Get the ringtone name in background thread.

- to prevent anr, retrieve the current ringtone in background thread.

Change-Id: I701adfa618553c03aa24719b2550ea3ee97d9bfa
Fixes: 117124470
Test: make RunSettingsRoboTests

src/com/android/settings/notification/RingtonePreferenceControllerBase.java

@@ -25,6 +25,7 @@ import androidx.preference.Preference;
 
 import com.android.settings.core.PreferenceControllerMixin;
 import com.android.settingslib.core.AbstractPreferenceController;
+import com.android.settingslib.utils.ThreadUtils;
 
 public abstract class RingtonePreferenceControllerBase extends AbstractPreferenceController
         implements PreferenceControllerMixin {
@@ -45,11 +46,17 @@ public abstract class RingtonePreferenceControllerBase extends AbstractPreferenc
 
     @Override
     public void updateState(Preference preference) {
+        ThreadUtils.postOnBackgroundThread(() -> updateSummary(preference));
+    }
+
+    private void updateSummary(Preference preference) {
         Uri ringtoneUri = RingtoneManager.getActualDefaultRingtoneUri(mContext, getRingtoneType());
         final CharSequence summary = Ringtone.getTitle(
             mContext, ringtoneUri, false /* followSettingsUri */, true /* allowRemote */);
         if (summary != null) {
-            preference.setSummary(summary);
+            ThreadUtils.postOnMainThread(() -> {
+                preference.setSummary(summary);
+            });
         }
     }