adaptive

Files (12)

• SKILL.md
• container-behavior.md · references/android/develop/ui/compose/layouts/adaptive/flexbox/
• get-started.md · references/android/develop/ui/compose/layouts/adaptive/flexbox/
• index.md · references/android/develop/ui/compose/layouts/adaptive/flexbox/
• item-behavior.md · references/android/develop/ui/compose/layouts/adaptive/flexbox/
• container-properties.md · references/android/develop/ui/compose/layouts/adaptive/grid/
• get-started.md · references/android/develop/ui/compose/layouts/adaptive/grid/
• index.md · references/android/develop/ui/compose/layouts/adaptive/grid/
• item-properties.md · references/android/develop/ui/compose/layouts/adaptive/grid/
• index.md · references/android/develop/ui/compose/layouts/adaptive/mediaquery/
• debug.md · references/android/develop/ui/compose/tooling/
• material-listdetail.md · references/android/guide/navigation/navigation-3/recipes/

SKILL.md (first lines)

## Prerequisites

The app must:

- Use Compose for all screens. If it's still using Fragments or Views, suggest using the XML to Compose skill to migrate those screens.
- Use Jetpack Navigation 3. If it doesn't, suggest the Navigation 3 skill to migrate the app.

## Workflow to make an app adaptive

To make an app adaptive, follow these steps or a subset of them adapting to the
task.

- Step 1: Verify current UI
- Step 2: Make the navigation bar adaptive
- Step 3: Add multi-pane layouts
- Step 4: Make vertical lists adaptive by changing the number of columns
- Step 5: Hide app bars when scrolling

## Step 1. Verify current UI

Ensure that screenshot tests exist to verify the current UI on different form
factors. If they don't exist, add the [Compose Preview Screenshot Testing
tool](references/android/develop/ui/compose/tooling/debug.md). Use the following annotation to create previews for all the major form
factors. For example:


```kotlin
@Preview(name = "Phone", device = Devices.PHONE, showBackground = true)
@Preview(name = "Foldable", device = Devices.FOLDABLE, showBackground = true)
@Preview(name = "Tablet", device = Devices.TABLET, showBackground = true)
@Preview(name = "Desktop", device = Devices.DESKTOP, showBackground = true)
annotation class FormFactorPreviews

@PreviewTest
@FormFactorPreviews
@Composable
fun FeedScreenPreview() {
    SnippetsTheme {
        Box {
            Text("My Screen")
        }
    }
}
```

<br />

## Step 2. Make the navigation bar adaptive

Bottom navigation bars are optimized for touch input when the user is holding a
phone in portrait mode. On larger screen hand-held devices, like tablets and
unfolded foldables, the navigation area must be accessible from the edge of the
screen (navigation rail).

If you need to provide more screen space for the content, hide the
navigation area. Examples of this include:

- Hiding the navigation bar when the user scrolls down and showing it again when the user scrolls up. The assumption is that when the user is scrolling down, they are consuming content but when scrolling up they are trying to navigate away from that content.
- Hiding the navigation area when its content is distracting. For example, in camera previews or when displaying a full-screen photo.

When the detail screen is displayed full-screen on mobile, full-screen mode must
be deactivated on larger screens.

Steps to migrate:

- Locate the existing navigation bar.
- Convert each item to a `NavigationSuiteItem`.
- Identify whether the navigation bar's visibility changes. For example, if it is wrapped with an `AnimatedContent` or `AnimatedVisibility` composable. If so, follow the guidance in the "Control navigation area visibility".
- Replace the container that held the navigation bar (often a `Scaffold`) with `NavigationSuiteScaffold` from the Material 3 adaptive layouts library.
- Supply the navigation items using the `navigationItems` parameter of `NavigationSuiteScaffold`.

### Step 2.1. Control navigation area visibility

If the navigation bar's visibility changes - it is hidden under certain
scenarios or on certain screens - this behavior must be maintained with the
adaptive navigation area. This is done using `NavigationSuiteScaffold`'s `state`
parameter.

Steps to migrate:

- Identify the scenarios under which the navigation bar is hidden. This is usually done with a boolean variable for the visibility. Use `isNavBarVisible` or `shouldShowNavBar` as the variable name.
- Create an instance of `NavigationSuiteScaffoldState` using `rememberNavigationSuiteScaffoldState()` and pass it to `NavigationSuiteScaffold`.
- When the navigation area visibility changes, use a `LaunchedEffect` to call `show` or `hide` on the `NavigationSuiteScaffoldState`.

For example:


```kotlin
// Pass this variable to any composable that needs to control the navigation area visibility
var isNavBarVisible by remember { mutableStateOf(true) }
val scaffoldVisibilityState = rememberNavigationSuiteScaffoldState()

NavigationSuiteScaffold(
    navigationSuiteItems = navItems,
    state = scaffoldVisibilityState
) {
    // Main content
}

LaunchedEffect(isNavBarVisible){
    if (isNavBarVisible) {
        scaffoldVisibilityState.show()
    } else {
        scaffoldVisibilityState.hide()
    }
}
```

<br />

## Step 3. Add multi-pane layouts using Navigation 3 Scenes

Analyze the codebase looking for related screens - tapping on something in one
screen opens another screen that shows information related to the first. There
are two canonical screen relationships: list-detail and supporting pane.

IMPORTANT: You must use the Navigation 3 `SceneStrategy` approach to implement
multi-pane layouts. Do not use `ListDetailPaneScaffold` or
`SupportingPaneScaffold`.

From IsKenKenYa/skills, GPL-3.0.

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