Solved PlayerInteractEvent triggering twice?

Hey experts out there,

I got the feeling that PlayerInteractEvent triggers twice. Actually that only happens if no certain action is performed like placing a block or opening a chest.
This is the code I have been testing with, it really couldn't be more simple:

Code:

import org.bukkit.Bukkit;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class Plugin extends JavaPlugin implements Listener {

    @Override
    public void onEnable() {
        Bukkit.getPluginManager().registerEvents(this, this);
    }

    @Override
    public void onDisable() {}

    @EventHandler
    public void interact(PlayerInteractEvent e) {
        e.getPlayer().sendMessage(e.getAction().name());
    }
}

I tested it in 1.12.2 but I am sure that it already bothered me in other versions.
Anyway, I am wondering that I could not find any other threads answering this question or so.

Can any genius answer me why this happens and how I can stop it?
I mean there are plenty work arounds, like keeping track of the time passed between the 2 events (0 ticks). But I would feel more comfortable if there was an actual solution.

Thanls for any help,
MightyOne

 

@MightyOne
The event fires twice because this runs for both of the player's hands.

To force it to only run once, make sure the hand used (Event#getHand()) is the main hand.

 

@Zombie_Striker oh man thanks a lot

Do you know how i coul dget this to work for plugins from 1.8 - 1.12?

 

@MightyOne
The simplest fix for 1.8 would be to do the following:

1. create a boolean. Set it to true. This represents if the event should continue.
2. Create a try/catch block. Let the catch be an "Error|Exception" to be able to catch missing-call errors along with just plain exceptions. This is what will make it compatible with 1.8.
3. Inside the try-block, set the boolean equal to if the hand is equal to the main hand. If it is on 1.8, this should fail safely and continue afterwards.
4. Then, for checking if the hand is the off hand, just check if the boolean is true. This will only happen if it is on 1.8, in which case it will always be true, or if in 1.9-1.12 the event if for the mainhand.

The 'propper' way to do this would have been to use a bit of reflection and a wrapper, where the reflection checks if the getHand method exists and the wrapper controls whether to run 1.8-designed code or 1.9+ code. However, this requires knowledge in reflection and more lines to complete.

 

@Zombie_Striker

Code:

if(Bukkit.getVersion().contains("1.8");

Is also a nice way to get things to work sometimes. I mean I will leave this try-catch you suggested around it that for any special case that I cant predict right now but idk I like it with the version check as well