From 8e12f5257d0f662431fec2bd5cddeb1c9acef76d Mon Sep 17 00:00:00 2001
From: lbill <lbill@google.com>
Date: Mon, 17 Apr 2023 11:41:55 +0000
Subject: [PATCH] Add Null check FingerprintSettings#updateAddPreference()

When fingerprint finish enrollment, user click Done
The flow would be:
-> wm_finish_activity
-> relaunch_resume_activity
-> wm_on_destroy_called
-> wm_on_create_called
-> wm_on_start_called
-> wm_on_activity_result_called
   In U, we need to add NPE check when updateAddPreference()
   earlier then addFingerprintItemPreferences()
-> wm_on_resume_called

Bug: 275519315
Test: manual enroll SFPS, in FingerprintEnrollEnrolling,
      rotate device, then complete the enrollment
      verify the flow never crash and user can see enrolled
      fingerprint in FingerprintSettings

Change-Id: Ia262741aeceeb36eefd159ad2ca1c9fa0e061d54
---
 .../biometrics/fingerprint/FingerprintSettings.java       | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/com/android/settings/biometrics/fingerprint/FingerprintSettings.java b/src/com/android/settings/biometrics/fingerprint/FingerprintSettings.java
index 59bbc1379e8..40a719a35d4 100644
--- a/src/com/android/settings/biometrics/fingerprint/FingerprintSettings.java
+++ b/src/com/android/settings/biometrics/fingerprint/FingerprintSettings.java
@@ -593,10 +593,16 @@ public class FingerprintSettings extends SubSettings {
         }
 
         private void updateAddPreference() {
-            if (getActivity() == null) return; // Activity went away
+            if (getActivity() == null) {
+                return; // Activity went away
+            }
 
             final Preference addPreference = findPreference(KEY_FINGERPRINT_ADD);
 
+            if (addPreference == null) {
+                return; // b/275519315 Skip if updateAddPreference() invoke before addPreference()
+            }
+
             /* Disable preference if too many fingerprints added */
             final int max = getContext().getResources().getInteger(
                     com.android.internal.R.integer.config_fingerprintMaxTemplatesPerUser);