Check if player hits some mob

Hello friends i tried to use this code to check if player hits some mob, but when i hit mob nothing happens.
What's wrong with my code???

PHP:

public function onDamage(EntityDamageEvent $ev){
if($ev instanceof EntityDamageByEntityEvent) {
$entt = $ev->getEntity();
$damger = $ev->getDamager();
if($entt instanceof Creeper) {
$ev->setCancelled();
$damager->sendMessage("§l§eCREEPER");
}
}
}


---------------------------
Answer please if you know, i'll be very happy! ^-^

And I know about slapper plugin, but that code didn't help me(

what is los

PHP:

$los->setCancelled();
// FIX
$ev->setCancelled();


PHP:

public function onDamage(EntityDamageEvent $ev){
if($ev instanceof EntityDamageByEntityEvent) {
$entt = $ev->getEntity();
$damger = $ev->getDamager();
if($entt instanceof Creeper) {
$ev->setCancelled();
$damager->sendMessage("§l§eCREEPER");
}
}
}


but it don't work too...

Thx for your reply))

oh it still not working

WTF it can... Don't mislead others. First, did you register events??

yeah

PHP:

public function onEnable(){
        $this->getLogger()->info("Плагин запуск........");
        $this->getServer()->getPluginManager()->registerEvents($this,$this);
    }


but it don't works...

idk what's the problem(((

Ah are you using the newest PM build?

i use genysis core(modified pocketmine)

thanks every1 i solved it , the problem was in import lol

PHP:

$damger = $ev->getDamager();
$damager->sendMessage("§l§eCREEPER");


If this was copied and pasted here, be careful on spellings.