I need help with php if(…) statement

[joe_ma]

Hello

I am playing around with the bootstrap profile. I'd like to use the carousel to display images, but only, if there are any. So I tried to write a function that I can use in the template. The function looks like this:

function slider() {

	$albumimages = wire("page")->slider;
		
		$out =" ";
		
	if ($albumimages) {

    	$out .= "<div id='myCarousel' class='carousel slide' data-ride='carousel'><div class='carousel-inner'>";

			$i=0;     

    		foreach ($albumimages as $albumimage) {

    			if ($i == 0)
				{
            		$out .= "<div class='item active'>";

				}
				else {

		    		$out .= "<div class='item'>";
				}
				$i++;
	

            	$out .= "<img class='img-responsive' src='{$albumimage->size(1170, 550)->url}'>";

            	$out .= "<div class='container'></div></div>";
    		}
		
		$out .="</div><a class='left carousel-control' href='#myCarousel' data-slide='prev'><span class='glyphicon glyphicon-chevron-left'></span></a><a class='right carousel-control' href='#myCarousel' data-slide='next'><span class='glyphicon glyphicon-chevron-right'></span></a>
    </div>";

    	echo $out;
	}

	else {
 		$out =" ";
		 echo $out;	
	}

}

It works ok on pages that do have images. But on pages without images, it still is writing all the html.

I don't find out, where I went wrong with the if-statement. Help is therefore very much needed and appreciated.

Thanks

[3fingers]

Hi joe_ma,

not sure if this is going to work (not tested) but you can try this:

function slider() {

	$albumimages = wire("page")->slider;
		
		$out =" ";
		
	if (count($albumimages)) { // COUNT IF SLIDER FIELD IS POPULATED WITH IMAGES, NOT ONLY IF IT EXISTS

    	// REST OF THE CODE...

Basically now you are checking if your slider exists in your template, and it always does. If you add count() function you can check if it is populated with images.

Try it, let me know if it solves your problem

Cya!

[joe_ma]

Yessssssssssss!!

Thank you very much 3fingers. You made my day.

[3fingers]

You're welcome

[Pete]

It doesn't particularly need to be in a function, also I'm not sure why you're using wire() since in a template you can just use $page directly - anyway, you can get rid of the } else { if you start it a bit like this instead:

$out = ''; // Starting with this means you don't need } else { as it's defined and empty to begin with
if ($page->slider->count() > 0) { // There's no overhead in just doing this count directly instead of assigning it to another variable
    // ... more of your code here
    foreach ($page->slider as $albumimage) { // Again, you can just user $page->slider directly here
        // ... the rest of your code here

[joe_ma]

Thanks Pete

I have tried your solution. But that throws an error:

Error:     Call to a member function count() on a non-object

Or can't I use your solution in a function, but only directly in the template?

[kongondo]

In a function you want to use wire('page') or $wire->page....same is true for other PW variables...Something about PHP scope whose name I always forget...

If in a class (module)....there's also $this....

Edited March 7, 2014 by kongondo

[joe_ma]

Thanks kongondo for the clarification.

[Pete]

Yeah, in my version you don't need it to be in a function unless you are using this code on many different templates? If it's just in one template then the function isn't needed.

[joe_ma]

Obviously I still don't seem to get it right. I have just encountered another one I can't solve.

I have a template, that I use for different kinds of news. The newsposts are in different folders. For news in one of the folders I want to display sort of a «Back»-button, news in the other folder don't need that button. So I have tried this:

if ($page->parentID=1016) {
      echo '<p class="retour"><a class="btn btn-default" role="button" href="'.$pages->get("title=Anlässe")->url .'">Zurück zur Übersicht</a></p></div>;
}

But that has no effect at all. The «Back»-Button is displayed in all the newsposts of both folders, not only in the folder with the ID=1016.

I have also tried

if ($page->parentID="1016") {

and

if ($page->parent->title="Notti") {

with the same results.

Thank you for help.

[onjegolders]

if ($page->parent->id == "1016") {

}

EDIT: You may not need the "" there.

also

if ($page->parent->title == "Notti") {

  echo...

}

[joe_ma]

Small cause, great impact …

Thank you onjegolders, that solved it.

[Pete]

Just to explain what went wrong - firstly, parentID doesn't exist. You would use $page->parent->id as in the corrected example above, so you are saying "this page's parent's ID" (or "the ID belonging to the parent of this page" if you read it from right to left, which sort of makes more sense if you read it to yourself that way).

The other issue was = versus == which I'll cover below:

// A single equals sign means you are assigning a value of 1016 to $page->parent->id in this case:
$page->parent->id = 1016
// So literally, $page->parent->id now has a value of 1016 because you told it to. Similarly, $something = 'a value'; means that if you echo $something it will output "a value".

// A double equals sign means "equals", so
if ($page->parent->id == 1016) {
// means "if $page->parent->id is equal to 1016"

There are lots more ternary operators besides == which you can read up on here, as you'll probably use some of them a lot: http://uk3.php.net/ternary

[joe_ma]

Thank you Pete for these explanations. I really appreciate help in php matters.

parentID doesn't exist

Ah, but in the cheatsheet it does. And in fact

if ($page->parentID == 1016)

is working like expected.

[Pete]

You're abosolutely right. It's a tad more efficient than $page->parent->id as well as ProcessWire isn't having to load the parent page into memory to get the ID.

If you click on $page->parentID on the cheatsheet there's also an alias of parentID called parent_id which does the same thing.