ButtonGroup.php

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\bootstrap;

use yii\helpers\ArrayHelper;

/**
 * ButtonGroup renders a button group bootstrap component.
 *
 * For example,
 *
 * ```php
 * // a button group with items configuration
 * echo ButtonGroup::widget([
 *     'buttons' => [
 *         ['label' => 'A'],
 *         ['label' => 'B'],
 *         ['label' => 'C', 'visible' => false],
 *     ]
 * ]);
 *
 * // button group with an item as a string
 * echo ButtonGroup::widget([
 *     'buttons' => [
 *         Button::widget(['label' => 'A']),
 *         ['label' => 'B'],
 *     ]
 * ]);
 * ```
 *
 * Pressing on the button should be handled via JavaScript. See the following for details:
 *
 * @see http://getbootstrap.com/javascript/#buttons
 * @see http://getbootstrap.com/components/#btn-groups
 *
 * @author Antonio Ramirez <amigo.cobos@gmail.com>
 * @since 2.0
 */
class ButtonGroup extends Widget
{
    /**
     * @var array list of buttons. Each array element represents a single button
     * which can be specified as a string or an array of the following structure:
     *
     * - label: string, required, the button label.
     * - options: array, optional, the HTML attributes of the button.
     * - visible: boolean, optional, whether this button is visible. Defaults to true.
     */
    public $buttons = [];
    /**
     * @var boolean whether to HTML-encode the button labels.
     */
    public $encodeLabels = true;


    /**
     * Initializes the widget.
     * If you override this method, make sure you call the parent implementation first.
     */
    public function init()
    {
        parent::init();
        Html::addCssClass($this->options, ['widget' => 'btn-group']);
    }

    /**
     * Renders the widget.
     */
    public function run()
    {
        BootstrapAsset::register($this->getView());
        return Html::tag('div', $this->renderButtons(), $this->options);
    }

    /**
     * Generates the buttons that compound the group as specified on [[buttons]].
     * @return string the rendering result.
     */
    protected function renderButtons()
    {
        $buttons = [];
        foreach ($this->buttons as $button) {
            if (is_array($button)) {
                $visible = ArrayHelper::remove($button, 'visible', true);
                if ($visible === false) {
                    continue;
                }

                $button['view'] = $this->getView();
                if (!isset($button['encodeLabel'])) {
                    $button['encodeLabel'] = $this->encodeLabels;
                }
                $buttons[] = Button::widget($button);
            } else {
                $buttons[] = $button;
            }
        }

        return implode("\n", $buttons);
    }
}