Canonical layouts are proven, versatile layouts that provide an optimal user
experience on a variety of form factors.

![Depiction of large screen devices showing the canonical layouts.](https://developer.android.com/static/develop/ui/compose/images/layouts/adaptive/canonical-layouts/canonical_layouts_header.png)

The canonical layouts support small screen phones as well as tablets, foldables,
and ChromeOS devices. Derived from [Material Design guidance](https://m3.material.io/foundations/layout/canonical-layouts/overview), the layouts are
aesthetic as well as functional.

The Android framework includes specialized components that make implementation
of the layouts straightforward and reliable.

The canonical layouts create engaging, productivity‑enhancing UIs that
form the foundation of great apps.

## List-detail

![Wireframe of list-detail layout.](https://developer.android.com/static/develop/ui/compose/images/layouts/adaptive/canonical-layouts/list-detail_wireframe.png)

The list-detail layout enables users to explore lists of items that have
descriptive, explanatory, or other supplementary information---the item
detail.

The layout divides the app window into two side-by-side panes: one for the list,
one for the detail. Users select items from the list to display the item detail.
Deep links in the detail reveal additional content in the detail pane.

Expanded-width displays (see [Use window size classes](https://developer.android.com/develop/ui/compose/layouts/adaptive/use-window-size-classes)) accommodate both the
list and detail at the same time. Selection of a list item updates the detail
pane to show the related content for the selected item.

Medium- and compact-width displays show either the list or the detail, depending
on user interaction with the app. When just the list is visible, selection of a
list item displays the detail in place of the list. When just the detail is
visible, pressing the back button redisplays the list.

Configuration changes such as device orientation changes or app window size
changes can change the display's window size class. A list‑detail layout
responds accordingly, preserving app state:

- If an expanded-width display showing both the list and detail panes narrows to medium or compact, the detail pane remains visible and the list pane is hidden
- If a medium- or compact-width display has just the detail pane visible and the window size class widens to expanded, the list and detail are shown together, and the list indicates that the item corresponding to the content in the detail pane is selected
- If a medium- or compact-width display has just the list pane visible and widens to expanded, the list and a placeholder detail pane are shown together

List-detail is ideal for [messaging apps](https://developer.android.com/large-screens/gallery/social#media), [contact managers](https://developer.android.com/large-screens/gallery/productivity#items-and-overviews), [interactive
media browsers](https://developer.android.com/large-screens/gallery/media#easy-exploration) or any app where the content can be organized as a list of
items that reveal additional information.
Your browser doesn't support the video tag. **Figure 1.** Messaging app showing a list of conversations and the details of a selected conversation.

### Implementation

The declarative paradigm of Compose supports window size class logic that
determines whether to show the list and detail panes at the same time (when the
width window size class is expanded) or just the list or detail pane (when the
width window size class is medium or compact).

To ensure unidirectional data flow, [hoist all state](https://developer.android.com/jetpack/compose/state#state-hoisting), including current
window size class and detail of the selected list item (if any), so all
composables have access to the data and can render correctly.

When showing just the detail pane on small window sizes, add a [`BackHandler`](https://developer.android.com/reference/kotlin/androidx/activity/compose/package-summary#BackHandler(kotlin.Boolean,kotlin.Function0))
to remove the detail pane and display just the list pane. The `BackHandler` is
not part of the overall app navigation since the handler is dependent on the
window size class and selected detail state.

For an example implementation, see the [List-detail with Compose](https://github.com/android/adaptive-apps-samples/tree/main/CanonicalLayouts/list-detail-compose)
sample.

## Feed

![Wireframe of feed layout.](https://developer.android.com/static/develop/ui/compose/images/layouts/adaptive/canonical-layouts/feed_wireframe.png)

A feed layout arranges equivalent content elements in a configurable grid for
quick, convenient viewing of a large amount of content.

Size and position establish relationships among the content elements.

Content groups are created by making elements the same size and positioning them
together. Attention is drawn to elements by making them larger than nearby
elements.

Cards and lists are common components of feed layouts.

A feed layout supports displays of almost any size because the grid can adapt
from a single, scrolling column to a multi‑column scrolling feed of
content.

Feeds are especially well suited for [news and social media apps](https://developer.android.com/large-screens/gallery/social#posts).
Your browser doesn't support the video tag. **Figure 2.** Social media app showing posts in cards of varying sizes.

### Implementation

A feed consists of a large number of content elements in a vertical scrolling
container laid out in a grid. [Lazy lists](https://developer.android.com/jetpack/compose/lists#lazy) efficiently render a large number
of items in columns or rows. [Lazy grids](https://developer.android.com/jetpack/compose/lists#lazy-grids) render items in grids, supporting
configuration of the item sizes and spans.

