Gallery Help

[gfX]

Hey guys,
I have a gallery for a website: http://www.vivagaete.com/gallery.php
If you click on the thumbnail it will bring up viewgallery.php - which has the larger image on it.

What I want, is for viewgallery.php to have the options for "PREVIOUS and NEXT" images.  So they don't have to click "Click here to Go Back" every time, they can browse by clicking the NEXT link or PREVIOUS.

How would I go about doing this to pull the next image ID from the database?
Here is the code for viewgallery.php:

[code]
<style type="text/css">
.greentext {
color: #2a8f3d;
margin: 4px;
font-family: Tahoma;
font-size: 19px;
}
.blacktext {
color: #000000;
margin: 4px;
font-family: Tahoma;
font-size: 11px;
}
</style>

<?
include 'db.php';
$getid = $_GET['id'];
$sql = "SELECT * FROM gallery WHERE id = $getid";
$result = mysql_query($sql);
while ($row = mysql_fetch_array($result)) {
$picture = $row['picture'];
$heading = $row['heading'];
$description = $row['description'];
}

$sql2 = "SELECT id FROM gallery WHERE id > $id LIMIT 1";
$result2 = mysql_query($sql2);
while ($row = mysql_fetch_array($result)) {
$id = $row['id'];
}

if ($getid == "$id") {

echo "<center>
<FORM>
$id
<INPUT type='button' value='Click here to go back' onClick='history.back()'>
</FORM>
<div class=\"greentext\"><b>$heading</b></div>
<div class=\"blacktext\">$description</div><br />
<img src=\"images/$picture\" style=\"border: 2px solid #d4cccc;\"><br /><br />

<FORM>
<INPUT type='button' value='Click here to go back' onClick='history.back()'>
</FORM></center>";

} else {

echo "No image verfied";

}

?>
[/code]

Thanks a lot!!

[mansuang]

The easiest way:
[code=php:0]
<a href="<?=$_SERVER['PHP_SELF']; ?>?id=<?=((int)$_GET['id']-1); ?>">Previous</a>
<a href="<?=$_SERVER['PHP_SELF']; ?>?id=<?=((int)$_GET['id']+1); ?>">Next</a>
[/code]

[Philip]

However with the post above, you will want to have an if statement checking to see if there is that photo in the DB.

Ex: click on it more than once and you could get  id=-1

[gfX]

Thanks for the replies!
That did work, but like KingPhilip said, I need it to check if it is in the database to get the right ID's.

How would I make that if statement?
Thanks a lot for the help.

[Philip]

This should work (it has been a while since I've done some coding, so let me know if I made a mistake somewhere)

[code]
<style type="text/css">
.greentext {
color: #2a8f3d;
margin: 4px;
font-family: Tahoma;
font-size: 19px;
}
.blacktext {
color: #000000;
margin: 4px;
font-family: Tahoma;
font-size: 11px;
}
</style>

<?php
include 'db.php';
$getid = $_GET['id'];
$sql = "SELECT * FROM gallery WHERE id = $getid";
$result = mysql_query($sql);
$total_rows = mysql_num_rows($sql); // find out how many rows are in that table, see what the max number is
while ($row = mysql_fetch_array($result)) {
$picture = $row['picture'];
$heading = $row['heading'];
$description = $row['description'];
}

$sql2 = "SELECT id FROM gallery WHERE id > $id LIMIT 1";
$result2 = mysql_query($sql2);
while ($row = mysql_fetch_array($result)) {
$id = $row['id'];
}

