Merge "Transform and consolidate transitionValue() API" into main

8 files changed, 130 insertions, 100 deletions

diff --git a/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModelTest.kt b/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModelTest.kt
index 49df345397d4..194f362d984c 100644
--- a/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModelTest.kt
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModelTest.kt
@@ -39,7 +39,9 @@ import com.android.systemui.keyguard.shared.model.KeyguardState
 import com.android.systemui.keyguard.shared.model.TransitionState
 import com.android.systemui.keyguard.shared.model.TransitionStep
 import com.android.systemui.kosmos.testScope
+import com.android.systemui.scene.data.repository.Idle
 import com.android.systemui.scene.data.repository.sceneContainerRepository
+import com.android.systemui.scene.data.repository.setSceneTransition
 import com.android.systemui.scene.shared.flag.SceneContainerFlag
 import com.android.systemui.scene.shared.model.Scenes
 import com.android.systemui.shade.shadeTestUtil
@@ -290,6 +292,7 @@ class KeyguardRootViewModelTest(flags: FlagsParameterization) : SysuiTestCase()
                 testScope,
             )
 
+            kosmos.setSceneTransition(Idle(Scenes.Gone))
             // Make sure the value hasn't changed since we're GONE
             keyguardRepository.topClippingBounds.value = 5
             assertThat(topClippingBounds).isEqualTo(1000)
@@ -518,11 +521,14 @@ class KeyguardRootViewModelTest(flags: FlagsParameterization) : SysuiTestCase()
                 to = KeyguardState.GONE,
                 testScope = testScope,
             )
+            kosmos.setSceneTransition(Idle(Scenes.Gone))
             assertThat(alpha).isEqualTo(0f)
 
-            // Try pulling down shade and ensure the value doesn't change
-            shadeTestUtil.setQsExpansion(0.5f)
-            assertThat(alpha).isEqualTo(0f)
+            if (!SceneContainerFlag.isEnabled) {
+                // Try pulling down shade and ensure the value doesn't change
+                shadeTestUtil.setQsExpansion(0.5f)
+                assertThat(alpha).isEqualTo(0f)
+            }
         }
 
     @Test
diff --git a/packages/SystemUI/multivalentTests/src/com/android/systemui/scene/domain/interactor/SceneInteractorTest.kt b/packages/SystemUI/multivalentTests/src/com/android/systemui/scene/domain/interactor/SceneInteractorTest.kt
index 881ce413a022..92e6b16e5001 100644
--- a/packages/SystemUI/multivalentTests/src/com/android/systemui/scene/domain/interactor/SceneInteractorTest.kt
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/scene/domain/interactor/SceneInteractorTest.kt
@@ -21,16 +21,19 @@ package com.android.systemui.scene.domain.interactor
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.filters.SmallTest
 import com.android.compose.animation.scene.ObservableTransitionState
+import com.android.compose.animation.scene.SceneKey
 import com.android.systemui.SysuiTestCase
 import com.android.systemui.coroutines.collectLastValue
 import com.android.systemui.flags.EnableSceneContainer
 import com.android.systemui.keyguard.data.repository.fakeDeviceEntryFingerprintAuthRepository
 import com.android.systemui.keyguard.shared.model.SuccessFingerprintAuthenticationStatus
 import com.android.systemui.kosmos.testScope
+import com.android.systemui.scene.data.repository.Idle
+import com.android.systemui.scene.data.repository.Transition
 import com.android.systemui.scene.data.repository.sceneContainerRepository
+import com.android.systemui.scene.data.repository.setSceneTransition
 import com.android.systemui.scene.sceneContainerConfig
 import com.android.systemui.scene.sceneKeys
-import com.android.systemui.scene.shared.model.SceneContainerConfig
 import com.android.systemui.scene.shared.model.SceneFamilies
 import com.android.systemui.scene.shared.model.Scenes
 import com.android.systemui.scene.shared.model.fakeSceneDataSource
@@ -54,48 +57,27 @@ class SceneInteractorTest : SysuiTestCase() {
     private val testScope = kosmos.testScope
     private val fakeSceneDataSource = kosmos.fakeSceneDataSource
 
