help w/gallery function - prev next links

[Alexandra]

I'm working on a photo gallery which needs to allow the user to cycle through images like they are using the view photo feature in windows xp (as the client put it), so I need to setup some "previous" and "next" links.

I've set something up at the moment but it doesn't take note of the photo categories because it is based on the photos id, not category.

Does anybody know how I can go about setting this up so it sticks to the right category and still cycles through?

I don't have access to the code on this machine (my other doesn't have internet access atm as the isp is down), so I'm sorry I can't post that here. All I can say is the link takes the id of the current photo and either adds one or subtracts one - I know this the wrong way to do it, but I can't seem to figure out exactly what is required. I really hope this post is making sense.

Any help would be greatly appreciated!

[ChrisHasenpflug]

Well, I'm assuming the data is stored in a databse since you talked about IDs and such.

What you could do is run two querys like such...

SELECT photoID FROM photos WHERE (photoID < $displayed_photo_ID) AND (photoCat = $displayed_photo_category) ORDER BY photoID DSC LIMIT 1;

SELECT photoID FROM photos WHERE (photoID > $displayed_photo_ID) AND (photoCat = $displayed_photo_category) ORDER BY photoID DSC LIMIT 1;

[polvero]

here's what I did:

(reminder: this was pulled straight out of an old project I did...change the query's and table name's accordingly, but keep the same ORDER's etc...)

function prev_next( $pr,$nx )
{
    $nav = '<a href="'.$self.'?pg_cat='.$_GET['pg_cat'].'&amp;photo='.$pr.'">&laquo; Previous</a>';
    $nav .= ' | ';
    $nav .= '<a href="'.$self.'?pg_cat='.$_GET['pg_cat'].'&amp;photo='.$nx.'">Next &raquo;</a>';
    return $nav;
}


$photo_prev_q = tep_db_query("SELECT m_id
FROM multimedia 
WHERE m_cat_id='$pgcat' 
AND m_type = 'Photo Gallery' 
AND m_id < '$photoid' 
AND m_status = 1 
ORDER BY m_id DESC 
LIMIT 1");

$photo_next_q = tep_db_query("SELECT m_id
FROM multimedia 
WHERE m_cat_id='$pgcat' 
AND m_type = 'Photo Gallery' 
AND m_id > '$photoid' 
AND m_status = 1 
ORDER BY m_id ASC 
LIMIT 1 ");

    // Grab Previous and Next ID's 
    while ( $photo_prev_r = tep_db_fetch_array($photo_prev_q) )
    {
    $prev = $photo_prev_r['m_id'];
    }
    while ( $photo_next_r = tep_db_fetch_array($photo_next_q) )
    {
    $next = $photo_next_r['m_id'];
    }
    if ( ($prev == '') && ($next == '') ) // don't go anywhere
    {
    $prev = $_GET['photo'];
    $next = $_GET['photo'];
    }
    elseif ( $prev == '' ) // loop to the last
    {
    $photo_prev_alt_q = tep_db_query("SELECT m_id
    FROM multimedia 
    WHERE m_cat_id='$pgcat' 
    AND m_type = 'Photo Gallery' 
    AND m_status = 1 
    ORDER BY m_id DESC 
    LIMIT 1");
        while ( $photo_prev_alt_r = tep_db_fetch_array($photo_prev_alt_q) )
        {
        $prev = $photo_prev_alt_r['m_id'];
        }
    }
    elseif ( $next == '' ) // loop to the first
    {
    
    $photo_next_alt_q = tep_db_query("SELECT m_id
    FROM multimedia 
    WHERE m_cat_id='$pgcat' 
    AND m_type = 'Photo Gallery' 
    AND m_status = 1 
    ORDER BY m_id ASC 
    LIMIT 1");
    
        while ( $photo_next_alt_r = tep_db_fetch_array($photo_next_alt_q) )
        {
        $next = $photo_next_alt_r['m_id'];
        }
    }
    // run our nifty function
    $prev_next = prev_next($prev,$next); 

[Alexandra]

Thanks guys. Sorry I should have mentioned I was using a database, good one for picking that up!

I'll try out what you've suggested and let you know if I have any problems. Thanks again!

[polvero]

oh yea, don't forget to echo $prev_next
but honestly, I know there is probably some nifty PEAR library function that can spit this out nice and easy, but I wouldn't have a clue.
The above code takes into consideration the possibilities of having only 1 photo or more.
Also, it loops thru back to the beginning once you've reached the end...and visa-versa.