToNextLevel;
        }
    }
    public static int getExperienceForLevel(int level) {
        if (level == 0) return 0;
        if (level <= 15) return sum(level, 7, 2);
        if (level <= 30) return 315 + sum(level - 15, 37, 5);
        return 1395 + sum(level - 30, 112, 9);
    }
    public static int getPlayerXP(Player player) {
        return (int)(getExperienceForLevel(player.experienceLevel) + (player.experienceProgress * player.getXpNeededForNextLevel()));
    }

    public static void addPlayerXP(Player player, int amount) {
        int experience = getPlayerXP(player) + amount;
        player.totalExperience = experience;
        player.experienceLevel = getLevelForExperience(experience);
        int expForLevel = getExperienceForLevel(player.experienceLevel);
        player.experienceProgress = (experience - expForLevel) / (float)player.getXpNeededForNextLevel();
    }
}

 

The screen part

int xp = TotisPlayerUtils.getPlayerXP(player);
if(xp >= 1) {
	int depositedXp = 20;
	int previousLevel = player.experienceLevel;
	MinecraftForge.EVENT_BUS.post(new PlayerXpEvent.XpChange(player, -depositedXp));
	TotisPlayerUtils.addPlayerXP(player, -depositedXp); //should remove 20 xp, it does but not permanently
	if(previousLevel != player.experienceLevel) MinecraftForge.EVENT_BUS.post(new PlayerXpEvent.LevelChange(player, player.experienceLevel));
} else {
	player.sendMessage(new TextComponent(ChatFormatting.RED + "Error: no XP to deposit"), player.getUUID());
}

 

32 minutes ago, ElTotisPro50 said:

BTW: in case you need to know, im removing the xp from a screen (client) when i press a button

You cannot remove xp from the client player; it will not sync to the server. You should instead send a packet to the server and remove the experience from the player there. You can set experience points using either `Player#giveExperiencePoints` or `Player#giveExperienceLevels` or directly through `Player#setExperiencePoints` or `Player#setExperienceLevels`. Additionally, that is not how you listen to an event. I would suggest reading how to do so on the docs.