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Workaround for blank camera preview when switching to tabletop mode #4

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Merged
temcguir merged 1 commit into from
May 14, 2025
Merged

Workaround for blank camera preview when switching to tabletop mode #4

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17 changes: 17 additions & 0 deletions feature/camera/src/main/java/com/android/developers/androidify/camera/CameraScreen.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@ import androidx.compose.runtime.mutableFloatStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.runtime.setValue
import androidx.compose.runtime.snapshotFlow
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.geometry.Offset
Expand All @@ -70,6 +71,7 @@ import com.google.accompanist.permissions.ExperimentalPermissionsApi
import com.google.accompanist.permissions.isGranted
import com.google.accompanist.permissions.rememberPermissionState
import com.google.accompanist.permissions.shouldShowRationale
import kotlinx.coroutines.flow.takeWhile
import kotlinx.coroutines.launch

@OptIn(
Expand Down Expand Up @@ -129,6 +131,21 @@ fun CameraPreviewScreen(
}

uiState.surfaceRequest?.let { surface ->
// Workaround for https://issuetracker.google.com/275157240
// When switching to/from tabletop posture, the underlying SurfaceView
// destroys its Surface. Invalidate the SurfaceRequest when this happens
// so CameraX can retrieve the new Surface.
LaunchedEffect(surface) {
val oldIsTableTop = isTableTopPosture(foldingFeature)
snapshotFlow { foldingFeature }
.takeWhile {
val newIsTableTop = isTableTopPosture(it)
val shouldInvalidate = oldIsTableTop != newIsTableTop
if (shouldInvalidate) surface.invalidate()
!shouldInvalidate
}.collect {}
}

CameraPreviewContent(
surfaceRequest = surface,
autofocusUiState = uiState.autofocusUiState,
Expand Down