📄Layouts & Menus

The layout component

Petal Pro gives the developer a <.layout> component, which takes a type attribute and renders a layout based on that type. eg:

<.layout current_page={:dashboard} current_user={@current_user} type="sidebar">
  <.container max_width="xl">
    <div>content</div>
  </.container>
</.layout>

It works by a simple case statement:

layout.ex

...
<%= case @type do %>
  <% "sidebar" -> %>
    <.sidebar_layout {assigns}>
      ...
    </.sidebar_layout>
  <% "stacked" -> %>
    <.stacked_layout {assigns}>
      ...
    </.stacked_layout>
  <% "public" -> %>
    <.public_layout {assigns}>
      ...
    </.public_layout>
<% end %>
...

You can maintain this file and add/remove layouts as you please.

How to modify an existing layout

Petal Pro provides a number of layouts: "sidebar", "stacked" and "public". These are quite configurable however you may want to modify them. To do so, you can simply duplicate the layout file from the petal_framework library into your /components directory and change the module name. How to do that?

Firstly, let's take a look at all the components in Petal Framework. While in your project directory, run this command:

# this assumes you're using vscode:
code deps/petal_framework/lib/petal_framework/web/components

This will open a new VSCode instance with all the Petal Framework components. Here you can see the sidebar_layout.ex file.

Copy sidebar_layout.ex to <your_app>_web/components/
Change the module name from PetalFramework.Components.SidebarLayout to YourAppWeb.Components.SidebarLayout
In core_components.ex add an import statement to import your module, e.g. import YourAppWeb.Components.SidebarLayout
You will notice that due to the existing use PetalFramework the application would no longer compile correctly, simply rename the function in your new layout, e.g. from sidebar_layout to myapp_sidebar_layout
Go back to core_components.ex and rename sidebar_layout to myapp_sidebar_layout
Now when you call <.layout type="sidebar"> it will render your duplicate layout instead, and you can modify it to however you like

How to add a new layout

Create a new file in <you_app>_web/components , eg: my_cool_layout.ex
Look at what assigns other layouts like sidebar.ex use - you can see in layout.ex how menu items are passed in, as well as the user's name and avatar
When complete, you can import your layout into layout.ex and modify the layout/1 function - eg:

<%= case @type do %>
  <% "my-cool-layout" -> %>
    <.my_cool_layout {assigns}>

4. Now in your template or live view file, you simply update the type to your new layout:

<.layout type="my-cool-layout" current_page={:dashboard} current_user={@current_user}>
  <.container>
    <div>content</div>
  </.container>
</.layout>

Petal Pro Layouts

Sidebar layout

This is the typical web application layout. It allows for a large number of menu items on the sidebar.

<.layout current_page={:dashboard} current_user={@current_user} type="sidebar">
  <.container>
    <div>content</div>
  </.container>
</.layout>

Stacked layout

A stacked layout with a navbar and then content.

<.layout current_page={:dashboard} current_user={@current_user} type="stacked">
  <.container max_width="xl">
    <div>content</div>
  </.container>
</.layout>e

Public layout

Includes a header and footer - for use in public facing, marketing pages.

<.layout 
  type="public" 
  current_user={assigns[:current_user]} 
  current_page={:landing} 
  max_width="sm|md|lg|xl|full"
>

</.layout>

Menus

In menus.ex there is a list of all the menu items. This can be useful when working with navbars and layouts, where you sometimes need to loop over menu items multiple times.

For all menu items, you must define a new get_link/2 function, which takes a name and current_user as the parameters. The name parameter is pattern matched and thus you statically include it in the function definition. A menu item has a name, label, path and icon. Here's an example of a menu item for the "Register" menu item:

def get_link(:register, _current_user) do
  %{
    name: :register,
    label: "Register",
    path: Routes.user_registration_path(Endpoint, :new),
    icon: :clipboard_list
  }
end

You can use the current_user param to conditionally display a menu item. For example, here we don't show the menu item unless the user is an admin.

def get_link(:admin_users = name, current_user) do
  if Helpers.is_admin?(current_user) do
    %{
      name: name,
      label: "Users",
      path: Routes.admin_users_path(Endpoint, :index),
      icon: :users
    }
  else
    nil
  end
end

You can build menu item lists to give to layouts. We define the two core menu lists in menus.ex:

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