-    private lateinit var underTest: SceneInteractor
+    private val underTest = kosmos.sceneInteractor
 
     @Test
     fun allSceneKeys() {
-        underTest = kosmos.sceneInteractor
         assertThat(underTest.allSceneKeys()).isEqualTo(kosmos.sceneKeys)
     }
 
     @Test
     fun changeScene_toUnknownScene_doesNothing() =
         testScope.runTest {
-            val sceneKeys =
-                listOf(
-                    Scenes.QuickSettings,
-                    Scenes.Shade,
-                    Scenes.Lockscreen,
-                    Scenes.Gone,
-                    Scenes.Communal,
-                )
-            val navigationDistances =
-                mapOf(
-                    Scenes.Gone to 0,
-                    Scenes.Lockscreen to 0,
-                    Scenes.Communal to 1,
-                    Scenes.Shade to 2,
-                    Scenes.QuickSettings to 3,
-                )
-            kosmos.sceneContainerConfig =
-                SceneContainerConfig(sceneKeys, Scenes.Lockscreen, navigationDistances)
-            underTest = kosmos.sceneInteractor
             val currentScene by collectLastValue(underTest.currentScene)
+            val unknownScene = SceneKey("UNKNOWN")
             val previousScene = currentScene
-            assertThat(previousScene).isNotEqualTo(Scenes.Bouncer)
-            underTest.changeScene(Scenes.Bouncer, "reason")
+            assertThat(previousScene).isNotEqualTo(unknownScene)
+            underTest.changeScene(unknownScene, "reason")
             assertThat(currentScene).isEqualTo(previousScene)
         }
 
     @Test
     fun changeScene() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
-
             val currentScene by collectLastValue(underTest.currentScene)
             assertThat(currentScene).isEqualTo(Scenes.Lockscreen)
 
@@ -106,8 +88,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun changeScene_toGoneWhenUnl_doesNotThrow() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
-
             val currentScene by collectLastValue(underTest.currentScene)
             assertThat(currentScene).isEqualTo(Scenes.Lockscreen)
 
@@ -122,15 +102,11 @@ class SceneInteractorTest : SysuiTestCase() {
 
     @Test(expected = IllegalStateException::class)
     fun changeScene_toGoneWhenStillLocked_throws() =
-        testScope.runTest {
-            underTest = kosmos.sceneInteractor
-            underTest.changeScene(Scenes.Gone, "reason")
-        }
+        testScope.runTest { underTest.changeScene(Scenes.Gone, "reason") }
 
     @Test
     fun changeScene_toGoneWhenTransitionToLockedFromGone() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val currentScene by collectLastValue(underTest.currentScene)
             val transitionTo by collectLastValue(underTest.transitioningTo)
             kosmos.sceneContainerRepository.setTransitionState(
@@ -155,7 +131,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun changeScene_toHomeSceneFamily() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val currentScene by collectLastValue(underTest.currentScene)
 
             underTest.changeScene(SceneFamilies.Home, "reason")
@@ -167,37 +142,17 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun snapToScene_toUnknownScene_doesNothing() =
         testScope.runTest {
-            val sceneKeys =
-                listOf(
-                    Scenes.QuickSettings,
-                    Scenes.Shade,
-                    Scenes.Lockscreen,
-                    Scenes.Gone,
-                    Scenes.Communal,
-                )
-            val navigationDistances =
-                mapOf(
-                    Scenes.Gone to 0,
-                    Scenes.Lockscreen to 0,
-                    Scenes.Communal to 1,
-                    Scenes.Shade to 2,
-                    Scenes.QuickSettings to 3,
-                )
-            kosmos.sceneContainerConfig =
-                SceneContainerConfig(sceneKeys, Scenes.Lockscreen, navigationDistances)
-            underTest = kosmos.sceneInteractor
             val currentScene by collectLastValue(underTest.currentScene)
             val previousScene = currentScene
-            assertThat(previousScene).isNotEqualTo(Scenes.Bouncer)
-            underTest.snapToScene(Scenes.Bouncer, "reason")
+            val unknownScene = SceneKey("UNKNOWN")
+            assertThat(previousScene).isNotEqualTo(unknownScene)
+            underTest.snapToScene(unknownScene, "reason")
             assertThat(currentScene).isEqualTo(previousScene)
         }
 
