Use current alpha on PRIMARY_BOUNCER->LOCKSCREEN

This prevents a flicker if the user swipes up but then swipes
down right after.

Fixes: 359842276
Test: atest PrimaryBouncerToLockscreenTransitionViewModelTest
Flag: com.android.systemui.migrate_clocks_to_blueprint
Change-Id: I3d2a028532ae7ecc6a89d31fd154dead16687a79

4 files changed, 30 insertions, 3 deletions

diff --git a/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModelTest.kt b/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModelTest.kt
index 409c55144c6a..5ec566bab6d5 100644
--- a/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModelTest.kt
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModelTest.kt
@@ -28,6 +28,7 @@ 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.testKosmos
+import com.google.common.collect.Range
 import com.google.common.truth.Truth.assertThat
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.runCurrent
@@ -49,6 +50,24 @@ class PrimaryBouncerToLockscreenTransitionViewModelTest : SysuiTestCase() {
     val underTest = kosmos.primaryBouncerToLockscreenTransitionViewModel
 
     @Test
+    fun lockscreenAlphaStartsFromViewStateAccessorAlpha() =
+        testScope.runTest {
+            val viewState = ViewStateAccessor(alpha = { 0.5f })
+            val alpha by collectLastValue(underTest.lockscreenAlpha(viewState))
+
+            keyguardTransitionRepository.sendTransitionStep(step(0f, TransitionState.STARTED))
+
+            keyguardTransitionRepository.sendTransitionStep(step(0f))
+            assertThat(alpha).isEqualTo(0.5f)
+
+            keyguardTransitionRepository.sendTransitionStep(step(0.5f))
+            assertThat(alpha).isIn(Range.open(0.5f, 1f))
+
+            keyguardTransitionRepository.sendTransitionStep(step(1f))
+            assertThat(alpha).isEqualTo(1f)
+        }
+
+    @Test
     fun deviceEntryParentViewAlpha() =
         testScope.runTest {
             val deviceEntryParentViewAlpha by collectLastValue(underTest.deviceEntryParentViewAlpha)
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 050ef6f94f0a..06f77bfe54c6 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
@@ -270,7 +270,7 @@ constructor(
                         occludedToLockscreenTransitionViewModel.lockscreenAlpha,
                         primaryBouncerToAodTransitionViewModel.lockscreenAlpha,
                         primaryBouncerToGoneTransitionViewModel.lockscreenAlpha,
-                        primaryBouncerToLockscreenTransitionViewModel.lockscreenAlpha,
+                        primaryBouncerToLockscreenTransitionViewModel.lockscreenAlpha(viewState),
                     )
                     .onStart { emit(1f) }
             ) { hideKeyguard, alpha ->
diff --git a/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModel.kt b/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModel.kt
index 7511101bf04e..d29f5129bd59 100644
--- a/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModel.kt
+++ b/packages/SystemUI/src/com/android/systemui/keyguard/ui/viewmodel/PrimaryBouncerToLockscreenTransitionViewModel.kt
@@ -16,6 +16,7 @@
 
 package com.android.systemui.keyguard.ui.viewmodel
 
+import android.util.MathUtils
 import com.android.app.animation.Interpolators.EMPHASIZED_ACCELERATE
 import com.android.systemui.dagger.SysUISingleton
 import com.android.systemui.keyguard.domain.interactor.FromPrimaryBouncerTransitionInteractor
@@ -58,7 +59,14 @@ constructor(
             onStep = { it }
         )
 
-    val lockscreenAlpha: Flow<Float> = shortcutsAlpha
+    fun lockscreenAlpha(viewState: ViewStateAccessor): Flow<Float> {
+        var currentAlpha = 0f
+        return transitionAnimation.sharedFlow(
+            duration = 250.milliseconds,
+            onStart = { currentAlpha = viewState.alpha() },
+            onStep = { MathUtils.lerp(currentAlpha, 1f, it) },
+        )
+    }
 
     val deviceEntryBackgroundViewAlpha: Flow<Float> =
         transitionAnimation.immediatelyTransitionTo(1f)
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt
index 99f7a75676e1..f63ee7b9520d 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/ui/viewmodel/SharedNotificationContainerViewModel.kt
@@ -511,7 +511,7 @@ constructor(
                 occludedToAodTransitionViewModel.lockscreenAlpha,
                 occludedToGoneTransitionViewModel.notificationAlpha(viewState),
                 occludedToLockscreenTransitionViewModel.lockscreenAlpha,
-                primaryBouncerToLockscreenTransitionViewModel.lockscreenAlpha,
+                primaryBouncerToLockscreenTransitionViewModel.lockscreenAlpha(viewState),
                 glanceableHubToLockscreenTransitionViewModel.keyguardAlpha,
                 lockscreenToGlanceableHubTransitionViewModel.keyguardAlpha,
             )