Start Using Pagination

Using Pagination in Windwalker is very easy, but you must know how to count pages in your SQL.

A pagination always need 3 integers, Total rows, Items per page, and Current page.

For SQL and programming, this 3 integers will be Total, Limit, and Offset.

Count Total Rows

Some times we will fetch items from database by SQL which looks like this:

SELECT * 
FROM sakuras
WHERE state = 1
    AND author = 25
ORDER BY created
LIMIT 0, 20

This is a common way to count total rows by remove LIMIT element and select COUNT(*).

SELECT COUNT(*) 
FROM sakuras
WHERE state = 1
    AND author = 25
ORDER BY created

Use the second query we'll fetch total rows of first query without limit.

Another Way to Count Total

Use SQL_CALC_FOUND_ROWS in only MySQL.

SELECT SQL_CALC_FOUND_ROWS *
FROM sakuras
WHERE state = 1
    AND author = 25
ORDER BY created
LIMIT 0, 20

And use SELECT FOUND_ROWS() to fetch total rows, this way will a little faster than first way if you set index correctly , but only MySQL works.

Count Total if SQL has GROUP

If you add group in your SQL, the COUNT(*) will be incorrect, we must use an inefficient way to count all results.

This is the main query of yours.

SELECT *
FROM sakuras AS a
    LEFT JOIN flowers AS b ON a.flower_id = b.id
WHERE state = 1
    AND author = 25
ORDER BY created
LIMIT 0, 20
GROUP a.id

Remove LIMIT then execute this SQL:

SELECT *
FROM sakuras AS a
    LEFT JOIN flowers AS b ON a.flower_id = b.id
WHERE state = 1
    AND author = 25
ORDER BY created
GROUP a.id

And use ReaderCommand::count():

$total = $db->getReader($sql)->count();

Create Pagination

This is an example to fetch rows and total:

$limit = 20;
$page  = $input->get('page', 1);
$start = ($page - 1) * $limit;

$query = $db->getQuery(true);

// Basic query
$query->select('*')
    ->from('sakuras')
    ->where('state = 1')
    ->where('author = 25')
    ->order('created')
    ->limit($limit, $start);

// Load rows
$items = $db->getReader($query)->loadObjectList();

// Count total, clear non-necessary sql elements
$query->clear(array('select', 'limit', 'offset', 'order'))
    ->select('COUNT(*)');

$total = $db->getReader($query)->loadResult();

// Create pagination object
$pagination = new Pagination($total, $page, $limit);

// Get PaginationResult object
$paginData = $pagination->getResult();

Pagination Result

PaginationResult to an object contains pagination information, you can get pages data from this object:

$paginData = $pagination->getResult();

$paginData->getFirst();    // page number
$paginData->getLess();     // page number
$paginData->getPrevious(); // page number
$paginData->getPages();    // An array or pages
$paginData->getNext();     // page number
$paginData->getMore();     // page number
$paginData->getLast();     // page number

// Print all
print_r($paginData->getAll());

The output is:

Array
(
    [1] => first
    [7] => less
    [8] => lower
    [9] => lower
    [10] => lower
    [11] => lower
    [12] => current
    [13] => higher
    [14] => higher
    [15] => higher
    [16] => higher
    [17] => more
    [25] => last
)

You can use this array to build your pagination HTML.

pagination

UPagination Template

render() method will auto render pagination HTML, the default template is windwalker.pagination.default.

echo $pagination->render()

Set custom template:

$pagination->template('mytemplate.pagination', 'edge')->render();

Set custom route for building page URL.

$pagination->route('tag')->render();

// OR add package

$pagination->route('package@tag')->render();
````

Sometimes we may need more params in URL query:

``` php
$pagination->route('tag', ['title' => $title])->render();

Set Router object to Pagination if you have custom Router object.

echo $pagination->setRouter($router)
    ->route('tag', ['title' => $title])
    ->template('mytemplate.pagination', 'edge')
    ->render();

Simple Pagination

Windwalker supports simple pagination if you have a big table and you don't want to count totals.

// Use -1 as total.
echo (new Pagination($current, $limit, -1))
    ->template('windwalker.pagination.simple')
    ->render();

Or quick create by static:

echo Pagination::simple($current, $limit)->render();

If you found a typo or error, please help us improve this document.