From 211920bc7c4548c8efd64d78d469755539c06911 Mon Sep 17 00:00:00 2001
From: Bonian Chen <bonianchen@google.com>
Date: Thu, 2 Feb 2023 06:09:05 +0000
Subject: [PATCH] [Settings] Fix about phone crash no leave

Avoid from crash when LifecycleOwnerLiveData reports null during
destroy.

Bug: 267513122
Test: local

Change-Id: Ie541b0e5b81aa14bd064087c5343716b6bc066a3
---
 .../SimStatusPreferenceController.java        | 29 ++++++++++++++-----
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/src/com/android/settings/deviceinfo/simstatus/SimStatusPreferenceController.java b/src/com/android/settings/deviceinfo/simstatus/SimStatusPreferenceController.java
index ae002f342b8..828e016bdc7 100644
--- a/src/com/android/settings/deviceinfo/simstatus/SimStatusPreferenceController.java
+++ b/src/com/android/settings/deviceinfo/simstatus/SimStatusPreferenceController.java
@@ -24,6 +24,8 @@ import android.text.TextUtils;
 
 import androidx.annotation.VisibleForTesting;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LiveData;
 import androidx.lifecycle.Observer;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceCategory;
@@ -44,6 +46,7 @@ public class SimStatusPreferenceController extends BasePreferenceController {
 
     private Fragment mFragment;
     private SlotSimStatus mSlotSimStatus;
+    private Observer<LifecycleOwner> mLifecycleOwnerObserver;
     private Observer mSimChangeObserver;
 
     public SimStatusPreferenceController(Context context, String prefKey) {
@@ -112,13 +115,25 @@ public class SimStatusPreferenceController extends BasePreferenceController {
         if (mFragment == null) {
             return;
         }
-        final int simSlot = getSimSlotIndex();
-        if (mSimChangeObserver == null) {
-            mSimChangeObserver = x -> updateStateBySlot(preference, simSlot);
-            mFragment.getViewLifecycleOwnerLiveData().observeForever(lifecycleOwner -> {
-                mSlotSimStatus.observe(lifecycleOwner, mSimChangeObserver);
-            });
-        } else {
+        if (mLifecycleOwnerObserver == null) {
+            final LiveData<LifecycleOwner> dataLifecycleOwner
+                    = mFragment.getViewLifecycleOwnerLiveData();
+            mLifecycleOwnerObserver = owner -> {
+                if (owner != null) {
+                    final int simSlot = getSimSlotIndex();
+                    mSimChangeObserver = x -> updateStateBySlot(preference, simSlot);
+                    mSlotSimStatus.observe(owner, mSimChangeObserver);
+                } else {
+                    if (mSimChangeObserver != null) {
+                        mSlotSimStatus.removeObserver(mSimChangeObserver);
+                        mSimChangeObserver = null;
+                    }
+                    dataLifecycleOwner.removeObserver(mLifecycleOwnerObserver);
+                }
+            };
+            dataLifecycleOwner.observeForever(mLifecycleOwnerObserver);
+        } else if (mSimChangeObserver != null) {
+            final int simSlot = getSimSlotIndex();
             updateStateBySlot(preference, simSlot);
         }
     }