Set an array from class and get him outside a class - php

Question

I would create an array with ID posts from inside a function, and get him outside the class.
My code:
<?php
class cat_widget extends WP_Widget {
private $newHomePost = array();
function widget($args, $instance){
//...
foreach($img_ids as $img_id) {
if (is_numeric($img_id)) {
$this->setNewHomePost($newsCounter,$post->ID);
$newsCounter++;
//...
}
}
}
function setNewHomePost($num, $value){
$newHomePost[$num] = $value;
}
function getNewHomePost(){
return "ID: ".$this->newHomePost[0];
}
}
$testA = new cat_widget();
echo $testA->getNewHomePost();
?>
I receive on screen this resuld:
ID:
(without the id)
But if I insert inside setNewHomePost() an echo for the array, I'll obtain correctly the array but inside and not outside class.
function setNewHomePost($num, $value){
$newHomePost[$num] = $valore;
echo $newHomePost[0];
}
So seem that the array works fine inside the "function widget", but doesn't works outside it.
Can someone help me, please?

Answer 1

function setNewHomePost($num, $value){
$newHomePost[$num] = $value;
}
This creates a local variable named $newHomePost, setting a value at an index and returning. Once it returns, the local variable disappears. From the linked manual page:
Any variable used inside a function is by default limited to the local function scope.
You want to set the class member property newHomePost instead:
function setNewHomePost($num, $value) {
$this->newHomePost[$num] = $value;
}
Update
This is how you currently have the get method defined:
function getNewHomePost() {
return "ID: " . $this->newHomePost[0];
}
I suspect you're still fiddling with this and trying to get it to work. If you really want to just only ever return the 0'th index, try something like this instead:
function getNewHomePost() {
return isset($this->newHomePost[0]) ? $this->newHomePost[0] : null;
}
When building a class remember that you cannot make any assumptions about what order your public methods can be called from another object or calling code (even if the calling code itself exists inside of the class. The methods are public, meaning anything can call them). The code above assumes nothing in that you do not have to call addNewHomePost prior to getNewHomePost. I imagine if you look in your logs you may see a few Notice: Undefined index.. type errors.
Also be sure to check on the calling side:
$myClass = new cat_widget;
$myClass->setNewHomePost(0, 'my new home post!');
$homePost = $myClass->getNewHomePost();
echo $homePost ? $homePost : 'None';
I think a better getter method would probably look like this:
function getNewHomePost($i) {
return isset($this->newHomePost[$i]) ? $this->newHomePost[$i] : null;
}