     @Test
     fun snapToScene() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
-
             val currentScene by collectLastValue(underTest.currentScene)
             assertThat(currentScene).isEqualTo(Scenes.Lockscreen)
 
@@ -208,8 +163,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun snapToScene_toGoneWhenUnl_doesNotThrow() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
-
             val currentScene by collectLastValue(underTest.currentScene)
             assertThat(currentScene).isEqualTo(Scenes.Lockscreen)
 
@@ -224,15 +177,11 @@ class SceneInteractorTest : SysuiTestCase() {
 
     @Test(expected = IllegalStateException::class)
     fun snapToScene_toGoneWhenStillLocked_throws() =
-        testScope.runTest {
-            underTest = kosmos.sceneInteractor
-            underTest.snapToScene(Scenes.Gone, "reason")
-        }
+        testScope.runTest { underTest.snapToScene(Scenes.Gone, "reason") }
 
     @Test
     fun snapToScene_toHomeSceneFamily() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val currentScene by collectLastValue(underTest.currentScene)
 
             underTest.snapToScene(SceneFamilies.Home, "reason")
@@ -244,7 +193,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun sceneChanged_inDataSource() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val currentScene by collectLastValue(underTest.currentScene)
             assertThat(currentScene).isEqualTo(Scenes.Lockscreen)
 
@@ -256,14 +204,14 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun transitionState() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
-            val underTest = kosmos.sceneContainerRepository
+            val sceneContainerRepository = kosmos.sceneContainerRepository
             val transitionState =
                 MutableStateFlow<ObservableTransitionState>(
                     ObservableTransitionState.Idle(Scenes.Lockscreen)
                 )
-            underTest.setTransitionState(transitionState)
-            val reflectedTransitionState by collectLastValue(underTest.transitionState)
+            sceneContainerRepository.setTransitionState(transitionState)
+            val reflectedTransitionState by
+                collectLastValue(sceneContainerRepository.transitionState)
             assertThat(reflectedTransitionState).isEqualTo(transitionState.value)
 
             val progress = MutableStateFlow(1f)
@@ -284,7 +232,7 @@ class SceneInteractorTest : SysuiTestCase() {
             progress.value = 0.9f
             assertThat(reflectedTransitionState).isEqualTo(transitionState.value)
 
-            underTest.setTransitionState(null)
+            sceneContainerRepository.setTransitionState(null)
             assertThat(reflectedTransitionState)
                 .isEqualTo(
                     ObservableTransitionState.Idle(kosmos.sceneContainerConfig.initialSceneKey)
@@ -294,7 +242,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun transitioningTo() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val transitionState =
                 MutableStateFlow<ObservableTransitionState>(
                     ObservableTransitionState.Idle(underTest.currentScene.value)
@@ -332,7 +279,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun isTransitionUserInputOngoing_idle_false() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val transitionState =
                 MutableStateFlow<ObservableTransitionState>(
                     ObservableTransitionState.Idle(Scenes.Shade)
@@ -347,7 +293,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun isTransitionUserInputOngoing_transition_true() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val transitionState =
                 MutableStateFlow<ObservableTransitionState>(
                     ObservableTransitionState.Transition(
@@ -369,7 +314,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun isTransitionUserInputOngoing_updateMidTransition_false() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val transitionState =
                 MutableStateFlow<ObservableTransitionState>(
                     ObservableTransitionState.Transition(
@@ -403,7 +347,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun isTransitionUserInputOngoing_updateOnIdle_false() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val transitionState =
                 MutableStateFlow<ObservableTransitionState>(
                     ObservableTransitionState.Transition(
@@ -429,7 +372,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun isVisible() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val isVisible by collectLastValue(underTest.isVisible)
             assertThat(isVisible).isTrue()
 
