simple image slideshow not working in php

[silverglade]

Hi, I'm trying to make a simple slideshow with forward and back buttons that change the image inside a div in php. When I press the "further" button, it jumps from index[0] to index[1] and never shows the first image. Then when I click more it doesn't go forward. When I click back, it goes back to a black screen div. Any help getting this to work is GREATLY appreciated because I've been trying for 2 days with tutorials and can't get it. Thanks. Derek

 

Here are the php parts that are relevant, my page was too large and confusing to include.

 

first, the $background array where I store my images.

 

$background = array
(
"<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
"<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>"
);

 

then the code to move the images forward and backwards if the buttons are pressed.

 

if(!empty($_POST['further']))
{
  $currentBackground=next($background);
}
elseif(!empty($_POST['back']))
{
$currentBackground=prev($background); 
} 

 

and now to echo out the images inside the div.

 

<div id="background"><?php echo $currentBackground;?></div>

[trq]

Like all things php, the $background array doesn't persist across requests. So calling prev() or next() isn't going to work, because upon each request the internal pointer within the $background array will be reset.

 

You would at minimum need to store your images within the $_SESSION array which IS persistent. Really though, this would all be better done using Javascript instead of php.

[silverglade]

awesome!! thanks very much. I waited like 2 or 3 days for that. LOL. I don't know javascript, and I looked up "javascript image galleries" and none of them were good for the job, I needed a simple , forward and back image gallery . I altered my code according to what you said but I can't get it to work. Is this right? please.

 

I was unsure of the syntax, so i tried both $_SESSION['background'] and $_SESSION[$background] because I wasn't sure. Neither worked. I got a black screen at the starting point, and the next button worked. But when I start and click back I get a black screen. I have session_start(); at the top of my page.

 

here is the new array

 

$_SESSION['background'] = array
(
"<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
"<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>"
);

 

and here is the POST check.

 

if(!empty($_POST['further']))
{	
     $currentBackground=next($_SESSION['background']);
}
elseif(!empty($_POST['back']))
{
$currentBackground=prev($_SESSION['background']); 
} 

 

and here is the echoing out of the new image.

 

<div id="background"><?php echo $currentBackground;?></div>

 

Please any more help GREATLY appreciated! I'm almost there pleeease.  :D

[trq]

You need to call session_start before you can make use of the $_SESSION array.

 

You should also be using isset instead of empty and checking for values, not a lack of.

 

if (isset($_POST['further']))
{   
     $currentBackground=next($_SESSION['background']);
}

if(isset($_POST['back']))
{
   $currentBackground=prev($_SESSION['background']);
}

[silverglade]

Great Thorpe thanks again , I changed it, and I had session_start(); at the top of my page before anything else. then next in the page comes this.

 

$_SESSION['background'] = array
(
"<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
"<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>"
);

 

then comes this

 

if(isset($_POST['further']))
{


     $currentBackground=next($_SESSION['background']);
}
elseif(isset($_POST['back']))
{
$currentBackground=prev($_SESSION['background']); 
} 

 

and then the echoing out of the images.

 

<div id="background"><?php echo $currentBackground;?></div>

 

and the first frame wont show up it's black. Because I have a black background.

 

If you know of anything else please let me know. Thanks. I might just have to look for javascript solutions but then again if I can't even do this....lol.

[trq]

This will keep resetting the array as well.

 

$_SESSION['background'] = array
(
"<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
"<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>"
);

 

Needs to be....

 

if (!isset($_SESSION['background'])) {
  $_SESSION['background'] = array
  (
    "<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
    "<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>"
  );
}

[silverglade]

I tried that and it still only goes to the second frame and won't show the first, I created a new file just for this little application to test it and it doesn't work. Sorry about that. Thanks for helping me.

 

Here is the code I used though.

 

<?php
session_start();



if (!isset($_SESSION['background'])) {
  $_SESSION['background'] = array
  (
    "<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
    "<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>",
"<img src='sundragon_environments/ocean/ocean1_FRAME3.jpg'/>",
"<img src='sundragon_environments/ocean/ocean1_FRAME4.jpg'/>",
"<img src='sundragon_environments/ocean/ocean1_FRAME5.jpg'/>"
  );
}

if(isset($_POST['further']))
{
     $currentBackground=next($_SESSION['background']);
}
elseif(isset($_POST['back']))
{
$currentBackground=prev($_SESSION['background']); 
} 
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

<?php echo $currentBackground;?>

<form action='NAVIGATION.php' method='post'>
<input type="submit" value="go further" name="further" /> <input type="submit"value="Go back" name="back"/></form>
</body>
</html>

[dolrichfortich]

How about this.

 

<?php
session_start();


if (!isset($_SESSION['background'])) {
  $_SESSION['background'] = array
  (
    "<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
    "<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME3.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME4.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME5.jpg'/>"
  );
}

if(isset($_POST['further']))
{
     $currentBackground=next($_SESSION['background']);
}
elseif(isset($_POST['back']))
{
   $currentBackground=prev($_SESSION['background']); 
} 
else
{
  $currentBackground=$_SESSION['background'][0]; 
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

<?php echo $currentBackground;?>

<form action='NAVIGATION.php' method='post'>
<input type="submit" value="go further" name="further" /> <input type="submit"value="Go back" name="back"/></form>
</body>
</html>

[silverglade]

hey Dolrich! I still have my Bossgrader and Toptenbox.net haha! Thanks! That code doesn't work either though , it behaves the same way as I described above. Sorry about that, someone in another forum said I might be trying to do something php can't do. I don't know. Here is the code I used though.

