From dc5e10e3ccd2b536b08dfe81481c743ddb75b044 Mon Sep 17 00:00:00 2001
From: Becca Hughes <beccahughes@google.com>
Date: Fri, 8 Sep 2023 14:08:04 -0700
Subject: [PATCH] Add a couple of guards to make sure crash doesn't happen

This adds two guards, first checking when the provider
list is generated to stop and flag an warning, second
to have PackageMonitor use a handler so callbacks should
only happen on the thread that the fragment is running
on and if that is no longer available it won't do
anything.

Test: ondevice
Bug: 296164461
Change-Id: Iab03f8a10e667694e2e23da7574831f9ea5c38e2
---
 .../credentials/DefaultCombinedPicker.java    | 43 +++++++++++++++----
 1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/src/com/android/settings/applications/credentials/DefaultCombinedPicker.java b/src/com/android/settings/applications/credentials/DefaultCombinedPicker.java
index dcf8fa8244e..a813ce4f5dd 100644
--- a/src/com/android/settings/applications/credentials/DefaultCombinedPicker.java
+++ b/src/com/android/settings/applications/credentials/DefaultCombinedPicker.java
@@ -28,6 +28,8 @@ import android.credentials.CredentialProviderInfo;
 import android.credentials.SetEnabledProvidersException;
 import android.net.Uri;
 import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
 import android.os.OutcomeReceiver;
 import android.os.UserHandle;
 import android.provider.Settings;
@@ -43,7 +45,6 @@ import com.android.internal.content.PackageMonitor;
 import com.android.settings.R;
 import com.android.settings.applications.defaultapps.DefaultAppPickerFragment;
 import com.android.settingslib.applications.DefaultAppInfo;
-import com.android.settingslib.utils.ThreadUtils;
 import com.android.settingslib.widget.CandidateInfo;
 
 import java.util.ArrayList;
@@ -65,6 +66,8 @@ public class DefaultCombinedPicker extends DefaultAppPickerFragment {
     private CredentialManager mCredentialManager;
     private int mIntentSenderUserId = -1;
 
+    private static final Handler sMainHandler = new Handler(Looper.getMainLooper());
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -132,17 +135,44 @@ public class DefaultCombinedPicker extends DefaultAppPickerFragment {
             new PackageMonitor() {
                 @Override
                 public void onPackageAdded(String packageName, int uid) {
-                    ThreadUtils.postOnMainThread(() -> update());
+                    sMainHandler.post(
+                            () -> {
+                                // See b/296164461 for context
+                                if (getContext() == null) {
+                                    Log.w(TAG, "context is null");
+                                    return;
+                                }
+
+                                update();
+                            });
                 }
 
                 @Override
                 public void onPackageModified(String packageName) {
-                    ThreadUtils.postOnMainThread(() -> update());
+                    sMainHandler.post(
+                            () -> {
+                                // See b/296164461 for context
+                                if (getContext() == null) {
+                                    Log.w(TAG, "context is null");
+                                    return;
+                                }
+
+                                update();
+                            });
                 }
 
                 @Override
                 public void onPackageRemoved(String packageName, int uid) {
-                    ThreadUtils.postOnMainThread(() -> update());
+                    sMainHandler.post(
+                            () -> {
+                                // See b/296164461 for context
+                                if (getContext() == null) {
+                                    Log.w(TAG, "context is null");
+                                    return;
+                                }
+
+                                update();
+                            });
                 }
             };
 
@@ -275,10 +305,7 @@ public class DefaultCombinedPicker extends DefaultAppPickerFragment {
     protected CharSequence getConfirmationMessage(CandidateInfo appInfo) {
         // If we are selecting none then show a warning label.
         if (appInfo == null) {
-            final String message =
-                    getContext()
-                            .getString(
-                                    R.string.credman_confirmation_message);
+            final String message = getContext().getString(R.string.credman_confirmation_message);
             return Html.fromHtml(message);
         }
         final CharSequence appName = appInfo.loadLabel();