@@ -443,7 +385,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun isVisible_duringRemoteUserInteraction_forcedVisible() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             underTest.setVisible(false, "reason")
             val isVisible by collectLastValue(underTest.isVisible)
             assertThat(isVisible).isFalse()
@@ -458,7 +399,6 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun resolveSceneFamily_home() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             assertThat(underTest.resolveSceneFamily(SceneFamilies.Home))
                 .isEqualTo(kosmos.homeSceneFamilyResolver.resolvedScene)
         }
@@ -466,8 +406,46 @@ class SceneInteractorTest : SysuiTestCase() {
     @Test
     fun resolveSceneFamily_nonFamily() =
         testScope.runTest {
-            underTest = kosmos.sceneInteractor
             val resolved = underTest.resolveSceneFamily(Scenes.Gone).toList()
             assertThat(resolved).containsExactly(Scenes.Gone).inOrder()
         }
+
+    @Test
+    fun transitionValue_test_idle() =
+        testScope.runTest {
+            val transitionValue by collectLastValue(underTest.transitionProgress(Scenes.Gone))
+
+            kosmos.setSceneTransition(Idle(Scenes.Gone))
+            assertThat(transitionValue).isEqualTo(1f)
+
+            kosmos.setSceneTransition(Idle(Scenes.Lockscreen))
+            assertThat(transitionValue).isEqualTo(0f)
+        }
+
+    @Test
+    fun transitionValue_test_transitions() =
+        testScope.runTest {
+            val transitionValue by collectLastValue(underTest.transitionProgress(Scenes.Gone))
+            val progress = MutableStateFlow(0f)
+
+            kosmos.setSceneTransition(
+                Transition(from = Scenes.Lockscreen, to = Scenes.Gone, progress = progress)
+            )
+            assertThat(transitionValue).isEqualTo(0f)
+
+            progress.value = 0.4f
+            assertThat(transitionValue).isEqualTo(0.4f)
+
+            kosmos.setSceneTransition(
+                Transition(from = Scenes.Gone, to = Scenes.Lockscreen, progress = progress)
+            )
+            progress.value = 0.7f
+            assertThat(transitionValue).isEqualTo(0.3f)
+
+            kosmos.setSceneTransition(
+                Transition(from = Scenes.Lockscreen, to = Scenes.Shade, progress = progress)
+            )
+            progress.value = 0.9f
+            assertThat(transitionValue).isEqualTo(0f)
+        }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/keyguard/data/repository/KeyguardTransitionRepository.kt b/packages/SystemUI/src/com/android/systemui/keyguard/data/repository/KeyguardTransitionRepository.kt
index 8ec460a7088f..1b201ceda310 100644
--- a/packages/SystemUI/src/com/android/systemui/keyguard/data/repository/KeyguardTransitionRepository.kt
+++ b/packages/SystemUI/src/com/android/systemui/keyguard/data/repository/KeyguardTransitionRepository.kt
@@ -20,6 +20,7 @@ import android.animation.AnimatorListenerAdapter
 import android.animation.ValueAnimator
 import android.animation.ValueAnimator.AnimatorUpdateListener
 import android.annotation.FloatRange
+import android.annotation.SuppressLint
 import android.os.Trace
 import android.util.Log
 import com.android.app.tracing.coroutines.withContext
@@ -117,10 +118,11 @@ class KeyguardTransitionRepositoryImpl
 constructor(
     @Main val mainDispatcher: CoroutineDispatcher,
 ) : KeyguardTransitionRepository {
-    /*
-     * Each transition between [KeyguardState]s will have an associated Flow.
-     * In order to collect these events, clients should call [transition].
+    /**
+     * Each transition between [KeyguardState]s will have an associated Flow. In order to collect
+     * these events, clients should call [transition].
      */
+    @SuppressLint("SharedFlowCreation")
     private val _transitions =
         MutableSharedFlow<TransitionStep>(
             replay = 2,
diff --git a/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardInteractor.kt b/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardInteractor.kt
index 73835a3c1c96..48660f25907a 100644
--- a/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardInteractor.kt
+++ b/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardInteractor.kt
@@ -50,7 +50,7 @@ import com.android.systemui.shade.data.repository.ShadeRepository
 import com.android.systemui.statusbar.CommandQueue
 import com.android.systemui.statusbar.notification.NotificationUtils.interpolate
 import com.android.systemui.statusbar.notification.stack.domain.interactor.SharedNotificationContainerInteractor
-import com.android.systemui.util.kotlin.Utils.Companion.sample as sampleCombine
+import com.android.systemui.util.kotlin.Utils.Companion.sampleFilter
 import com.android.systemui.util.kotlin.pairwise
 import com.android.systemui.util.kotlin.sample
 import javax.inject.Inject
@@ -77,6 +77,7 @@ import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.merge
 import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.flow.stateIn
+import com.android.systemui.util.kotlin.Utils.Companion.sample as sampleCombine
 
