Canonical layouts are proven, versatile layouts that provide an optimal user experience on a variety of form factors.
The canonical layouts support small screen phones as well as tablets, foldables, and ChromeOS devices. Derived from Material Design guidance, 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
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) 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, contact managers, file browsers, or any app where the content can be organized as a list of items that reveal additional information.
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, 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
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 sample.
Feed
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.
Implementation
動態提醒是由垂直捲動容器中的大量內容元素組成，以格線配置。Lazy 清單能夠有效率地在多欄或多列中算繪大量項目。Lazy 格線會在格線中算繪項目，支援項目大小和跨距的設定。
請根據可用的螢幕區域調整格線版面配置欄，設定格線項目的最小寬度。定義格線項目時，調整欄的跨距以強調部分項目。
如果是區段標題、分隔線或其他占用動態消息最大寬度的項目，請使用 maxLineSpan 占用版面配置的最大寬度。
如果寬度較窄的螢幕沒有足夠空間顯示多欄，LazyVerticalGrid 的運作方式會與 LazyColumn 一樣。
如需實作範例，請參閱「使用 Compose 建立動態提醒」範例。
Supporting pane
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) 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 in a supporting pane
- Media apps: A streaming video complemented by a list of related videos in a supporting pane, or the depiction of an album of music supplemented with a playlist
- Search and reference apps: A query input form with results in a supporting pane
Implementation
Compose 支援視窗大小類別邏輯，可讓您判斷要同時顯示主要內容和輔助內容，或將輔助內容放在替代位置。
提升所有狀態，包括目前視窗大小類別，以及主要內容和輔助內容資料的相關資訊。
如果是寬度較窄的螢幕，請將輔助內容放在主要內容下方或底部功能表中。如果是中等和展開寬度，請將輔助內容放在主要內容旁，並根據可用的內容和空間適當調整大小。如果是中等寬度，請將顯示空間平均分配給主要內容和輔助內容。如果是展開寬度，請將 70% 的空間留給主要內容，30% 分給輔助內容。
如需實作範例，請參閱「使用 Compose 建立輔助窗格」範例。
Additional resources
- Material Design — Canonical layouts