paging like stackoverflow's - php

Question

i'm a newbie in php especially on making pagination.
my question is, how to make paging like stackoverflow's pagination?
i mean paging like this :
1 ... 5 6 7 8 9 ... 25
(the first number and the last number is always appear, but in the middle only 5 numbers with the selected page absolutely in the middle)
in php i have tried making paging,
<?php
//Show page links
for($i=1; $i<=$pages; $i++)
{
echo '<li id="'.$i.'">'.$i.'</li>';
}
?>
but it will be shown all of pages like
1 2 3 4 5 6 7 8 9 10 etc
any body have simple logic example to solve this problem?
many thanks :)

Answer 1

This will generate the numbers as per above with current = 7, pages = 25. Replace the numbers with links to get an actual pagination index.
$current = 7;
$pages = 25;
$links = array();
if ($pages > 3) {
// this specifies the range of pages we want to show in the middle
$min = max($current - 2, 2);
$max = min($current + 2, $pages-1);
// we always show the first page
$links[] = "1";
// we're more than one space away from the beginning, so we need a separator
if ($min > 2) {
$links[] = "...";
}
// generate the middle numbers
for ($i=$min; $i<$max+1; $i++) {
$links[] = "$i";
}
// we're more than one space away from the end, so we need a separator
if ($max < $pages-1) {
$links[] = "...";
}
// we always show the last page
$links[] = "$pages";
} else {
// we must special-case three or less, because the above logic won't work
$links = array("1", "2", "3");
}
echo implode(" ", $links);
Output:
1 ... 5 6 7 8 9 ... 25

Answer 2

Below is a snippet from a general pagination class1 I wrote a few years ago. I have edited it to show the relevant parts only.
// cntAround is the number of pages to show before and after the current
function renderNavigation($cntAround = 1) {
$out = '';
$isGap = false; // A "gap" is the pages to skip
$current = // Current page
$cntPages = // Total number of pages
for ($i = 0; $i < $pages; $i++) { // Run through pages
$isGap = false;
// Are we at a gap?
if ($cntAround >= 0 && $i > 0 && $i < $cntPages - 1 && abs($i - $current) > $cntAround) { // If beyond "cntAround" and not first or last.
$isGap = true;
// Skip to next linked item (or last if we've already run past the current page)
$i = ($i < $current ? $current - $cntAround : $cntPages - 1) - 1;
}
$lnk = ($isGap ? '...' : ($i + 1)); // If gap, write ellipsis, else page number
if ($i != $current && !$isGap) { // Do not link gaps and current
$lnk = '' . $lnk . '';
}
$out .= "\t<li>" . $lnk . "</li>\n"; // Wrap in list items
}
return "<ul>\n" . $out . '</ul>'; // Wrap in list
}
Example 1
cntAround = 1, current = 5, cntPages = 9:
[1] ... [4] 5 [6] ... [9]
Example 2
cntAround = 3, current = 5, cntPages = 11:
[1] [2] [3] [4] 5 [6] [7] [8] ... [11]
1) Article is in Danish. Google Translate'd version is here.

Answer 3

Somewhat like this(pseudo-code):
pg = CurrentPageNo
low = 1
high = MAX_PAGES
if (pg-low <=5)
output 1 to pg-1 [with links]
else
output 1..3 [with links]
output "..."
output (pg-3) to (pg-1) [with links]
output pg
if (high - pg <=5)
output pg+1 to high [with links]
else
output (pg+1) to high-3 [with links]
output "..."
output (high-2) to high [with links]

Answer 4

You could use Zend_Paginator to do just that, and learn to use the Zend Framework while you're at it.

Answer 5

Below is php classes link from where you can download php class for pagination.
http://www.phpclasses.org/search.html?words=paging&x=0&y=0&go_search=1

Answer 6

If you (might potentially) have a large number of pages, consider using "logarithmic" page navigation, as described here (sample code included):
How to do page navigation for many, many pages? Logarithmic page navigation
(Note that it'll work just fine for small numbers of pages, too, of course!)