arrow navigation

[nade93]

Hi

 

I am trying to work a simple arrow (left right) navigation and the arrows only appear if there is a slide to navigate to

 

For example. THe page is set up to detect content based on the slides number. This is taken from the database. I am using the following code at present

 

<a href="mod_one.php?slideno=<? echo $row['current_slide'] -1 ?>"><img src="../img/layout/previous-arrow.png" alt="previous slide" border="0" /></a>
<a href="mod_one.php?slideno=<? echo $row['current_slide'] +1 ?>"><img src="../img/layout/next-arrow.png" alt="next slide" border="0" /></a><

 

I need something that only shows the arrow if there is a next slide in the database or a previous one.

 

Please can anyone help?

 

 

[ignace]

You need a Paginator like:

 

class Paginator implements Iterator {
    private $key = 0;
    private $sizeOf = 0;
    private $itemsPerPage;
    private $data = array();
    private $activePage = 1;

    public function __construct($array, $itemsPerPage) {
        $this->data = $array;
        $this->sizeOf = sizeof($array);
        $this->itemsPerPage = abs((int)$itemsPerPage);
    }

    public function getItemsForPage($pageNumber) {
        $pageNumber = $pageNumber > 0 ? $pageNumber : 1;
        $pageNumber = $pageNumber < $this->getNumberOfPages() ? $pageNumber : $this->getNumberOfPages();

        $this->activePage = $pageNumber;
        $this->key = $this->calculateOffset($pageNumber);
        return $this;
    }

    public function getActivePage() {
        return $this->activePage;
    }

    public function getNumberOfPages() {
        return ceil($this->sizeOf / $this->itemsPerPage);
    }

    public function valid() {
        return $this->key < $this->calculateOffset($this->getActivePage() + 1) &&
               $this->key < $this->sizeOf;
    }

    public function key() {
        return $this->key;
    }

    public function next() {
        $this->key++;
    }

    public function rewind() {
        //$this->key = 0;
    }

    public function current() {
        return new ArrayObject($this->data[$this->key], ArrayObject::ARRAY_AS_PROPS);
    }

    private function calculateOffset($pageNumber) {
        return ($pageNumber - 1) * $this->itemsPerPage;
    }
    
    public function hasNextPage() {
        return $this->getActivePage() < $this->getNumberOfPages();
    }
    
    public function hasPreviousPage() {
        return $this->getActivePage() > 1;
    }
}

 

Use it like:

 

$rows = $db->execute('SELECT * FROM table')->fetchAll();
$paginator = new Paginator($rows, 20);//20=items per page

$offset = $_GET['page_number'];
$items = $paginator->getItemsForPage($offset);

if ($paginator->hasNextPage()) {
  echo "has next";
} else {
  echo "doesn't have next";
}

if ($paginator->hasPreviousPage()) {
  echo "has previous";
} else {
  echo "doesn't have previous";
}

foreach ($items as $item) {
  print_r($item);
}

[nade93]

thank for the suggestion, however I cannot get this to work!

[nade93]

managed to sort a solution!!! here it is incase anyone else needs it

 

<?php 
// Connects to your Database 
include('../../lib/conn.php');
//This checks to see if there is a page number. If not, it will set it to page 1 
if (!(isset($slideno))) 
{ 
$slideno = 1; 
} 

//Here we count the number of results 
//Edit $data to be your query 
$data = mysql_query("SELECT * FROM module_ws_slides where mod_no='5'") or die(mysql_error()); 
$rows = mysql_num_rows($data); 

//This is the number of results displayed per page 
$page_rows = 1; 

//This tells us the page number of our last page 
$last = ceil($rows/$page_rows); 

//this makes sure the page number isn't below one, or more than our maximum pages 
if ($slideno < 1) 
{ 
$slideno = 1; 
} 
elseif ($slideno > $last) 
{ 
$slideno = $last; 
} 

//This sets the range to display in our query 
$max = 'limit ' .($slideno - 1) * $page_rows .',' .$page_rows;

  //This is your query again, the same one... the only difference is we add $max into it
$data_p = mysql_query("SELECT * FROM module_ws_slides $max") or die(mysql_error()); 

//This is where you display your query results
while($info = mysql_fetch_array( $data_p )) 
{ 
Print $info['Name']; 


// First we check if we are on page one. If we are then we don't need a link to the previous page or the first page so we do nothing. If we aren't then we generate links to the first page, and to the previous page.
if ($slideno == 1) 
{
} 
else 
{
$previous = $slideno-1;
echo " <a href='{$_SERVER['PHP_SELF']}?slideno=$previous'> <img src=\"../img/layout/previous-arrow.png\" alt=\"previous slide\" border=\"0\" /></a> ";
} 


//This does the same as above, only checking if we are on the last page, and then generating the Next and Last links
if ($slideno == $last) 
{
} 
else {
$next = $slideno+1;
echo " <a href='{$_SERVER['PHP_SELF']}?slideno=$next'><img src=\"../img/layout/next-arrow.png\" alt=\"next slide\" border=\"0\" /></a> ";

} 
}
?>