Undefined offset: 1 twitch channel grab - arrays

Question

I get this on my website:
Notice: Undefined offset: 1 in ...
Here is the full code, bolded is the part it refers to i think, basically this scripts should grab list of my channels from ther DB and then display info from the twitch:
<?php
defined('_JEXEC') or die('Direct access to this location is not allowed.');
$userList = $params->get('userlist');
$usersArray = explode(',', $userList);
$userGrab = "http://api.justin.tv/api/stream/list.json?channel=";
$checkedOnline = array ();
foreach($usersArray as $i =>$value){
$userGrab .= ",";
$userGrab .= $value;
}
unset($value);
$json_file = file_get_contents($userGrab, 0, null, null);
$json_array = json_decode($json_file, true);
//used to be $viewer = $json_array[$i]['stream_count'];
**foreach($usersArray as $i =>$value){
$title = $json_array[$i]['channel']['channel_url'];
$array = explode('/', $title);
$member = end($array);
$name = $json_array[$i]['name'];
$game = $json_array[$i]['meta_game'];
$viewer = $json_array[$i]['channel_count'];
$topic = $json_array[$i]['title'];
onlinecheck($member, $viewer, $topic, $game);
$checkedOnline[] = signin($member);
}**
unset($value);
unset($i);
function onlinecheck($online, $viewers, $topic, $game)
{
if ($game == "Counter-Strike: Global Offensive")
{
$igra = "csgo12.jpg";
}
else{
$igra = "online.png";
}
if ($online != null)
{
echo ' <img src="./modules/mod_twitchlist/tmpl/'.$igra.'">';
echo ' <strong>'.$online.'</strong>';
echo ' (' .$viewers.') - ';
echo '<strong>'.$topic.'</strong> </br>';
}
}
function signin($person){
if($person != null){
return $person;
}
else{
return null;
}
}
?>
<!-- <hr> -->
<?php
foreach ($usersArray as $i => $value1) {
foreach($checkedOnline as $ii => $value2){
if($value1 == $value2){
unset($usersArray[$i]);
}
}
}
$broj1 = count($usersArray); //neaktivni korisnici
$broj2 = count($checkedOnline); //ukupno streamova
if ($broj1 == $broj2){
echo '<strong><center>Nijedan stream nije aktivan trenutno!</center></strong>';
}
?>
Any hints?