规范布局

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.

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.

如果您对自适应应用规范化布局很熟悉，但不确定哪些 Android API 适用于您的应用，请跳转到适用性部分，该部分可帮助您确定哪种布局适用于您的应用用例。

List-detail

Wireframe of list-detail layout.

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.

Figure 1. Messaging app showing a list of conversations and the details of a selected conversation.

Implementation

您可以使用各种技术创建列表-详情布局，包括 Compose、View 和 activity 嵌入（适用于旧版应用）。如需我们帮助您确定哪项技术最适用于您的应用，请参阅适用性部分。

SlidingPaneLayout 库旨在基于 View 或 fragment 实现列表详情布局。

首先，将 SlidingPaneLayout 声明为 XML 布局的根元素。接下来，添加两个子元素（View 或 fragment），用于表示列表和详情内容。

实现一种通信方法，以便在列表-详情 View 或 fragment 之间传递数据。建议使用 ViewModel，因为它能存储业务逻辑，并且可在配置更改后继续留存。

SlidingPaneLayout 会自动判断列表和详情应该同时显示还是单独显示。如果窗口的横向空间足够同时容纳列表和详情，二者会并排显示。如果窗口空间不足，系统会根据用户与应用的互动单独显示列表或详情。

如需查看示例实现，请参阅包含滑动窗格的列表-详情示例。

activity 嵌入

借助 activity 嵌入，可以让旧版的多 activity 应用在同一屏幕中并排显示两个 activity，或让两个 activity 堆叠显示（一个叠加在另一个之上）。如果您的应用在单独的 activity 中分别实现列表详情布局的列表和详情，借助 activity 嵌入，您只需进行少量代码重构（甚至无需重构），即可创建列表详情布局。

如需实现 activity 嵌入，只需使用 XML 配置文件指定任务窗口拆分即可。分屏定义了主要 activity（用于启动分屏）和辅助 activity。使用窗口大小类别断点指定拆分的显示屏宽度下限。当显示屏宽度低于断点下限时，activity 便会叠加显示。例如，如果显示屏宽度下限为 600dp，那么在较小宽度的显示屏上，activity 会叠加显示；但在中等宽度和较大宽度的显示屏上，activity 会并排显示。

Android 12L（API 级别 32）及更高版本支持 activity 嵌入，但经设备制造商实现后，较低的 API 级别也可提供相应支持。如果设备不支持 activity 嵌入，回退行为会导致列表 activity 或详情 activity 占据整个应用窗口，具体取决于用户与应用的互动。

如需了解详情，请参阅 activity 嵌入。

如需查看示例实现，请参阅使用 activity 嵌入构建列表详情示例。

Feed

Wireframe of feed layout.

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.

Figure 2. Social media app showing posts in cards of varying sizes.

Implementation

A RecyclerView efficiently renders a large number of items in a single column. A GridLayoutManager lays out items in a grid, allowing configuration of the item sizes and spans.

Configure the grid columns based on the size of the available display area to set the minimum allowable width for items.

The GridLayoutManager default spanning strategy, which is one span per item, can be overridden by creating a custom SpanSizeLookup. Adjust the span to emphasize some items over others.

On compact-width displays that have enough space for only one column, use LinearLayoutManager instead of GridLayoutManager.

For an example implementation, see the Feed with views sample.

Supporting pane

Wireframe of supporting pane layout.

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
Figure 3. Shopping app with product descriptions in a supporting pane.

Implementation

辅助窗格布局是使用 LinearLayout 或 ConstraintLayout 等辅助布局实现的。建立窗口大小类别 用于将应用可用的横向显示空间量 三个类别：较小 (< 600dp)、中等 (>= 600dp) 和较大 (>= 840dp)。

针对每个窗口大小类别，按以下方式定义布局：

  • 紧凑：在应用资源 layout 文件夹中，放置 在主要内容下方或底部动作条内呈现辅助窗格
  • 中等：在 layout-w600dp 文件夹中提供辅助窗格内容，使主要内容和辅助窗格并排呈现，并平均分配横向显示空间
  • 展开：在 layout-w840dp 文件夹中添加辅助窗格内容，使主要内容和辅助窗格并排呈现；不过，让辅助窗格只占据横向空间的 30%，并将其余 70% 的空间留给主要内容

使用 ViewModel 在主要内容和 无论是使用 View、fragment 还是二者结合使用，都可以在辅助窗格中显示。

如需查看实现示例，请参阅以下示例：

适用性

规范布局可对内容进行多层面的展示，以便于访问和深入发掘。您可以利用以下流程图来确定哪种布局和实现策略最适用于您的应用用例。

如需查看在不同类型的应用中实现的规范化布局的示例，请参阅大屏幕图库。

图 4. 大屏幕规范布局决策树。

Additional resources