Advanced Custom Fields Plugin

ACF (Pro) is a WordPress plugin which allows you to create custom key/value storage fields on WordPress posts.

By default, every WordPress Post has a title and a content text field. For complex pages or custom post types however you may wish to use multiple and specific fields. (eg A custom post type ‘book’ might have a field ‘ISBN Number’)

If you’re already familiar with the ACF Plugin, you may skip this chapter.

ACF Components

Below is an overview of the ACF Structure. More detailed information about individual components in the following chapters.

• Field Groups

  • Field 0..n

  • Repeater Field

    • Field 0..n

  • Flexible Content Field

    • Layout 0..n

      • Field 0..n

The repeater and flexible layout fields are just there for reference. Of course they are regular fields and fit wherever a field fits. That is, inside a field group, layout or repeater field. Putting a flexible content field inside a repeater field, inside a layout of a flexible content field, inside a ...etc is probably a bad idea. Think about splitting stuff into multiple field groups and creating custom post types.

Field Groups

The basic ACF building block is a field group. Field groups are a container in which you may add fields. Field groups also specify where its fields are attached.

So you might create a ‘bookfieldgroup’ with a field for an ISBN Number, and configure this field group to attach itself to posts of the type book.

Fields

A field is a key/value storage. There are simple fields like the TextField for storing strings, and complex fields like the RelationShipField for storing foreign keys or the RepeaterField and FlexibleContentField, which are used for repeating elements. More on these complex fields below.

Repeater Fields

Repeater fields can have fields added to itself.

The perfect example is building an image slider. You’d create a repeater field called slider. To this repeater field you can then add the image field ‘image’ and the textarea field ‘caption’. This would provide you with a structure in which you can add multiple “slides”, each consisting of an image and a caption field, to your slider.

Flexible Content Fields & Layouts

Whereas repeater fields are perfect for sliders, flexible layout fields are perfect for user-generated content where they can choose from pre-defined layouts, and add, delete and arrange them in any way they desire. So instead of adding fields to a flexible content field, you add layouts.

You can think of layouts as “mini field groups”, because they can hold fields like a field group, but are always attached to a specific flexible content field.

A perfect example is a standard content page on any website. By creating a flexible content field, you can add a paragraph layout(title field and text field), an image layout(image field and alt text field), a gallery layout(with a repeater field), and so on. The user can then decide if and in which order they use the layouts.