if ($getid == "$id") {
echo "<div align='center'>
  <div class=\"greentext\"><b>$heading</b></div>
  <div class=\"blacktext\">$description</div><br />
  <img src=\"images/$picture\" style=\"border: 2px solid #d4cccc;\"><br /><br />";
  if(($getid-1) <= 0) { // if id in link is less than or equal to 0
  echo "Previous Image"; // show just text
  } else {
  $id_prev = $getid-1; //otherwise, set variable
  echo "<a href='/viewgallery.php?id=".$id_prev."'>Previous Image</a>"; // and show a link to previous image
  }
  echo " - "; // spacer between links
  if(($getid+1) > $total_rows) { //if the id in link is more than total rows
  echo "Next Image"; //show just normal text.. no link
  } else {
  $id_next = $getid+1; // otherwise, set variable
  echo "<a href='/viewgallery.php?id=".$id_next."'>Next Image</a>"; //and provide a link to next image
  }
  echo "</div>"; // end center
} else {
  echo "No image verfied";
}
?>[/code]

[i]edited to make it easier to read the code - ACK I forgot a semicolon.. sorry![/i]

[gfX]

Hey there,
Thakns for taking the time to supply that code!

I get: Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /hsphere/local/home2/andres30/vivagaete.com/viewgallery.php on line 21

Line 21: $total_rows = mysql_num_rows($sql); // find out how many rows are in that table, see what the max number is

http://www.vivagaete.com/viewgallery.php?id=5

[Philip]

Whoops, change those lines (19-21) to this:

[code]
<?php
$sql = "SELECT * FROM gallery WHERE id = $getid";
$result = mysql_query($sql);
$total_rows = mysql_num_rows($result); // find out how many rows are in that table, see what the max number is
?>[/code]

[gfX]

Great man, fixed that one.  Now the only problem is that there is no next link.  It just shows the text.
Any reason for that?

[Philip]

Try:

[code]
<style type="text/css">
.greentext {
color: #2a8f3d;
margin: 4px;
font-family: Tahoma;
font-size: 19px;
}
.blacktext {
color: #000000;
margin: 4px;
font-family: Tahoma;
font-size: 11px;
}
</style>

<?php
include 'db.php';
$getid = $_GET['id'];
$sql = "SELECT * FROM gallery WHERE id = $getid";
$result = mysql_query($sql);
$total_rows = mysql_num_rows(mysql_query("SELECT * FROM gallery")); // find out how many rows are in that table, see what the max number is
while ($row = mysql_fetch_array($result)) {
$picture = $row['picture'];
$heading = $row['heading'];
$description = $row['description'];
}

$sql2 = "SELECT id FROM gallery WHERE id > $id LIMIT 1";
$result2 = mysql_query($sql2);
while ($row = mysql_fetch_array($result)) {
$id = $row['id'];
}

if ($getid == $id) {
echo "<div align='center'>
  <div class=\"greentext\"><b>$heading</b></div>
  <div class=\"blacktext\">$description</div><br />
  <img src=\"images/$picture\" style=\"border: 2px solid #d4cccc;\"><br /><br />";
  if(($getid-1) <= 0) { // if id in link is less than or equal to 0
  echo "Previous Image"; // show just text
  } else {
  $id_prev = $getid-1; //otherwise, set variable
  echo "<a href='/viewgallery.php?id=".$id_prev."'>Previous Image</a>"; // and show a link to previous image
  }
  echo " - "; // spacer between links
  if(($getid+1) == $total_rows) { //if the id in link is more than total rows
  echo "Next Image"; //show just normal text.. no link
  } else {
  $id_next = $getid+1; // otherwise, set variable
  echo "<a href='/viewgallery.php?id=".$id_next."'>Next Image</a>"; //and provide a link to next image
  }
  echo "</div>"; // end center
} else {
  echo "No image verfied";
}
?>[/code]

Also, I just noticed you're not always having a numerical order - like you start at 5, there isn't a 15, etc.

Which, my code will work, but you're going to be cutting off a few images at the end and it will show the images that aren't there -- I recommend just making your table be numerical order.

Or, if somebody else would like to post some code showing how to do it another way ;)

[gfX]

Ah Thanks, that worked.
Yeah that's from images being deleted from the database :(
I wish that could be fixed, but other than that I really appreciate it!

Thakns so much

[Philip]

Not a problem :D