 /**
  * Encapsulates business-logic related to the keyguard but not to a more specific part within it.
@@ -91,7 +92,7 @@ constructor(
     bouncerRepository: KeyguardBouncerRepository,
     configurationInteractor: ConfigurationInteractor,
     shadeRepository: ShadeRepository,
-    keyguardTransitionInteractor: KeyguardTransitionInteractor,
+    private val keyguardTransitionInteractor: KeyguardTransitionInteractor,
     sceneInteractorProvider: Provider<SceneInteractor>,
     private val fromGoneTransitionInteractor: Provider<FromGoneTransitionInteractor>,
     private val fromLockscreenTransitionInteractor: Provider<FromLockscreenTransitionInteractor>,
@@ -248,21 +249,17 @@ constructor(
     val isKeyguardGoingAway: Flow<Boolean> = repository.isKeyguardGoingAway
 
     /** Keyguard can be clipped at the top as the shade is dragged */
-    val topClippingBounds: Flow<Int?> =
-        combineTransform(
-                configurationInteractor.onAnyConfigurationChange,
+    val topClippingBounds: Flow<Int?> by lazy {
+        repository.topClippingBounds
+            .sampleFilter(
                 keyguardTransitionInteractor
-                    .transitionValue(GONE)
-                    .map { it == 1f }
-                    .onStart { emit(false) }
-                    .distinctUntilChanged(),
-                repository.topClippingBounds
-            ) { _, isGone, topClippingBounds ->
-                if (!isGone) {
-                    emit(topClippingBounds)
-                }
+                    .transitionValue(scene = Scenes.Gone, stateWithoutSceneContainer = GONE)
+                    .onStart { emit(0f) }
+            ) { goneValue ->
+                goneValue != 1f
             }
             .distinctUntilChanged()
+    }
 
     /** Last point that [KeyguardRootView] view was tapped */
     val lastRootViewTapPosition: Flow<Point?> = repository.lastRootViewTapPosition.asStateFlow()
diff --git a/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardTransitionInteractor.kt b/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardTransitionInteractor.kt
index 2766b71fae02..2c12945bb0cd 100644
--- a/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardTransitionInteractor.kt
+++ b/packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardTransitionInteractor.kt
@@ -223,6 +223,17 @@ constructor(
         }
     }
 