 

Thanks. Derek.

 

<?php
session_start();


if (!isset($_SESSION['background'])) {
  $_SESSION['background'] = array
  (
    "<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
    "<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME3.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME4.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME5.jpg'/>"
  );
}

if(isset($_POST['further']))
{
     $currentBackground=next($_SESSION['background']);
}
elseif(isset($_POST['back']))
{
   $currentBackground=prev($_SESSION['background']); 
} 
else
{
  $currentBackground=$_SESSION['background'][0]; 
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

<?php echo $currentBackground;?>

<form action='NAVIGATION.php' method='post'>
<input type="submit" value="go further" name="further" /> <input type="submit"value="Go back" name="back"/></form>
</body>
</html>

[dolrichfortich]

Oh, its you. How was your photography site? 

 

By the way, try this one. This should work. 

<?php
session_start();


if (!isset($_SESSION['background'])) {
  $_SESSION['background'] = array
  (
    "<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
    "<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME3.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME4.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME5.jpg'/>"
  );
}
if(!isset($_SESSION['current_background']))
{
$_SESSION['current_background'] = 0;
}

if(isset($_POST['further']))
{
$_SESSION['current_background'] = isset($_SESSION['background'][$_SESSION['current_background'] + 1]) ? ($_SESSION['current_background'] + 1) : 0;
}
elseif(isset($_POST['back']))
{
   $_SESSION['current_background'] = isset($_SESSION['background'][$_SESSION['current_background'] - 1]) ? ($_SESSION['current_background'] - 1) : count($_SESSION['background']);
} 

$currentBackground=$_SESSION['background'][$_SESSION['current_background']];
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

<?php echo $currentBackground;?>

<form action='NAVIGATION.php' method='post'>
<input type="submit" value="go further" name="further" /> <input type="submit"value="Go back" name="back"/></form>
</body>
</html>

[silverglade]

Yeah its me Dolrich. You did an AWESOME job coding my sites. Even though neither of them made money. HAHA. Now I'm trying to learn php to make a game. I like php when I'm trying to make games. Other than that I dislike business apps and such. But we'll see. Also, thank you so much for taking the time to code that! I get the following errors though, upon loading it doesn't start at image 1 after I use it, it loops past image 5, and it gives me this error too. If you want to stop you can LOL. I haven't been able to do this for hours and hours. So any more ideas you have or time is GREATLY appreciated. Thanks .Derek.Here is the error:

 

Notice: Undefined offset: 5 in C:\wamp\www\SUN_DRAGON_GAME\NAVIGATION.php on line 35

 

and here is the code as I have it now

 

<?php
session_start();


if (!isset($_SESSION['background'])) {
  $_SESSION['background'] = array
  (
    "<img src='sundragon_environments/ocean/ocean1_FRAME.jpg'/>",
    "<img src='sundragon_environments/ocean/ocean1_FRAME2.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME3.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME4.jpg'/>",
   "<img src='sundragon_environments/ocean/ocean1_FRAME5.jpg'/>"
  );
}
if(!isset($_SESSION['current_background']))
{



$_SESSION['current_background'] = 0;
}

if(isset($_POST['further']))
{



$_SESSION['current_background'] = isset($_SESSION['background'][$_SESSION['current_background'] + 1]) ? ($_SESSION['current_background'] + 1) : 0;
}
elseif(isset($_POST['back']))
{
   $_SESSION['current_background'] = isset($_SESSION['background'][$_SESSION['current_background'] - 1]) ? ($_SESSION['current_background'] - 1) : count($_SESSION['background']);
} 

$currentBackground=$_SESSION['background'][$_SESSION['current_background']];
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

<?php echo $currentBackground;?>

<form action='NAVIGATION.php' method='post'>
<input type="submit" value="go further" name="further" /> <input type="submit"value="Go back" name="back"/></form>
</body>
</html>

[dolrichfortich]

Hahaha. By the way, heres the fix.

 

Change this code

$_SESSION['current_background'] = isset($_SESSION['background'][$_SESSION['current_background'] - 1]) ? ($_SESSION['current_background'] - 1) : count($_SESSION['background']);

 

To this

$_SESSION['current_background'] = isset($_SESSION['background'][$_SESSION['current_background'] - 1]) ? ($_SESSION['current_background'] - 1) : count($_SESSION['background'])-1;

 

To force it to start with the first image. Use this code

if(( ! isset($_SESSION['current_background'])) OR (! $_POST))
{
    $_SESSION['current_background'] = 0;
}

 

[silverglade]

Haha! It got rid of  the error message! AND it starts on the first frame image! LOL Dolrich you're a LOGIC MONSTER!! hehehe. It does loop past the 5th image though, but I won't ask you for more that is a lot. Now I have to go back and understand it all so I learn. I don't use code anymore unless I understand how it works. So I'm guessing it will take me like an hour to figure out that puzzle. I have to start thinking things out but some of the things you did are pretty beyond me, so I'll have to study. Thanks so much! Derek  :D

If I come up with any more grandiose money making schemes I'll look you up again. Thanks.

[dolrichfortich]

Hahaha. Glad I could help.

Just send me a message if you need help with your money making ideas in mind. 

 

By the way, heres an explanation of the single line code I used.

http://www.tuxradar.com/practicalphp/3/12/4

[silverglade]

cool thanks! ya it's "if this, then that, otherwise: the other thing. hehe. thank you. Derek