PageSize.php

<?php

namespace backend\widgets;

use yii\helpers\Html;

/**
 * PageSize widget is an addition to the \yii\grid\GridView that enables
 * changing the size of a page on GridView.
 *
 * To use this widget with a GridView, add this widget to the page:
 * 
 * ~~~
 * <?php echo \backend\widgets\PageSize::widget(); ?>
 * ~~~
 *
 * and set the `filterSelector` property of GridView as shown in 
 * following example.
 *
 * ~~~
 * <?= GridView::widget([
 *      'dataProvider' => $dataProvider,
 *      'filterModel' => $searchModel,
 *	'filterSelector' => 'select[name="per-page"]',
 *      'columns' => [
 *          ...
 *      ],
 *  ]); ?>
 * ~~~
 *
 * Please note that `per-page` here is the string you use for `pageSizeParam` setting of the PageSize widget.
 */
class PageSize extends \yii\base\Widget
{
	/**
	 * @var string the label text.
	 */
	public $label = 'items';
	
	/**
	 * @var integer the defualt page size. This page size will be used when the $_GET['per-page'] is empty.
	 */
	public $defaultPageSize = 20;
	
	/**
	 * @var string the name of the GET request parameter used to specify the size of the page. 
	 * This will be used as the input name of the dropdown list with page size options.
	 */
	public $pageSizeParam = 'per-page';
	
	/**
	 * @var array the list of page sizes
	 */
	public $sizes = [2 => 2, 5 => 5, 10 => 10, 15 => 15, 20 => 20, 25 => 25, 50 => 50, 100 => 100, 200 => 200];
	
	/**
	 * @var string the template to be used for rendering the output.
	 */
	public $template = '{list} {label}';
	
	/**
	 * @var array the list of options for the drop down list.
	 */
	public $options;
	
	/**
	 * @var array the list of options for the label
	 */
	public $labelOptions;
	
	/**
	 * @var boolean whether to encode the label text.
	 */
	public $encodeLabel = true;
	
	/**
	 * Runs the widget and render the output
	 */
	public function run()
	{
		if(empty($this->options['id'])) {
			$this->options['id'] = $this->id;
			$this->options['class'] = 'form-control';
		}
		
		if($this->encodeLabel) {
			$this->label = Html::encode($this->label);
		}
		
		$perPage = !empty($_GET[$this->pageSizeParam]) ? $_GET[$this->pageSizeParam] : $this->defaultPageSize;
		
		$listHtml = Html::dropDownList($this->pageSizeParam, $perPage, $this->sizes, $this->options);
		$labelHtml = Html::label($this->label, $this->options['id'], $this->labelOptions);
		
		$output = str_replace(['{list}', '{label}'], [$listHtml, $labelHtml], $this->template);
		
		return $output;
	}
}