+    fun transitionValue(
+        scene: SceneKey,
+        stateWithoutSceneContainer: KeyguardState,
+    ): Flow<Float> {
+        return if (SceneContainerFlag.isEnabled) {
+            sceneInteractor.get().transitionProgress(scene)
+        } else {
+            transitionValue(stateWithoutSceneContainer)
+        }
+    }
+
     /**
      * The amount of transition into or out of the given [KeyguardState].
      *
@@ -232,6 +243,10 @@ constructor(
     fun transitionValue(
         state: KeyguardState,
     ): Flow<Float> {
+        if (SceneContainerFlag.isEnabled && state != state.mapToSceneContainerState()) {
+            Log.e(TAG, "SceneContainer is enabled but a deprecated state $state is used.")
+            return transitionValue(state.mapToSceneContainerScene()!!, state)
+        }
         return getTransitionValueFlow(state)
     }
 
diff --git a/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModel.kt b/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModel.kt
index ee52ad024e24..5027524e7a4b 100644
--- a/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModel.kt
+++ b/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/KeyguardRootViewModel.kt
@@ -203,7 +203,7 @@ constructor(
         combine(
                 communalInteractor.isIdleOnCommunal,
                 keyguardTransitionInteractor
-                    .transitionValue(GONE)
+                    .transitionValue(scene = Scenes.Gone, stateWithoutSceneContainer = GONE)
                     .map { it == 1f }
                     .onStart { emit(false) },
                 keyguardTransitionInteractor
diff --git a/packages/SystemUI/src/com/android/systemui/scene/domain/interactor/SceneInteractor.kt b/packages/SystemUI/src/com/android/systemui/scene/domain/interactor/SceneInteractor.kt
index 2f66d6bb7be1..998537c98f8d 100644
--- a/packages/SystemUI/src/com/android/systemui/scene/domain/interactor/SceneInteractor.kt
+++ b/packages/SystemUI/src/com/android/systemui/scene/domain/interactor/SceneInteractor.kt
@@ -156,6 +156,28 @@ constructor(
             )
 
     /**
+     * The amount of transition into or out of the given [scene].
+     *
+     * The value will be `0` if not in this scene or `1` when fully in the given scene.
+     */
+    fun transitionProgress(scene: SceneKey): Flow<Float> {
+        return transitionState.flatMapLatest { transition ->
+            when (transition) {
+                is ObservableTransitionState.Idle -> {
+                    flowOf(if (transition.currentScene == scene) 1f else 0f)
+                }
+                is ObservableTransitionState.Transition -> {
+                    when {
+                        transition.toScene == scene -> transition.progress
+                        transition.fromScene == scene -> transition.progress.map { 1f - it }
+                        else -> flowOf(0f)
+                    }
+                }
+            }
+        }
+    }
+
+    /**
      * Returns the keys of all scenes in the container.
      *
      * The scenes will be sorted in z-order such that the last one is the one that should be
diff --git a/packages/SystemUI/src/com/android/systemui/util/kotlin/Utils.kt b/packages/SystemUI/src/com/android/systemui/util/kotlin/Utils.kt
index 405b57a1a04d..2f9fb0115eb7 100644
--- a/packages/SystemUI/src/com/android/systemui/util/kotlin/Utils.kt
+++ b/packages/SystemUI/src/com/android/systemui/util/kotlin/Utils.kt
@@ -19,6 +19,8 @@ package com.android.systemui.util.kotlin
 import android.content.Context
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.filter
+import kotlinx.coroutines.flow.map
 
 class Utils {
     companion object {
@@ -50,6 +52,14 @@ class Utils {
             )
 
         /**
+         * Samples the provided flow, performs a filter on the sampled value, then returns the
+         * original value.
+         */
+        fun <A, B> Flow<A>.sampleFilter(b: Flow<B>, predicate: (B) -> Boolean): Flow<A> {
+            return this.sample(b, ::Pair).filter { (_, b) -> predicate(b) }.map { (a, _) -> a }
+        }
+
+        /**
          * Samples the provided flows, emitting a tuple of the original flow's value as well as each
          * of the combined flows' values.
          *