Remove setalpha(0f) from reset.

Reset has too many callers for different reasons. It is extremely frail
and is causing the user switcher to disappear for various reasons.
Largely the user switcher disappears when switching users in the bouncer
and persisting the bouncer.

Fixes: 290355544
Test: Get multiple users and switch users with bouncer user switcher on.
Test: close and open bouncer scrimmed to see that the userswitcher does
not flicker.

Change-Id: I313240f1c594d5df6071b0dc6a7099496990e274

packages/SystemUI/src/com/android/keyguard/KeyguardSecurityContainerController.java

@@ -676,6 +676,14 @@ public class KeyguardSecurityContainerController extends ViewController<Keyguard
         mSecurityViewFlipperController.reset();
     }
 
+    /** Prepares views in the bouncer before starting appear animation. */
+    public void prepareToShow() {
+        View bouncerUserSwitcher = mView.findViewById(R.id.keyguard_bouncer_user_switcher);
+        if (bouncerUserSwitcher != null) {
+            bouncerUserSwitcher.setAlpha(0f);
+        }
+    }
+
     @Override
     public void onResume(int reason) {
         if (DEBUG) Log.d(TAG, "screen on, instance " + Integer.toHexString(hashCode()));

packages/SystemUI/src/com/android/systemui/bouncer/ui/binder/KeyguardBouncerViewBinder.kt

@@ -120,6 +120,8 @@ object KeyguardBouncerViewBinder {
                         viewModel.isShowing.collect { isShowing ->
                             view.visibility = if (isShowing) View.VISIBLE else View.INVISIBLE
                             if (isShowing) {
+                                // Reset security container because these views are not reinflated.
+                                securityContainerController.prepareToShow()
                                 securityContainerController.reinflateViewFlipper {
                                     // Reset Security Container entirely.
                                     securityContainerController.onBouncerVisibilityChanged(

packages/SystemUI/tests/src/com/android/keyguard/KeyguardSecurityContainerControllerTest.kt

@@ -27,6 +27,7 @@ import android.testing.TestableResources
 import android.view.Gravity
 import android.view.LayoutInflater
 import android.view.MotionEvent
+import android.view.View
 import android.view.WindowInsetsController
 import android.widget.FrameLayout
 import androidx.test.filters.SmallTest
@@ -80,6 +81,7 @@ import org.mockito.Captor
 import org.mockito.Mock
 import org.mockito.Mockito.atLeastOnce
 import org.mockito.Mockito.clearInvocations
+import org.mockito.Mockito.mock
 import org.mockito.Mockito.never
 import org.mockito.Mockito.spy
 import org.mockito.Mockito.verify
@@ -772,6 +774,16 @@ class KeyguardSecurityContainerControllerTest : SysuiTestCase() {
             verify(viewMediatorCallback).keyguardDone(anyBoolean(), anyInt())
         }
 
+    @Test
+    fun testResetUserSwitcher() {
+        val userSwitcher = mock(View::class.java)
+        whenever(view.findViewById<View>(R.id.keyguard_bouncer_user_switcher))
+            .thenReturn(userSwitcher)
+
+        underTest.prepareToShow()
+        verify(userSwitcher).setAlpha(0f)
+    }
+
     private val registeredSwipeListener: KeyguardSecurityContainer.SwipeListener
         get() {
             underTest.onViewAttached()