Placeholder Widgets

Page Builder supports the concept of placeholder widgets. These are widgets that your user might not have installed yet, but you'd like to encourage them to install.

Adding Widgets

Page Builder filters all widgets in the Add Widget dialog though the siteorigin_panels_widgets filter before displaying them. The following filter adds widgets that don't exist into the $widgets array.

function mytheme_recommended_widgets($widgets){
    if( empty($widgets['My_Custom_Widget']) ){
        $widgets['My_Custom_Widget'] = array(
            'class' => 'My_Custom_Widget',
            'title' => __('Custom Widget', 'siteorigin-panels'),
            'description' => __('My custom widget description', 'mytheme'),
            'installed' => false,
            'plugin' => array(
                'name' => __('Custom Widget Plugin', 'siteorigin-panels'),
                'slug' => 'plugin-slug'
            ),
            'groups' => array('recommended'),
            'icon' => 'dashicons dashicons-edit',
        );
    }

    return $widgets;
}
add_filter('siteorigin_panels_widgets', 'mytheme_recommended_widgets');

There's an optional 'plugin' attribute in the widget array. This tells Page Builder where it can download and install the plugin from, if it's hosted on the WordPress.org directory.

Rendering Missing Forms and Widgets

Page Builder gives you a few filters to deal with placeholder widgets. These are siteorigin_panels_missing_widget_form, siteorigin_panels_missing_widget and siteorigin_panels_widget_object.

Missing Widget Form

If Page Builder needs to render a form that doesn't exist, it'll pass the form HTML through the `` filter. It does this using the following form.

apply_filters('siteorigin_panels_missing_widget_form', $form, $widget, $instance);

Where $form is the current form HTML, $widget is the widget class and $instance is the widget instance. So, if you want to filter the HTML in your theme or plugin, you'll create a custom filter as follows.

function mytheme_filter_missing_widget_form($form, $widget, $instance){
    if( $widget === 'MyWidget_Class') {
        // This is our widget
        $form = mytheme_get_custom_missing_form($widget, $instance);
    }

    return $form;
}
add_filter('siteorigin_panels_missing_widget_form', 'mytheme_filter_missing_widget_form');

You can get creative here as to what you do with the widget form. You could go as far as creating the entire form.

Missing Widget Content

Page Builder also lets you create the frontend content for a widget using the siteorigin_panels_missing_widget filter. If Page Builder ever tries to render a form but there's no widget to do the rendering, it'll pass an empty string through this filter.

echo apply_filters('siteorigin_panels_missing_widget', '', $widget, $args , $instance);

Where the first argument is the empty string for you to populate, $widget is the widget class, $args are the widget arguments and $instance is the widget instance.

Here's an example of using a custom function to render a missing widget.

function mytheme_render_missing_widget($html, $widget, $args, $instance){
    if( $widget === 'MyWidget_Class') {
        $html = '';
        $html .= $args['before_widget'] . $args['before_title'] . $instance['title'] . $args['after_title'];
        $html .= ' ... ' // This is for more detailed form content.
        $html .= $args['after_widget'];
    }

    return $html;
}
add_filter('siteorigin_panels_missing_widget', 'mytheme_render_missing_widget');

Missing Widget Object

You could also simplify the whole process and just create a placeholder widget object. This widget should be of a class that extends the WP_Widget class.

This is how that filter is called.

$the_widget = apply_filters( 'siteorigin_panels_widget_object', $the_widget, $widget );

Where $the_widget is the widget object and $widget is the class name of the widget.

Here's an example of how you'd implement that.

class My_Placeholder_Widget extends WP_Widget {
    // Add all your widget stuff here.
}

function mytheme_filter_widget_object($the_widget, $widget) {
    if(empty($the_widget) && $widget == 'My_Placeholder_Widget') {
        $the_widget = new $widget();
    }

    return $the_widget;
}
add_filter('siteorigin_panels_widget_object', 'mytheme_filter_widget_object');