Configure the columns of the grid layout based on the available display area to
set the minimum allowable width for grid items. When defining grid items, adjust
column spans to emphasize some items over others.

For section headers, dividers, or other items designed to occupy the full width
of the feed, use [`maxLineSpan`](https://developer.android.com/reference/kotlin/androidx/compose/foundation/lazy/grid/LazyGridItemSpanScope#maxLineSpan()) to take up the full width of the layout.

On compact-width displays that don't have enough space to show more than one
column, [`LazyVerticalGrid`](https://developer.android.com/reference/kotlin/androidx/compose/foundation/lazy/grid/package-summary#LazyVerticalGrid(androidx.compose.foundation.lazy.grid.GridCells,androidx.compose.ui.Modifier,androidx.compose.foundation.lazy.grid.LazyGridState,androidx.compose.foundation.layout.PaddingValues,kotlin.Boolean,androidx.compose.foundation.layout.Arrangement.Vertical,androidx.compose.foundation.layout.Arrangement.Horizontal,androidx.compose.foundation.gestures.FlingBehavior,kotlin.Boolean,kotlin.Function1)) behaves just like a [`LazyColumn`](https://developer.android.com/reference/kotlin/androidx/compose/foundation/lazy/package-summary#LazyColumn(androidx.compose.ui.Modifier,androidx.compose.foundation.lazy.LazyListState,androidx.compose.foundation.layout.PaddingValues,kotlin.Boolean,androidx.compose.foundation.layout.Arrangement.Vertical,androidx.compose.ui.Alignment.Horizontal,androidx.compose.foundation.gestures.FlingBehavior,kotlin.Boolean,kotlin.Function1)).

For an example implementation, see the [Feed with Compose](https://github.com/android/adaptive-apps-samples/tree/main/CanonicalLayouts/feed-compose)
sample.

<br />

## Supporting pane

![Wireframe of supporting pane layout.](https://developer.android.com/static/develop/ui/compose/images/layouts/adaptive/canonical-layouts/supporting_pane_wireframe.png)

Supporting pane layout organizes app content into primary and secondary display
areas.

The primary display area occupies the majority of the app window (typically
about two thirds) and contains the main content. The secondary display area is a
pane that takes up the remainder of the app window and presents content that
supports the main content.

Supporting pane layouts work well on expanded-width displays (see [Use window
size classes](https://developer.android.com/develop/ui/compose/layouts/adaptive/use-window-size-classes)) in landscape orientation. Medium- or compact‑width
displays support showing both the primary and secondary display areas if the
content is adaptable to narrower display spaces, or if the additional content
can be initially hidden in a bottom or side sheet accessible by means of a
control such as a menu or button.

A supporting pane layout differs from a list‑detail layout in the
relationship of the primary and secondary content. Secondary pane content is
meaningful only in relation to the primary content; for example, a supporting
pane tool window is irrelevant by itself. The supplementary content in the
detail pane of a list‑detail layout, however, is meaningful even without
the primary content, for example, the description of a product from a product
listing.

Use cases for supporting pane include:

- **Productivity apps:** A [document or spreadsheet accompanied by reviewer
  comments](https://developer.android.com/large-screens/gallery/productivity#reviews-and-comments) in a supporting pane
- **Media apps:** A [streaming video complemented by a list of related videos](https://developer.android.com/large-screens/gallery/media#media-exploration) in a supporting pane, or the depiction of an album of music supplemented with a playlist
- **Tools and settings:** A [media editing tool](https://developer.android.com/large-screens/gallery/social#tools) with palettes, effects, and other settings in a support pane

Your browser doesn't support the video tag. **Figure 3.** Shopping app with product descriptions in a supporting pane.

### Implementation

Compose supports window size class logic, which enables you to determine whether
to show both the main content and the supporting content at the same time or
place the supporting content in an alternative location.

Hoist all state, including current window size class and information related to
the data in the main content and supporting content.

For compact-width displays, place the supporting content below the main content
or inside a bottom sheet. For medium and expanded widths, place the supporting
content next to the main content, sized appropriately based on the content and
space available. For medium width, split the display space equally between the
main and supporting content. For expanded width, give 70% of the space to the
main content, 30% to the supporting content.

For an example implementation, see the [Supporting pane with
Compose](https://github.com/android/adaptive-apps-samples/tree/main/CanonicalLayouts/supporting-pane-compose) sample.

## Additional resources

- Material Design --- [Canonical layouts](https://m3.material.io/foundations/layout/canonical-layouts/overview)