can smbdy help me?

PHP:

public function queue(Player $player)
    {
        if (empty($this->alr[$player->getUniqueId()->toString()])) {
            $this->queue[] = $player->getName();
            $this->alr[$player->getUniqueId()->toString()] = true;
        }
    }

PHP:

public function onInteract(PlayerInteractEvent $event) {
        $player = $event->getPlayer();
        $inst = ItemFactory::getInstance();
        $it = VanillaItems::DIAMOND();
        $form = new SimpleForm(function (Player $player, int $data = null){
            $result = $data;
            if($result === null){ // Closed form without submitting
                return;
            }
            switch($result){
                case 0:
                    $this->queue($player);
                    if (count($this->queue) == 2) {
                        $arr = array_shift($this->queue);
                        $player1 = $this->getServer()->getPlayerExact($this->queue[0]);
                        $player2 = $this->getServer()->getPlayerExact($this->queue[1]);
                        if ($player1 instanceof Player || $player2 instanceof Player) {
                            $player2->sendMessage("lmao");
                            $player1->sendMessage("zzz");
                        }
                    }
                    print_r(count($this->queue));
                    $player->sendMessage("a");
                    print_r($this->queue);
                    break;
            }
        });

        $form->addButton("Duels");
        $form->setTitle("Play");
        if ($event->getItem() == $it) {
            $this->getLogger()->info("worked!");
            $form->sendToPlayer($player);
        }
    }

undefined array key 1 on line 54 ( $player2 = $this->getServer()->getPlayerExact($this->queue[1]); )

 

because you have used `array_shift` the array no longer has 2 keys in it.