Foldables: detecting the fold

A Galaxy Z Fold or Flip reports its hinge as a FoldingFeature, one of the display features in WindowLayoutInfo from Jetpack WindowManager. It is not a window inset: the fold never changes systemBars or displayCutout, so pad for insets and lay out around the fold separately. Each feature has:

• state: FLAT (fully open) or HALF_OPENED (partly folded).
• orientation: VERTICAL for a book fold such as Galaxy Z Fold, HORIZONTAL for a clamshell such as Galaxy Z Flip.
• isSeparating: whether the fold splits the window into two logical areas. It is always true while HALF_OPENED.
• occlusionType: NONE or FULL, whether the fold hides part of the display.
• bounds: the fold's rectangle in window coordinates (px).

A closed device reports no folding feature. The app then runs on the cover display, which is a separate screen with its own insets. On this site, choose Cover or Main on a foldable's page to see each one.

The recordings below show what each posture reports as the hinge moves through 0°, the partly open range and 180°:

Recorded from this site's 3D renderer with the measured cover and inner displays. The angle where the animation turns from the cover to the inner display is illustrative; real devices switch displays at their own angle.

Compose Material 3 Adaptive (androidx.compose.material3.adaptive:adaptive) provides collectFoldingFeaturesAsState(), which recomposes whenever the fold changes. The posture checks below follow Android's Make your app fold aware guide.

@Composable
fun FoldAwareScreen() {
  val foldingFeatures by collectFoldingFeaturesAsState()
  val fold = foldingFeatures.firstOrNull()

  val isTabletop = fold?.state == FoldingFeature.State.HALF_OPENED &&
    fold.orientation == FoldingFeature.Orientation.HORIZONTAL
  val isBook = fold?.state == FoldingFeature.State.HALF_OPENED &&
    fold.orientation == FoldingFeature.Orientation.VERTICAL

  when {
    isTabletop -> TabletopLayout(foldBounds = fold!!.bounds) // content above, controls below
    isBook -> TwoPaneLayout(foldBounds = fold!!.bounds)      // one pane on each side
    else -> SinglePaneLayout()
  }
}

If you only need the posture, currentWindowAdaptiveInfoV2().windowPosture exposes it directly, for example windowPosture.isTabletop.

With Views, collect WindowInfoTracker (androidx.window:window) while the activity is started:

override fun onCreate(savedInstanceState: Bundle?) {
  super.onCreate(savedInstanceState)
  lifecycleScope.launch {
    repeatOnLifecycle(Lifecycle.State.STARTED) {
      WindowInfoTracker.getOrCreate(this@MainActivity)
        .windowLayoutInfo(this@MainActivity)
        .collect { layoutInfo ->
          val fold = layoutInfo.displayFeatures
            .filterIsInstance<FoldingFeature>()
            .firstOrNull()
          updateLayoutForFold(fold) // null when flat without a fold or closed
        }
    }
  }
}

FoldingFeature does not expose the angle. If you need it, read Sensor.TYPE_HINGE_ANGLE (API 30+) through SensorManager. Reporting ranges and accuracy vary by device, so prefer state and orientation for layout decisions. The hinge slider on this site's foldable pages is a visualization; the measured insets come from captures of the open and closed displays.

For design guidance on cover and inner screens, see Samsung's Designing for foldables, and for app-level patterns, Android's Learn about foldables.

Open an issue or pull request on GitHub. If you have a device and want to add insets data, use InsetsProbe and share your JSON.