java - 无法从 1 个单项中减去？

Question

我已经设置了这种方法，玩家可以在右键单击隐身几秒钟时使用火药，并且将从他们的库存中减去 1 火药。问题是，当他们只剩下 1 个火药时，它不会被减去，因此他们将拥有无限的斗篷。这是我的代码:

if (e.getAction().equals(Action.RIGHT_CLICK_AIR)
        || e.getAction().equals(Action.RIGHT_CLICK_BLOCK)) {
    if (e.getPlayer().getInventory().getItemInHand().getType()
            .equals(Material.SULPHUR)) {
        Player player = e.getPlayer();

        Location location = e.getPlayer().getLocation().add(new Vector(0, 2, 0));

        Bukkit.getWorld(e.getPlayer().getWorld().getName())
                .createExplosion(location, 0);

        player.addPotionEffect(new PotionEffect(PotionEffectType.INVISIBILITY, 80, 0));

        player.getItemInHand().setAmount(player.getItemInHand().getAmount() - 1);
    }
}

Answer 1

我觉得问题就出在这里

player.getItemInHand().setAmount(player.getItemInHand().getAmount() - 1);

ItemStack.setAmount(0) 将失败。

---

检查您的整个算法。

ItemStack hand = player.getItemInHand();
int amount = hand.getAmount();
if (amount > 1) {
    hand.setAmount(amount - 1);
    player.setItemInHand(hand);
} else {
    player.setItemInHand(new ItemStack(Material.AIR));
}