Prevent extra reloads in mobile networking page/controllers

On the mobile network details page, as well as in several preference
controllers used in various page, we had listeners for the
ACTION_RADIO_TECHNOLOGY_CHANGED broadcast that when fired would cause a
reload. It turns out that this gets broadcast as a sticky intent, so our
callbaks would fire just after registering to listen, resulting in lots
of unnecessary extra reloading. This was particularly noticable on the
mobile network details page because the entire page gets reloaded.

The fix is to make our listeners ignore the broadcast if it's the
initial sticky one.

Bug: 126419558
Test: make RunSettingsRoboTests
Change-Id: I6ab7b43d74b07a839e45ce5368e45809be658b9d

src/com/android/settings/network/SubscriptionsChangeListener.java

@@ -59,7 +59,9 @@ public class SubscriptionsChangeListener extends ContentObserver {
         mBroadcastReceiver = new BroadcastReceiver() {
             @Override
             public void onReceive(Context context, Intent intent) {
-                subscriptionsChangedCallback();
+                if (!isInitialStickyBroadcast()) {
+                    subscriptionsChangedCallback();
+                }
             }
         };
     }

src/com/android/settings/network/telephony/MobileNetworkActivity.java

@@ -85,7 +85,14 @@ public class MobileNetworkActivity extends SettingsBaseActivity {
             setContentView(R.layout.mobile_network_settings_container);
         }
         setActionBar(findViewById(R.id.mobile_action_bar));
-        mPhoneChangeReceiver = new PhoneChangeReceiver();
+        mPhoneChangeReceiver = new PhoneChangeReceiver(this, () -> {
+            if (mCurSubscriptionId != SUB_ID_NULL) {
+                // When the radio changes (ex: CDMA->GSM), refresh the fragment.
+                // This is very rare.
+                switchFragment(new MobileNetworkSettings(), mCurSubscriptionId,
+                        true /* forceUpdate */);
+            }
+        });
         mSubscriptionManager = getSystemService(SubscriptionManager.class);
         mSubscriptionInfos = mSubscriptionManager.getActiveSubscriptionInfoList(true);
         mCurSubscriptionId = savedInstanceState != null
@@ -103,16 +110,14 @@ public class MobileNetworkActivity extends SettingsBaseActivity {
     @Override
     protected void onStart() {
         super.onStart();
-        final IntentFilter intentFilter = new IntentFilter(
-                TelephonyIntents.ACTION_RADIO_TECHNOLOGY_CHANGED);
-        registerReceiver(mPhoneChangeReceiver, intentFilter);
+        mPhoneChangeReceiver.register();
         mSubscriptionManager.addOnSubscriptionsChangedListener(mOnSubscriptionsChangeListener);
     }
 
     @Override
     protected void onStop() {
         super.onStop();
-        unregisterReceiver(mPhoneChangeReceiver);
+        mPhoneChangeReceiver.unregister();
         mSubscriptionManager.removeOnSubscriptionsChangedListener(mOnSubscriptionsChangeListener);
     }
 
@@ -235,14 +240,35 @@ public class MobileNetworkActivity extends SettingsBaseActivity {
         return MOBILE_SETTINGS_TAG + subscriptionId;
     }
 
-    private class PhoneChangeReceiver extends BroadcastReceiver {
+    @VisibleForTesting
+    static class PhoneChangeReceiver extends BroadcastReceiver {
+        private static final IntentFilter RADIO_TECHNOLOGY_CHANGED_FILTER = new IntentFilter(
+                TelephonyIntents.ACTION_RADIO_TECHNOLOGY_CHANGED);
+
+        private Context mContext;
+        private Client mClient;
+
+        interface Client {
+            void onPhoneChange();
+        }
+
+        public PhoneChangeReceiver(Context context, Client client) {
+            mContext = context;
+            mClient = client;
+        }
+
+        public void register() {
+            mContext.registerReceiver(this, RADIO_TECHNOLOGY_CHANGED_FILTER);
+        }
+
+        public void unregister() {
+            mContext.unregisterReceiver(this);
+        }
+
         @Override
         public void onReceive(Context context, Intent intent) {
-            // When the radio changes (ex: CDMA->GSM), refresh the fragment.
-            // This is very rare to happen.
-            if (mCurSubscriptionId != SUB_ID_NULL) {
-                switchFragment(new MobileNetworkSettings(), mCurSubscriptionId,
-                        true /* forceUpdate */);
+            if (!isInitialStickyBroadcast()) {
+                mClient.onPhoneChange();
             }
         }
     }