Solved Trying to remove a block after amount of time being placed.

Hi, in my plugin I'm adding a feature to where players are allowed to place cobwebs down. I want to make it to where after a certain amount of time the cobwebs are removed. Can someone help me?

Code:

    @EventHandler (priority = EventPriority.HIGHEST)
    public void onPlaceCobWeb(BlockPlaceEvent e)
    {
        Material material = e.getBlock().getType();
        Location loc = e.getBlock().getLocation();

       
        if(material == Material.WEB)
        {
            e.setCancelled(false);
           
        }
    }

 

@Calebizzthaman
When a cobweb is placed, schedule a BukkitRunnable to be executed at a later date, and then remove the cobweb inside that runnable.

 

How would I go about doing that in this kind of situation?

 

@Calebizzthaman

Code:java

new BukkitRunnable() {
    @Override
    public void run() {
        // Your code to remove the block
    }
}.runTaskLater(plugin, yourDelay);

 

May I add "yourDelay" is in milliseconds, so for one second you would put:

Code:Java

 
.ranTaskLater(plugin, 1000);
 

for 1 second.

 

@MemeplexOwner
Actually, it's not in milliseconds. It's in gameticks, which are equivalent to twentieths of a second. One second would be '20'.

 

Ah, just checked the docs, and it is game ticks, isn't 20 game ticks 1 second or something? I'm not really too sure.

 

I don't quite understand. Would I place it in my if statement in the listener?

 

@Calebizzthaman
Correct.

 

So, when I try this. It sends me a whole bunch of errors. Here is my code.
Btw: disregard my event "onPlaceMedicineItems"

Code:

public class BlockPlacing implements Listener{
   
    Plugin plugin;
   
    //Stops players from placing items when using medicine items
    @EventHandler
    public void onPlaceMedicineItems(BlockPlaceEvent e)
    {
        Player p = e.getPlayer();
        Material material = e.getBlock().getType();
       
        if(!p.isOp())
        {
            if(material == Material.YELLOW_FLOWER)
            {
                e.setCancelled(true);
            }
        }
    }
   
    @EventHandler (priority = EventPriority.HIGHEST)
    public void onPlaceCobWeb(BlockPlaceEvent e)
    {
        Material material = e.getBlock().getType();


        if(material == Material.WEB)
            {
            e.setCancelled(false);
            e.getPlayer().sendMessage(ChatColor.GREEN + "You placed barbed wire!");

            new BukkitRunnable() {
                @Override
                public void run() {
                    e.getBlock().setType(Material.AIR);
                }
            }.runTaskLater(plugin, 60);
           
            }
        }
 }

 

@Calebizzthaman
And what error do you get?

 

It says Plugin cannot = null but, it doesn't...

@AlvinB

[10:25:25 ERROR]: Could not pass event BlockPlaceEvent to ZombieApocalypse v1.0
org.bukkit.event.EventException: null
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:499) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:484) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.craftbukkit.v1_12_R1.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:149) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.ItemStack.placeItem(ItemStack.java:207) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.PlayerInteractManager.a(PlayerInteractManager.java:495) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.PlayerConnection.a(PlayerConnection.java:944) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.PacketPlayInUseItem.a(PacketPlayInUseItem.java:37) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.PacketPlayInUseItem.a(PacketPlayInUseItem.java:1) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_131]
at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_131]
at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:46) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:747) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:405) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:678) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:576) [spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_131]
Caused by: java.lang.IllegalArgumentException: Plugin cannot be null
at org.apache.commons.lang.Validate.notNull(Validate.java:192) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftScheduler.validate(CraftScheduler.java:400) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftScheduler.runTaskTimer(CraftScheduler.java:126) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftScheduler.runTaskLater(CraftScheduler.java:109) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at org.bukkit.scheduler.BukkitRunnable.runTaskLater(BukkitRunnable.java:64) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
at me.aniketus.playerdeathzombiespawn.BlockPlacing.onPlaceCobWeb(BlockPlacing.java:51) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_131]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_131]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_131]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_131]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot-1.12.jar:git-Spigot-cd6ba67-a7d074c]
... 18 more

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

@Calebizzthaman
Well, you never set the plugin field to anything, making it be null. Set the field to the instance of your main class, and it should work.

 

@AlvinB Sorry, I know I'm asking a lot. I've just got back into coding with Java and Bukkit recently. Could you give me an example on how to do that?

 

@Calebizzthaman
Create a constructor for the Listener which takes the plugin instance as an argument, and set the field equal to this argument.

 

@AlvinB

Code:

    private static Plugin instance;

?

 

@Calebizzthaman
No, don't use static.

Create a constructor that takes the plugin instance and set 'instance' equal to it.

Code:java

public MyClass(Plugin plugin) {
    this.instance = plugin;
}

Your Java skills seem to be a little too rusty for your own good. If I were you, I'd go back and revisit some of the tutorials.

 

You're correct. I'm gonna do that! Thanks a lot for the help! It's working now.