我目前正在学习预定的任务。
基本上，我制作了一个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，任务取消似乎不会执行。
主要课程：
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;
}
}
听众课程：
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);
}
}
答案 0 :(得分：2)
没有必要取消任务，因为它已经结束了。我在您的代码中看到了一些问题。第一个也可能是最严重的是你在PlayerMoveEvent中安排一个任务，而不仅仅是那个，但它也是不必要的。使用该事件时，您应始终非常小心。每当玩家移动任何东西时都会调用它，包括他们的头部。因此，该事件每秒可被称为数百次或事件数千次。如果不是绝对必要，您应该始终进行检查，确保玩家移动到新的块以降低代码运行的次数。一个更简单的方法就是做这样的事情：
@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);
}
}
还要知道，只有在滴答声过去后才会调用您的调度程序，并且程序的其余部分将继续。您可以检查播放器是否已在调度程序中移动
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);
另外还有一个简单说明：每次更改其值时，都不需要从HashMap中删除播放器。 HashMap.put（）将覆盖现有值。
编辑（另一个建议）： 这可能是做到这一点的最好方法，如果你希望在移动后立即实现向播放器发送取消消息的效果，你可以从playerMoves方法中取消调度程序，而不是将播放器添加到HashMap。这样，甚至不需要HashMap，它只会提高整体代码质量。你真的应该尽量避免使用HashMaps，这通常是一种更好的做事方式。