当 HashMap 值为真时，任务不会被取消

Question

我目前正在学习计划任务。

基本上，我正在制作一个 Bukkit 插件，您可以在其中启用或禁用 PVP。当玩家输入/pvp on 或 /pvp off 时，他们不能移动 5 秒，但是任务取消似乎没有执行。

主要class:

package me.mortadelle2.pvptoggle;

import java.util.ArrayList;
import java.util.HashMap;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.util.Vector;

public class PVPToggle extends JavaPlugin {

    ArrayList<String> noPVP = new ArrayList<String>();

    HashMap<String, Boolean> hasMoved = new HashMap<String, Boolean>();

    Player p;

    public void onEnable() {

        new PlayerDamage(this);
        getLogger().info("PVPToggle toggled!");

    }

    public void onDisable() {

        getLogger().info("PVPToggle disabled!");

    }

    public boolean onCommand(CommandSender sender, Command cmd, String label,
            String[] args) {

        p = (Player) sender;

        if (cmd.getName().equalsIgnoreCase("pvp")) {

            if (args.length == 0) {

                p.sendMessage(ChatColor.RED + "Invalid usage! /pvp [on or off]");
                return true;

            }

            if (args.length == 1) {

                if (args[0].equalsIgnoreCase("on")) {

                    p.sendMessage(ChatColor.YELLOW
                            + "PVP will be turned on in 5 seconds! Don't move!");
                    hasMoved.remove(p.getName());
                    hasMoved.put(p.getName(), false);

                    int turnOn = this.getServer().getScheduler()
                            .scheduleSyncDelayedTask(this, new Runnable() {

                                @Override
                                public void run() {

                                    if (hasMoved.get(p.getName()) == false) {
                                        noPVP.remove(p.getName());
                                        p.sendMessage(ChatColor.YELLOW
                                                + "You have turned PVP on!");
                                    }

                                }
                            }, 100L);

                    if (hasMoved.get(p.getName()) == true) {
                        p.sendMessage(ChatColor.RED
                                + "You moved so the action was cancelled.");
                        this.getServer().getScheduler().cancelTask(turnOn);
                    }

                    return true;

                }

                if (args[0].equalsIgnoreCase("off")) {

                    p.sendMessage(ChatColor.YELLOW
                            + "PVP will be turned off in 5 seconds. Don't move!");

                    hasMoved.remove(p.getName());
                    hasMoved.put(p.getName(), false);

                    int turnOff = this.getServer().getScheduler()
                            .scheduleSyncDelayedTask(this, new Runnable() {

                                @Override
                                public void run() {

                                    if (hasMoved.get(p.getName()) == false) {
                                        noPVP.add(p.getName());
                                        p.sendMessage(ChatColor.YELLOW
                                                + "You have turned PVP off!");
                                    }

                                }

                            }, 100L);

                    if (hasMoved.get(p.getName()) == true) {
                        p.sendMessage(ChatColor.RED
                                + "You moved so the action was cancelled.");
                        this.getServer().getScheduler().cancelTask(turnOff);
                    }

                    return true;
                }

            }

        }

        return false;
    }

}

听众class:

    package me.mortadelle2.pvptoggle;

import org.bukkit.Bukkit;
import org.bukkit.entity.Arrow;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDamageByEntityEvent;
import org.bukkit.event.entity.EntityShootBowEvent;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.event.player.PlayerMoveEvent;
import org.bukkit.util.Vector;

public class PlayerDamage implements Listener{

    PVPToggle getter;

    public PlayerDamage(PVPToggle plugin) {

        plugin.getServer().getPluginManager().registerEvents(this, plugin);

        this.getter = plugin;

    }

    @EventHandler
    public void playerJoins(PlayerJoinEvent e){

        Player p = e.getPlayer();
        getter.hasMoved.put(p.getName(), false);

    }

    @EventHandler
    public void playerDamages(EntityDamageByEntityEvent e){

        Player victim = (Player) e.getEntity();
        Player killer = (Player) e.getDamager();

        victim.sendMessage("hey");

        if (getter.noPVP.contains(victim.getName()) || getter.noPVP.contains(killer.getName())){
            e.setCancelled(true);
        }

    }

    @EventHandler
    public void playerShootsPlayer(EntityShootBowEvent e){

        Arrow a = (Arrow) e.getEntity();

        Player shooter = (Player) a.getShooter();

        if (getter.noPVP.contains(a.getName()) || getter.noPVP.contains(shooter.getName())){
            e.setCancelled(true);
        }



    }

    @EventHandler
    public void playerMoves(PlayerMoveEvent e) {

        final Player p = e.getPlayer();

        final Vector pVel = p.getVelocity();

        getter.getServer().getScheduler()
                .scheduleSyncDelayedTask(getter, new Runnable() {

                    @Override
                    public void run() {


                        if (pVel.getX() != 0 || pVel.getBlockY() != 0
                                || pVel.getBlockZ() != 0) {
                            getter.hasMoved.remove(p.getName());
                            getter.hasMoved.put(p.getName(), true);
                        } else {
                            getter.hasMoved.remove(p.getName());
                            getter.hasMoved.put(p.getName(), false);
                        }

                    }
                }, 5L);

    }

}

Answer 1

没有必要取消任务，因为它已经结束了。我还发现您的代码存在一些问题。第一个并且可能是最严重的是您在 PlayerMoveEvent 中安排任务，不仅如此，而且它也是不必要的。使用该事件时应始终格外小心。每次玩家移动任何东西（包括他们的头）时都会调用它。因此，该事件每秒可以调用数百次或数千次。如果不是绝对必要，您应该始终进行检查以确保玩家移动到新块以减少您的代码运行的次数。一个更简单的方法是只做这样的事情：

@EventHandler
public void playerMoves(PlayerMoveEvent e) {
    Player p = e.getPlayer();

    //Check if the player moved to a new block
    if (e.getTo().getBlockX() != e.getFrom().getBlockX() || e.getTo().getBlockY() != e.getFrom().getBlockY() || e.getTo().getBlockZ() != e.getFrom().getBlockZ()) {
        //If they have, set their value in the hashmap to true
        getter.hasMoved.put(p.getName(), true);
    }
}

还知道您的调度程序仅在滴答结束时被调用一次，程序的其余部分将继续。您可以在调度程序中检查玩家是否移动

Bukkit.getScheduler().scheduleSyncDelayedTask(this, new Runnable() {

    @Override
    public void run() {

        if (hasMoved.get(p.getName()) == false) {
            noPVP.remove(p.getName());
            p.sendMessage(ChatColor.YELLOW + "You have turned PVP on!");
        } else {
            p.sendMessage(ChatColor.RED + "You moved so the action was cancelled.");
        }
    }
}, 100L);

另请注意：您无需在每次更改播放器的值时都从 HashMap 中删除该播放器。 HashMap.put() 将覆盖现有值。

编辑（另一个建议）：可能是执行此操作的最佳方法，如果您想达到在玩家移动后立即向玩家发送取消消息的效果，您可以从 playerMoves 方法内部取消调度程序，而不是将玩家添加到哈希表。这样甚至不需要 HashMap，它只会提高整体代码质量。您真的应该尽量避免使用 HashMap，通常有更好的方法。

当 HashMap 值为真时，任务不会被取消

Task not being cancelled when HashMap value is true

java

bukkit