save hotbar

i have this code:

PHP:

//save hotbar
$hotbar = [];
$inv = $player->getInventory();
for($i = 0; $i < 7; $i++){
     $hotbar[$i] = $inv->getHotbarSlotIndex($i);
}

//load hotbar
for($i = 0; $i < 7; $i++){
      $inv->setHotbarSlotIndex($hotbar[$i], $i);
}
$inv->sendContents($player);


but this doesnt work :/ what is wrong?

Maybe swap $hotbar[$i] and $i in the setting function?

Are you in creative?
Creative hotbar is different from a survival one.

In creative, $inv->hotbar[] is always {0,1,2, ...,8} . Data is in $slots[].
Use getItem() and setItem().

No survival