Kanonische Layouts

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.

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

Compose 的声明性范式支持用于作出如下判断的窗口大小类别逻辑:同时显示列表窗格和详情窗格(当宽度窗口大小类别为较大时),还是只显示列表窗格或详情窗格(当宽度窗口大小类别为中等或较小时)。

为确保单向数据流,请提升所有状态,包括当前窗口大小类别和所选列表项的详细信息(如果有),以便所有可组合项都可以访问相应数据并进行正确的呈现。

当小窗口中只显示详情窗格时,添加 BackHandler 即可移除详情窗格并转为只显示列表窗格。BackHandler 不是应用整体导航的一部分,因为处理程序取决于窗口大小类别和所选详情状态。

如需查看示例实现,请参阅使用 Compose 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

Ein Feed besteht aus einer großen Anzahl von Inhaltselementen in einem vertikal scrollbaren Container, der in einem Raster angeordnet ist. Lazy-Listen rendern eine große Anzahl von Elementen in Spalten oder Zeilen effizient. Lazy-Grids rendern Elemente in Rastern und unterstützen die Konfiguration der Elementgrößen und ‑abstände.

Konfigurieren Sie die Spalten des Rasterlayouts basierend auf dem verfügbaren Anzeigebereich, um die zulässige Mindestbreite für Rasterelemente festzulegen. Passen Sie beim Definieren von Rasterelementen die Spaltenspanne an, um einige Elemente stärker hervorzuheben als andere.

Verwenden Sie maxLineSpan für Abschnittsüberschriften, Trennlinien oder andere Elemente, die die gesamte Breite des Feeds einnehmen sollen.

Auf Displays mit kleiner Breite, auf denen nicht genügend Platz zur Anzeige von mehr als einer Spalte vorhanden ist, verhält sich LazyVerticalGrid wie ein LazyColumn.

Eine Beispielimplementierung finden Sie im Beispiel Feed mit Compose.

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

Compose unterstützt die Fenstergrößenklassenlogik, mit der Sie festlegen können, ob sowohl der Hauptinhalt als auch die unterstützenden Inhalte gleichzeitig angezeigt werden sollen oder ob die unterstützenden Inhalte an einem anderen Ort platziert werden sollen.

Gesamten Status hochziehen, einschließlich der aktuellen Fenstergrößenklasse und Informationen zu den Daten im Hauptinhalt und unterstützenden Inhalten.

Bei kompakter Breite platzieren Sie die unterstützenden Inhalte unter dem Hauptinhalt oder in einem Tabellenblatt am unteren Rand. Bei mittlerer und erweiterter Breite platzieren Sie die unterstützenden Inhalte neben dem Hauptinhalt und passen die Größe entsprechend den Inhalten und dem verfügbaren Platz an. Bei mittlerer Breite sollten Sie den Displaybereich gleichmäßig auf Haupt- und unterstützende Inhalte aufteilen. Bei der erweiterten Breite sollten 70% des Platzes für die Hauptinhalte und 30% für die unterstützenden Inhalte vorgesehen werden.

Eine Beispielimplementierung finden Sie im Beispiel Supporting pane with Compose (Unterstützungsbereich mit Compose).

Additional resources