Keep screen on during recording.

core/ui/src/main/java/org/signal/core/ui/compose/KeepScreenOnEffect.kt

@@ -5,22 +5,24 @@
 
 package org.signal.core.ui.compose
 
-import android.app.Activity
 import android.view.WindowManager
+import androidx.activity.compose.LocalActivity
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
-import androidx.compose.ui.platform.LocalContext
 
 /**
  * Keeps the screen on while this composable is in the composition by toggling
  * [WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON] on the host activity window.
+ *
+ * @param enabled When false, the flag is left alone, letting callers scope the effect to a piece of state without
+ *   having to conditionally compose it.
  */
 @Composable
-fun KeepScreenOnEffect() {
-  val context = LocalContext.current
+fun KeepScreenOnEffect(enabled: Boolean = true) {
+  val activity = LocalActivity.current
 
-  DisposableEffect(Unit) {
-    val window = (context as? Activity)?.window
+  DisposableEffect(activity, enabled) {
+    val window = if (enabled) activity?.window else null
     window?.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
 
     onDispose {

feature/camera/src/main/java/org/signal/camera/CameraScreen.kt

@@ -43,6 +43,7 @@ import androidx.lifecycle.compose.LocalLifecycleOwner
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import org.signal.core.ui.compose.AllNightPreviews
+import org.signal.core.ui.compose.KeepScreenOnEffect
 import org.signal.core.ui.compose.Previews
 import kotlin.time.Duration.Companion.milliseconds
 import androidx.camera.core.Preview as CameraPreview
@@ -92,6 +93,8 @@ fun CameraScreen(
 
   var surfaceRequest by remember { mutableStateOf<SurfaceRequest?>(null) }
 
+  KeepScreenOnEffect(enabled = state.isRecording)
+
   // Bind once; a screen rotation rebuilds just the preview (below), not the whole camera.
   LaunchedEffect(lifecycleOwner, state.lensFacing) {
     val cameraProvider = ProcessCameraProvider.getInstance(context).get()