From ff484e11e9b6bce5b184e29b55e3f61b39b504d1 Mon Sep 17 00:00:00 2001
From: Antony Sargent <asargent@google.com>
Date: Tue, 22 Jan 2019 10:57:25 -0800
Subject: [PATCH] Add default calls/SMS subscription prefs to mobile details
 page

This adds prefs to the the details page for mobile network subscriptions
that appear in multi-SIM mode. They show which subscription is set as
the default for calls and SMS respectively, and let the user change what
the default is for each. They can be set to either a specific
subscription, or set to "Ask every time".

Bug: 122670283
Test: make RunSettingsRoboTests
Change-Id: Id2b23e4b5c3d1b5c04b5766e73fc8202c05d8f75
---
 res/values/strings.xml                        |  11 +
 res/xml/mobile_network_settings_v2.xml        |  21 +-
 .../settings/network/SubscriptionUtil.java    |   2 +-
 .../CallsDefaultSubscriptionController.java   |  43 +++
 .../DefaultSubscriptionController.java        | 175 +++++++++++
 .../telephony/MobileNetworkSettings.java      |   4 +
 .../SmsDefaultSubscriptionController.java     |  43 +++
 .../DefaultSubscriptionControllerTest.java    | 289 ++++++++++++++++++
 .../telephony/MobileNetworkSettingsTest.java  |   8 +-
 9 files changed, 590 insertions(+), 6 deletions(-)
 create mode 100644 src/com/android/settings/network/telephony/CallsDefaultSubscriptionController.java
 create mode 100644 src/com/android/settings/network/telephony/DefaultSubscriptionController.java
 create mode 100644 src/com/android/settings/network/telephony/SmsDefaultSubscriptionController.java
 create mode 100644 tests/robotests/src/com/android/settings/network/telephony/DefaultSubscriptionControllerTest.java

diff --git a/res/values/strings.xml b/res/values/strings.xml
index a0820743f7f..5a437cf95c8 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -10360,6 +10360,17 @@
     <string name="mobile_data_settings_title">Mobile data</string>
     <!-- Mobile network settings screen, title of Mobile data switch preference [CHAR LIMIT=NONE] -->
     <string name="mobile_data_settings_summary">Access data using mobile network</string>
+    <!-- Mobile network settings screen, title of item showing the name of the default subscription
+     that will be used for calls. This only appears in multi-SIM mode. [CHAR LIMIT=NONE] -->
+    <string name="calls_preference">Calls preference</string>
+    <!-- Mobile network settings screen, title of item showing the name of the default subscription
+     that will be used for SMS messages. This only appears in multi-SIM mode. [CHAR LIMIT=NONE] -->
+    <string name="sms_preference">SMS preference</string>
+    <!-- Mobile network settings screen, a label in a chooser dialog that appears when choosing the
+    default subscription to use for either calls or SMS when in multi-SIM mode. This label means
+    that the user will be asked which mobile network subscription to use every time they place a
+    call or send an SMS, instead of defaulting to one particular subscription. [CHAR LIMIT=40]-->
+    <string name="calls_and_sms_ask_every_time">Ask every time</string>
 
     <!-- Summary of the 'Mobile network' item on the Network & internet page when there is no mobile
          service setup yet (eg no SIM card inserted and no eSIM configured). Tapping it leads to a
diff --git a/res/xml/mobile_network_settings_v2.xml b/res/xml/mobile_network_settings_v2.xml
index 7a19c325334..6273ad91e42 100644
--- a/res/xml/mobile_network_settings_v2.xml
+++ b/res/xml/mobile_network_settings_v2.xml
@@ -17,24 +17,37 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:settings="http://schemas.android.com/apk/res-auto"
     android:key="mobile_network_pref_screen"
-    settings:initialExpandedChildrenCount="5">
+    settings:initialExpandedChildrenCount="7">
 
     <com.android.settings.datausage.DataUsageSummaryPreference
         android:key="status_header"
         android:visibility="gone"
         android:selectable="false" />
 
+    <ListPreference
+        android:key="calls_preference"
+        android:title="@string/calls_preference"
+        settings:controller="com.android.settings.network.telephony.CallsDefaultSubscriptionController"
+        settings:allowDividerAbove="true" />
+
+    <ListPreference
+        android:key="sms_preference"
+        android:title="@string/sms_preference"
+        settings:controller="com.android.settings.network.telephony.SmsDefaultSubscriptionController" />
+
     <Preference
         android:key="cdma_lte_data_service_key"
         android:title="@string/cdma_lte_data_service"
-        settings:controller="com.android.settings.network.telephony.DataServiceSetupPreferenceController">
-    </Preference>
+        settings:controller="com.android.settings.network.telephony.DataServiceSetupPreferenceController"
+        settings:allowDividerAbove="true"
+        settings:allowDividerBelow="false" />
 
