3 × Warnings: Foreach [closed] - php

Question

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
Closed 8 years ago.
Improve this question
I've a bit trouble with "foreach". The test page displays:
*Warning: Invalid argument supplied for foreach() in /data/web/virtuals/23481/virtual/www/subdom/vsohbrno/poi/junaio/junaio/test.php on line 60*
*Warning: array_multisort() [function.array-multisort]: Argument #1 is expected to be an array or a sort flag in /data/web/virtuals/23481/virtual/www/subdom/vsohbrno/poi/junaio/junaio/test.php on line 64*
*Warning: Invalid argument supplied for foreach() in /data/web/virtuals/23481/virtual/www/subdom/vsohbrno/poi/junaio/junaio/test.php on line 68*
However I make it for Junaio (AR application for smartphone) - and when I tried to run it here (in the app), I had no trouble with it - it's working. But if the warnings will be disappear also in www pages, it would be fine =o)
My source code:
<?php
require_once '../ARELLibrary/arel_xmlhelper.class.php';
if(!empty($_GET['l']))
$position = explode(",", $_GET['l']);
else
trigger_error("user position (l) missing. For testing, please provide a 'l' GET parameter with your request. e.g. pois/search/?l=23.34534,11.56734,0");
//create the xml start
ArelXMLHelper::start(NULL, "/arel/index.html");
//start by defining some positions of geo referenced POIs and give those names and thumbnails
$treasureLocations = array(
array("48.6045911000,14.7007322000,0", "Tradiční výroba marmelád a povidel ", "Jih Čech > Šumava > Šumava a Pošumaví. Obec: Pohorská Ves."),
array("48.6438239000,14.2208661000,0", "Restaurace Czech Specials (Restaurace Lanovka)", "Jih Čech > Šumava > Šumava a Pošumaví. Obec: Lipno nad Vltavou."),
array("48.6541914000,14.0354000000,0", "Plavení dřeva, vorařství – Schwarzenberský plavební kanál", "Jih Čech > Šumava > Šumava a Pošumaví. Obec: Přední Výtoň."),
);
//in the filter_value, the continent parameter will be send from the client, once the continent is filtered
$filter = $_GET['filter_value'];
//display the POIs as defined in the Constructor
$countpoi = 1;
foreach($treasureLocations as $i => $findPOI)
{
//Parameters for distance calculate. $Location = GPS coordinates of the POI, $Position = my GPS position.
$location = explode(",", $findPOI[0]);
//Calculate distance beween my position and POI
$deg2RadNumber = (float)(pi() / 180);
$earthRadius= 6371.009;
$latitudeDistance=((float)$position[0]-(float)$location[0])*$deg2RadNumber;
$longitudeDistance=((float)$position[1]-(float)$location[1])*$deg2RadNumber;
$a=pow(sin($latitudeDistance/2.0),2) + cos((float)$position[0]*$deg2RadNumber) * cos((float)$location[0]*$deg2RadNumber) * pow(sin($longitudeDistance/2.0),2);
$c=2.0*atan2(sqrt($a),sqrt(1.0- $a));
$distance=round($earthRadius*$c);
//Set distance for displaying objects (in kilometers)
if($distance < 10)
{
$title = $findPOI[1]; //Title of the POI
$poi[$countpoi]['attribution'] = $findPOI[2]; //Description of the POI
$poi[$countpoi]['distance'] = $distance; // Distance between POI and me
//create the POI
$poi[$countpoi]['poi'] = ArelXMLHelper::createLocationBasedPOI($i, $title, explode(",", $findPOI[0]), "http://vsohbrno.chudst.cz/poi/poi_obrazek.png", "http://vsohbrno.chudst.cz/poi/poi_obrazek.png", $poi[$countpoi]['attribution'], NULL);
$countpoi++;
}
}
//Sorting POI (the closest -> the furthest)
foreach ($poi as $val)
{
$sortarray[] = $val['distance'];
}
array_multisort($sortarray,$poi);
//Write 39 POI to XML file
foreach ($poi as $POInumber => $POIvalue)
{
if($POInumber < 39){
if(!empty($filter))
{
if(strtolower($filter) == strtolower($poi[$POInumber]['attribution']))
{
ArelXMLHelper::outputObject($poi[$POInumber]['poi']);
}
}
else
{ArelXMLHelper::outputObject($poi[$POInumber]['poi']);}
}
}
//end the output
ArelXMLHelper::end();
?>

Answer 1

If the distance is never smaller than 10 km, $poi will not be initialised, which is what the error means.
Initialise $poi to be an array and it should remove the warnings:
$poi = array();