On phones, don't show the avatar icon when it is the only user.

The keyguard user switcher isn't enabled for layouts under 600dp width.
For these thinner devices, we don't show the multi-user switch view when
there is only one user.

In order to update this visibility when user changes occur, we
re-calculate the visibilities when the keyguard status bar view is
made visible again.

Bug: 28795981
Change-Id: I980a4c400adc1d9a6c0ce3465854284997e86596

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

@@ -56,6 +56,7 @@ public class KeyguardStatusBarView extends RelativeLayout
 
     private BatteryController mBatteryController;
     private KeyguardUserSwitcher mKeyguardUserSwitcher;
+    private UserSwitcherController mUserSwitcherController;
 
     private int mSystemIconsSwitcherHiddenExpandedMargin;
     private View mSystemIconsContainer;
@@ -149,6 +150,15 @@ public class KeyguardStatusBarView extends RelativeLayout
         } else if (mMultiUserSwitch.getParent() == this && mKeyguardUserSwitcherShowing) {
             removeView(mMultiUserSwitch);
         }
+        if (mKeyguardUserSwitcher == null) {
+            // If we have no keyguard switcher, the screen width is under 600dp. In this case,
+            // we don't show the multi-user avatar unless there is more than 1 user on the device.
+            if (mUserSwitcherController.getSwitchableUserCount() > 1) {
+                mMultiUserSwitch.setVisibility(View.VISIBLE);
+            } else {
+                mMultiUserSwitch.setVisibility(View.GONE);
+            }
+        }
         mBatteryLevel.setVisibility(mBatteryCharging ? View.VISIBLE : View.GONE);
     }
 
@@ -187,6 +197,7 @@ public class KeyguardStatusBarView extends RelativeLayout
     }
 
     public void setUserSwitcherController(UserSwitcherController controller) {
+        mUserSwitcherController = controller;
         mMultiUserSwitch.setUserSwitcherController(controller);
     }
 
@@ -287,6 +298,8 @@ public class KeyguardStatusBarView extends RelativeLayout
             mSystemIconsSuperContainer.animate().cancel();
             mMultiUserSwitch.animate().cancel();
             mMultiUserSwitch.setAlpha(1f);
+        } else {
+            updateVisibilities();
         }
     }
 

packages/SystemUI/src/com/android/systemui/statusbar/policy/UserSwitcherController.java

@@ -381,6 +381,18 @@ public class UserSwitcherController {
         Log.e(TAG, "Couldn't switch to user, id=" + userId);
     }
 
+    public int getSwitchableUserCount() {
+        int count = 0;
+        final int N = mUsers.size();
+        for (int i = 0; i < N; ++i) {
+            UserRecord record = mUsers.get(i);
+            if (record.info != null && record.info.supportsSwitchTo()) {
+                count++;
+            }
+        }
+        return count;
+    }
+
     private void switchToUserId(int id) {
         try {
             pauseRefreshUsers();