Exp-Bar

Is there a way I can set the XP/Level of a player?

Yes add new data packet but i don't know where can you find packet ID

Not yet, I think. I believe this hasn't been implemented into PocketMine yet. Feel free to correct me if I'm wrong.

PHP:

    public static function calculateLevelInfo($xp) {

        if ($xp instanceof Player){
            $xp = self::getXP($xp);
        }
     
        $level = ($xpneededforlevel = 0);
        $remainingxp = $xp;

        while (true) {
            if ($level >= 30) {
                $xpneededforlevel = 62 + ($level - 30) * 7;
            } elseif ($level >= 15) {
                $xpneededforlevel = 17 + ($level - 15) * 3;
            } else {
                $xpneededforlevel = 17;
            }

            if ($xpneededforlevel > $remainingxp) {
                break;
            } else {
                $level++;
                $remainingxp = $remainingxp - $xpneededforlevel;
            }
        }

        return array(
            "level" => $level,
            "remainingxp" => $remainingxp,
            "xpnextlevel" => $xpneededforlevel,
        );

@ Source Tschrok

way to create a way of levels

You used the code from @tschrock. At least give him credit...

ah xD it can be dragged from one year on my keyboard.

That doesn't do anything to the client.

So how can we find out info about packet?

Decompile libminecraftpe.so in the MCPE APK file and read the contents yourself. You can try using PocketBurger https://github.com/PocketMine/PocketBurger although it may be outdated.