Meta boxes

This concept is based on WordPress functions.

You can add meta box from your-theme/functions/functions.php or in function boot of your plugin service provider.

Add a meta box

We need to add an action to hook BASE_ACTION_META_BOXES

Example:

add_action(BASE_ACTION_META_BOXES, 'callback_function_to_handle_meta_box', 120, 3);

Create callback for above action

/**
* This is an example callback function, it will add more fields to post create/edit screen.
*/
function callback_function_to_handle_meta_box($screen, $context)
{
    if (is_plugin_active('blog') && get_class($object) === \Botble\Blog\Models\Post::class && $context == 'advanced') {
        MetaBox::addMetaBox(
            'additional_post_fields',
            __('Addition Information'),
            'post_additional_fields',
            get_class($object),
            $context,
            'default'
        );
    }
}

Reference: https://developer.wordpress.org/reference/functions/add_meta_box.

Function: Adds a meta box to one or more screens.

add_meta_box(
    string $id, 
    string $title, 
    callable $callback, 
    string $class = null, 
    string $context = 'advanced', 
    string $priority = 'default', 
    array $callback_args = null
);

$id:

• (string) (Required) Meta box ID (used in the 'id' attribute for the meta box).

$title:

• (string) (Required) Title of the meta box.

$callback:

• (callable) (Required) Function that fills the box with the desired content. The function should echo its output.

$screen:

• (string|array|WP_Screen) (Optional) The screen or screens on which to show the box (such as a post type, 'link', or ' comment'). Accepts a single screen ID, WP_Screen object, or array of screen IDs. Default is the current screen.
• Default value: null

$context:

• (string) (Optional) The context within the screen where the boxes should display. Available contexts vary from screen to screen. Post edit screen contexts include 'normal', 'side', and 'advanced'. Comments screen contexts include ' normal' and 'side'. Menus meta boxes (accordion sections) all use the 'side' context. Global
• Default value: 'advanced'

$priority:

• (string) (Optional) The priority within the context where the boxes should show ('high', 'low').
• Default value: 'default'

$callback_args:

• (array) (Optional) Data that should be set as the $args property of the box array (which is the second parameter passed to your callback).
• Default value: null

Create callback function for add_meta_box function.

Example:

function post_additional_fields() {
    $videoLink = null;
    $args = func_get_args();

    if (! empty($args[0])) {
        $videoLink = MetaBox::getMetaData($args[0], 'video_link', true);
    }

    return Theme::partial('post-fields', compact('videoLink'));
}

You can see Theme::partial('post-field') so you need to create view for this function in your-theme/partials/post-fields.blade.php

<div class="form-group">
    <label for="video_link">{{ __('Video') }}</label>
    {!! Form::text('video_link', $video_link, ['class' => 'form-control', 'id' => 'video_link']) !!}
</div>

TIP

If you don't want to put view in your current theme, you can create that view in your plugin or resources/views then chang Theme::partial('post-field') to view('your-view')

Handle save meta box fields

Example:

add_action(BASE_ACTION_AFTER_CREATE_CONTENT, 'save_addition_post_fields', 230, 3);
add_action(BASE_ACTION_AFTER_UPDATE_CONTENT, 'save_addition_post_fields', 231, 3);

function save_addition_post_fields($type, $request, $object) {
    if (is_plugin_active('blog') && get_class($object) === \Botble\Blog\Models\Post::class) {
        MetaBox::saveMetaBoxData($object, 'video_link', $request->input('video_link'));
    }
}

Full example code.

** your-theme/functions/functions.php **

add_action(BASE_ACTION_META_BOXES, 'add_addition_fields_in_post_screen', 24, 2);

function add_addition_fields_in_post_screen($context, $object)
{
    if (is_plugin_active('blog') && get_class($object) == \Botble\Blog\Models\Post::class && $context == 'advanced') {
        MetaBox::addMetaBox('additional_post_fields', __('Addition Information'), 'post_additional_fields',
            get_class($object),
            $context,
            'default');
    }
}

function post_additional_fields() {
    $videoLink = null;
    $args = func_get_args();

    if (!empty($args[0])) {
        $videoLink = MetaBox::getMetaData($args[0], 'video_link', true);
    }

    return Theme::partial('post-fields', compact('videoLink'));
}

add_action(BASE_ACTION_AFTER_CREATE_CONTENT, 'save_addition_post_fields', 230, 3);
add_action(BASE_ACTION_AFTER_UPDATE_CONTENT, 'save_addition_post_fields', 231, 3);

function save_addition_post_fields($type, $request, $object) {
    if (is_plugin_active('blog') && get_class($object) == \Botble\Blog\Models\Post::class) {
        MetaBox::saveMetaBoxData($object, 'video_link', $request->input('video_link'));
    }
}

your-theme/partials/post-fields.blade.php

<div class="form-group">
    <label for="video-link">{{ __('Video') }}</label>
    {!! Form::text('video_link', $videoLink, ['class' => 'form-control', 'id' => 'video-link']) !!}
</div>