     <SwitchPreference
         android:key="mobile_data_enable"
         android:title="@string/mobile_data_settings_title"
         android:summary="@string/mobile_data_settings_summary"
-        settings:controller="com.android.settings.network.telephony.MobileDataPreferenceController"/>
+        settings:controller="com.android.settings.network.telephony.MobileDataPreferenceController"
+        settings:allowDividerAbove="true"/>
 
     <com.android.settingslib.RestrictedSwitchPreference
         android:key="button_roaming_key"
diff --git a/src/com/android/settings/network/SubscriptionUtil.java b/src/com/android/settings/network/SubscriptionUtil.java
index fbc6eddfe75..237e08a777e 100644
--- a/src/com/android/settings/network/SubscriptionUtil.java
+++ b/src/com/android/settings/network/SubscriptionUtil.java
@@ -30,7 +30,7 @@ public class SubscriptionUtil {
     private static List<SubscriptionInfo> sResultsForTesting;
 
     @VisibleForTesting
-    static void setAvailableSubscriptionsForTesting(List<SubscriptionInfo> results) {
+    public static void setAvailableSubscriptionsForTesting(List<SubscriptionInfo> results) {
         sResultsForTesting = results;
     }
 
diff --git a/src/com/android/settings/network/telephony/CallsDefaultSubscriptionController.java b/src/com/android/settings/network/telephony/CallsDefaultSubscriptionController.java
new file mode 100644
index 00000000000..008a3e4929d
--- /dev/null
+++ b/src/com/android/settings/network/telephony/CallsDefaultSubscriptionController.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.network.telephony;
+
+import android.content.Context;
+import android.telephony.SubscriptionInfo;
+import android.telephony.SubscriptionManager;
+
+public class CallsDefaultSubscriptionController extends DefaultSubscriptionController {
+
+    public CallsDefaultSubscriptionController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    protected SubscriptionInfo getDefaultSubscriptionInfo() {
+        return mManager.getDefaultVoiceSubscriptionInfo();
+    }
+
+    @Override
+    protected int getDefaultSubscriptionId() {
+        return SubscriptionManager.getDefaultVoiceSubscriptionId();
+    }
+
+    @Override
+    protected void setDefaultSubscription(int subscriptionId) {
+        mManager.setDefaultVoiceSubId(subscriptionId);
+    }
+}
diff --git a/src/com/android/settings/network/telephony/DefaultSubscriptionController.java b/src/com/android/settings/network/telephony/DefaultSubscriptionController.java
new file mode 100644
index 00000000000..bca6750ca7b
--- /dev/null
+++ b/src/com/android/settings/network/telephony/DefaultSubscriptionController.java
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.network.telephony;
+
+import static androidx.lifecycle.Lifecycle.Event.ON_PAUSE;
+import static androidx.lifecycle.Lifecycle.Event.ON_RESUME;
+
+import android.content.Context;
+import android.telephony.SubscriptionInfo;
+import android.telephony.SubscriptionManager;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+import com.android.settings.network.SubscriptionUtil;
+import com.android.settings.network.SubscriptionsChangeListener;
+
+import java.util.List;
+
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.OnLifecycleEvent;
+import androidx.preference.ListPreference;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceScreen;
+
+/**
+ * This implements common controller functionality for a Preference letting the user see/change
+ * what mobile network subscription is used by default for some service controlled by the
+ * SubscriptionManager. This can be used for services such as Calls or SMS.
+ */
+public abstract class DefaultSubscriptionController extends BasePreferenceController implements
+        LifecycleObserver, Preference.OnPreferenceChangeListener,
+        SubscriptionsChangeListener.SubscriptionsChangeListenerClient {
+    private static final String TAG = "DefaultSubController";
+
+    protected SubscriptionsChangeListener mChangeListener;
+    protected ListPreference mPreference;
+    protected SubscriptionManager mManager;
+
+    public DefaultSubscriptionController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+        mManager = context.getSystemService(SubscriptionManager.class);
+        mChangeListener = new SubscriptionsChangeListener(context, this);
+    }
+
+    public void init(Lifecycle lifecycle) {
+        lifecycle.addObserver(this);
+    }
+
+    /** @return SubscriptionInfo for the default subscription for the service, or null if there
+     * isn't one. */
+    protected abstract SubscriptionInfo getDefaultSubscriptionInfo();
+
+    /** @return the id of the default subscription for the service, or
+     * SubscriptionManager.INVALID_SUBSCRIPTION_ID if there isn't one. */
+    protected abstract int getDefaultSubscriptionId();
+
+    /** Called to change the default subscription for the service. */
