Show next and previous keys of an array with cycling - php

Question

I'm sure you're gonna like it ;).
I need a function for building navigation for browsing pages in a book (where some pages could have been reaped apart and it should cycle back and forth); it should output links( as numbers) to the "next" and "previous" pages of the given page.
Function that will receive an array and a key on input should spit out the value of the given key of the array as well as a value of "next" and "previous" values. However if the given key is the first key in the array it should output last key of an array as "previous". Likewise, if it receives the last key, it should output the first key as "next".
Here's what I have so far:
$pages = array(5, 1, 6, 8);
sort($pages);
$selected = 1; // that's second key (value:5, next:6, previous:1)
// $selected = 3; // that's forth and a last key (value:8, should return next:1, previous:6)
$selected = key($pages)+$selected;
while ($pointer = current($pages)) {
if ($selected == key($pages) ) {
echo $pointer." - current <br>";
}
elseif($selected+1 == key($pages) ){
echo $pointer." - next <br>";
}
elseif($selected-1 == key($pages) ){
echo $pointer." - previous <br>";
}
else
echo $pointer."<br>";
next($pages);
}
THis should actually work (but without 'cycle awarness') - you can check quickly in http://writecodeonline.com/php/- if the description confuses you, output of this code is quite self explanatory...
I believe it's quite easy, but I'm out of ideas and it's 3 o'clock in the morning. Of course I need most simple solution, so ther could be some easier way, than the one I've chosen.

Answer 1

I think this is solution of your problem. Tell me if it's doing what you want (Some checking if you're going out of array bounds will be good :) but let's stick to simplicity...):
/* This is from your code */
$pages = array(5, 1, 6, 8);
sort($pages);
$selected = 1; // that's second key (value:5, next:6, previous:1)
$selected = 3; // that's forth and a last key (value:8, should return next:1, previous:6)
/* ... */
$pages_count = count($pages);
$pages_ordered = array();
$pages_ordered["current"] = $pages[$selected];
foreach($pages as $order_number => $page)
{
if($selected == 0) {
$pages_ordered["previous"] = $pages[$pages_count - 1];
$pages_ordered["next"] = $pages[$selected + 1];
} elseif($selected == ($pages_count - 1)) {
$pages_ordered["next"] = $pages[0];
$pages_ordered["previous"] = $pages[$selected - 1];
} else {
$pages_ordered["next"] = $pages[$selected + 1];
$pages_ordered["previous"] = $pages[$selected - 1];
}
}
print_r($pages_ordered);

Answer 2

It really is pretty simple to be honest.
$pages = array(5, 1, 6, 8);
sort($pages);
//how many pages do we have
$total = count($pages);
//replace with $_GET['page']; when ready
$requested_page = rand(0, ($total -1)); //$_GET['page'];
//the selected page
$selected = $pages[$requested_page];
//if this isn't the first page
if($selected != $pages[0]):
//get the previous page
$prev = $requested_page-1;
//standard issue
echo '<a style="margin:0 15px;" href="myscript.php?page=', $pages[$prev] ,'"> Previous </a>';
endif;
//iterate each page
foreach($pages as $page):
//a ternary operator to assign a class if this is the current page we're on or not
$cls = ($page == $selected ) ? 'active' : false; //for your current page class
//you don't need the style
echo '<a class="', $cls ,'" href="myfile.php?page=', $page ,'">', $page ,'</a>';
endforeach;
//if this is not the last page
if(selected != $pages[$total]):
//our next page
$next = $requested_page+1;
//standard issue
echo ' Next ';
endif;

Answer 3

Try this function
function get_nav($arr,$current){
while($nav = current($arr)){
if(key($arr)==$current){
$prev =prev($arr);
empty($prev)?reset($arr):'';
next($arr);
$r = current($arr);
$next = next($arr);
prev($arr);
return array('prev'=>$prev,'current'=>$r,'next'=>$next);
}
next($arr);
}
return FALSE;
}
$pages = array(5, 1, 6, 8);
sort($pages);
$selected = 0;
$res = get_nav($pages,$selected);