Resetting workspace alpha when the animation is cancelled

Bug: 364465567
Test: Manual
Flag: EXEMPT bug fix
Change-Id: I0dcc62a10ca96670c5ed794001c58fd319e36854
diff --git a/quickstep/src/com/android/quickstep/util/ScalingWorkspaceRevealAnim.kt b/quickstep/src/com/android/quickstep/util/ScalingWorkspaceRevealAnim.kt
index db02f55..f719bed 100644
--- a/quickstep/src/com/android/quickstep/util/ScalingWorkspaceRevealAnim.kt
+++ b/quickstep/src/com/android/quickstep/util/ScalingWorkspaceRevealAnim.kt
@@ -217,6 +217,11 @@
         animation.addListener(
             AnimatorListeners.forEndCallback(
                 Runnable {
+                    // The workspace might stay at a transparent state when the animation is
+                    // cancelled, and the alpha will not be recovered (this doesn't apply to scales
+                    // somehow). Resetting the alpha for the workspace here.
+                    workspace.alpha = 1.0F
+
                     workspace.setLayerType(View.LAYER_TYPE_NONE, null)
                     hotseat.setLayerType(View.LAYER_TYPE_NONE, null)