[Motion] Split-shade transition on LS: cross-fade status bars

Before, both the keyguard status bar and the split shade header
were showing at the same time during the shade expansion.

With this change, we make sure the keyguard status bar is faded
out before the split shade header fades in.

Fixes: 226548318
Test: Unit tests + Manually
Change-Id: I5757e7d6c065ee156030e434c19a965f8e1ef2f3

packages/SystemUI/src/com/android/systemui/statusbar/LockscreenShadeTransitionController.kt

@@ -494,6 +494,9 @@ class LockscreenShadeTransitionController @Inject constructor(
         }
         notificationPanelController
             .setKeyguardTransitionProgress(keyguardAlpha, keyguardTranslationY)
+
+        val statusBarAlpha = if (useSplitShade) keyguardAlpha else -1f
+        notificationPanelController.setKeyguardStatusBarAlpha(statusBarAlpha)
     }
 
     private fun setDragDownAmountAnimated(

packages/SystemUI/src/com/android/systemui/statusbar/phone/KeyguardStatusBarViewController.java

@@ -229,6 +229,11 @@ public class KeyguardStatusBarViewController extends ViewController<KeyguardStat
     private boolean mShowingKeyguardHeadsUp;
     private StatusBarSystemEventAnimator mSystemEventAnimator;
 
+    /**
+     * The alpha value to be set on the View. If -1, this value is to be ignored.
+     */
+    private float mExplicitAlpha = -1f;
+
     @Inject
     public KeyguardStatusBarViewController(
             KeyguardStatusBarView view,
@@ -425,9 +430,15 @@ public class KeyguardStatusBarViewController extends ViewController<KeyguardStat
 
         float alphaQsExpansion = 1 - Math.min(
                 1, mNotificationPanelViewStateProvider.getLockscreenShadeDragProgress() * 2);
-        float newAlpha = Math.min(getKeyguardContentsAlpha(), alphaQsExpansion)
-                * mKeyguardStatusBarAnimateAlpha
-                * (1.0f - mKeyguardHeadsUpShowingAmount);
+
+        float newAlpha;
+        if (mExplicitAlpha != -1) {
+            newAlpha = mExplicitAlpha;
+        } else {
+            newAlpha = Math.min(getKeyguardContentsAlpha(), alphaQsExpansion)
+                    * mKeyguardStatusBarAnimateAlpha
+                    * (1.0f - mKeyguardHeadsUpShowingAmount);
+        }
 
         boolean hideForBypass =
                 mFirstBypassAttempt && mKeyguardUpdateMonitor.shouldListenForFace()
@@ -510,7 +521,17 @@ public class KeyguardStatusBarViewController extends ViewController<KeyguardStat
     public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
         pw.println("KeyguardStatusBarView:");
         pw.println("  mBatteryListening: " + mBatteryListening);
+        pw.println("  mExplicitAlpha: " + mExplicitAlpha);
         mView.dump(fd, pw, args);
     }
 
+    /**
+     * Sets the alpha to be set on the view.
+     *
+     * @param alpha a value between 0 and 1. -1 if the value is to be reset/ignored.
+     */
+    public void setAlpha(float alpha) {
+        mExplicitAlpha = alpha;
+        updateViewState();
+    }
 }

packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelViewController.java

@@ -2682,6 +2682,15 @@ public class NotificationPanelViewController extends PanelViewController {
         updateClock();
     }
 
+    /**
+     * Sets the alpha value to be set on the keyguard status bar.
+     *
+     * @param alpha value between 0 and 1. -1 if the value is to be reset.
+     */
+    public void setKeyguardStatusBarAlpha(float alpha) {
+        mKeyguardStatusBarViewController.setAlpha(alpha);
+    }
+
     private void trackMovement(MotionEvent event) {
         if (mQsVelocityTracker != null) mQsVelocityTracker.addMovement(event);
     }

packages/SystemUI/tests/src/com/android/systemui/statusbar/LockscreenShadeTransitionControllerTest.kt

@@ -413,6 +413,28 @@ class LockscreenShadeTransitionControllerTest : SysuiTestCase() {
         verifyZeroInteractions(singleShadeOverScroller)
     }
 
+    @Test
+    fun setDragDownAmount_inSplitShade_setsKeyguardStatusBarAlphaBasedOnDistance() {
+        val alphaDistance = context.resources.getDimensionPixelSize(
+            R.dimen.lockscreen_shade_npvc_keyguard_content_alpha_transition_distance)
+        val dragDownAmount = 10f
+        enableSplitShade()
+
+        transitionController.dragDownAmount = dragDownAmount
+
+        val expectedAlpha = 1 - dragDownAmount / alphaDistance
+        verify(notificationPanelController).setKeyguardStatusBarAlpha(expectedAlpha)
+    }
+
+    @Test
+    fun setDragDownAmount_notInSplitShade_setsKeyguardStatusBarAlphaToMinusOne() {
+        disableSplitShade()
+
+        transitionController.dragDownAmount = 10f
+
+        verify(notificationPanelController).setKeyguardStatusBarAlpha(-1f)
+    }
+
     private fun enableSplitShade() {
         setSplitShadeEnabled(true)
     }

packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/KeyguardStatusBarViewControllerTest.java

@@ -343,6 +343,28 @@ public class KeyguardStatusBarViewControllerTest extends SysuiTestCase {
         assertThat(mKeyguardStatusBarView.getVisibility()).isEqualTo(View.INVISIBLE);
     }
 
+    @Test
+    public void setAlpha_explicitAlpha_setsExplicitAlpha() {
+        mController.onViewAttached();
+        updateStateToKeyguard();
+
+        mController.setAlpha(0.5f);
+
+        assertThat(mKeyguardStatusBarView.getAlpha()).isEqualTo(0.5f);
+    }
+
+    @Test
+    public void setAlpha_explicitAlpha_thenMinusOneAlpha_setsAlphaBasedOnDefaultCriteria() {
+        mController.onViewAttached();
+        updateStateToKeyguard();
+
+        mController.setAlpha(0.5f);
+        mController.setAlpha(-1f);
+
+        assertThat(mKeyguardStatusBarView.getAlpha()).isGreaterThan(0);
+        assertThat(mKeyguardStatusBarView.getAlpha()).isNotEqualTo(0.5f);
+    }
+
     // TODO(b/195442899): Add more tests for #updateViewState once CLs are finalized.
 
     @Test

packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/NotificationPanelViewControllerTest.java

@@ -938,6 +938,15 @@ public class NotificationPanelViewControllerTest extends SysuiTestCase {
         verify(mScrimController).setExpansionAffectsAlpha(true);
     }
 
+    @Test
+    public void setKeyguardStatusBarAlpha_setsAlphaOnKeyguardStatusBarController() {
+        float statusBarAlpha = 0.5f;
+
+        mNotificationPanelViewController.setKeyguardStatusBarAlpha(statusBarAlpha);
+
+        verify(mKeyguardStatusBarViewController).setAlpha(statusBarAlpha);
+    }
+
     private void triggerPositionClockAndNotifications() {
         mNotificationPanelViewController.closeQs();
     }