+    protected abstract void setDefaultSubscription(int subscriptionId);
+
+    @Override
+    public int getAvailabilityStatus() {
+        final List<SubscriptionInfo> subs = SubscriptionUtil.getAvailableSubscriptions(mManager);
+        if (subs.size() > 1) {
+            return AVAILABLE;
+        } else {
+            return CONDITIONALLY_UNAVAILABLE;
+        }
+    }
+
+    @OnLifecycleEvent(ON_RESUME)
+    public void onResume() {
+        mChangeListener.start();
+        updateEntries();
+    }
+
+    @OnLifecycleEvent(ON_PAUSE)
+    public void onPause() {
+        mChangeListener.stop();
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = screen.findPreference(getPreferenceKey());
+        updateEntries();
+    }
+
+    @Override
+    public CharSequence getSummary() {
+        final SubscriptionInfo info = getDefaultSubscriptionInfo();
+        if (info != null) {
+            return info.getDisplayName();
+        } else {
+            return mContext.getString(R.string.calls_and_sms_ask_every_time);
+        }
+    }
+
+    private void updateEntries() {
+        if (mPreference == null) {
+            return;
+        }
+        if (!isAvailable()) {
+            mPreference.setVisible(false);
+            return;
+        }
+        mPreference.setVisible(true);
+
+        final List<SubscriptionInfo> subs = SubscriptionUtil.getAvailableSubscriptions(mManager);
+
+        // We'll have one entry for each available subscription, plus one for a "ask me every
+        // time" entry at the end.
+        final CharSequence[] displayNames = new CharSequence[subs.size() + 1];
+        final CharSequence[] subscriptionIds = new CharSequence[subs.size() + 1];
+
+        final int serviceDefaultSubId = getDefaultSubscriptionId();
+        boolean subIsAvailable = false;
+
+        int i = 0;
+        for (; i < subs.size(); i++) {
+            displayNames[i] = subs.get(i).getDisplayName();
+            final int subId = subs.get(i).getSubscriptionId();
+            subscriptionIds[i] = Integer.toString(subId);
+            if (subId == serviceDefaultSubId) {
+                subIsAvailable = true;
+            }
+        }
+        // Add the extra "Ask every time" value at the end.
+        displayNames[i] = mContext.getString(R.string.calls_and_sms_ask_every_time);
+        subscriptionIds[i] = Integer.toString(SubscriptionManager.INVALID_SUBSCRIPTION_ID);
+
+        mPreference.setEntries(displayNames);
+        mPreference.setEntryValues(subscriptionIds);
+
+        if (subIsAvailable) {
+            mPreference.setValue(Integer.toString(serviceDefaultSubId));
+        } else {
+            mPreference.setValue(Integer.toString(SubscriptionManager.INVALID_SUBSCRIPTION_ID));
+        }
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        final int subscriptionId = Integer.parseInt((String) newValue);
+        setDefaultSubscription(subscriptionId);
+        refreshSummary(mPreference);
+        return true;
+    }
+
+    @Override
+    public void onAirplaneModeChanged(boolean airplaneModeEnabled) {
+    }
+
+    @Override
+    public void onSubscriptionsChanged() {
+        if (mPreference != null) {
+            updateEntries();
+            refreshSummary(mPreference);
+        }
+    }
+}
diff --git a/src/com/android/settings/network/telephony/MobileNetworkSettings.java b/src/com/android/settings/network/telephony/MobileNetworkSettings.java
index 9665c093da5..52015868cf8 100644
--- a/src/com/android/settings/network/telephony/MobileNetworkSettings.java
+++ b/src/com/android/settings/network/telephony/MobileNetworkSettings.java
@@ -126,6 +126,10 @@ public class MobileNetworkSettings extends RestrictedDashboardFragment {
     public void onAttach(Context context) {
         super.onAttach(context);
 
+        if (FeatureFlagPersistent.isEnabled(getContext(), FeatureFlags.NETWORK_INTERNET_V2)) {
+          use(CallsDefaultSubscriptionController.class).init(getLifecycle());
+          use(SmsDefaultSubscriptionController.class).init(getLifecycle());
+        }
         use(MobileDataPreferenceController.class).init(getFragmentManager(), mSubId);
         use(RoamingPreferenceController.class).init(getFragmentManager(), mSubId);
         use(ApnPreferenceController.class).init(mSubId);
diff --git a/src/com/android/settings/network/telephony/SmsDefaultSubscriptionController.java b/src/com/android/settings/network/telephony/SmsDefaultSubscriptionController.java
new file mode 100644
index 00000000000..b9992199ff7
--- /dev/null
+++ b/src/com/android/settings/network/telephony/SmsDefaultSubscriptionController.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.network.telephony;
+
+import android.content.Context;
+import android.telephony.SubscriptionInfo;
+import android.telephony.SubscriptionManager;
+
+public class SmsDefaultSubscriptionController extends DefaultSubscriptionController {
+
+    public SmsDefaultSubscriptionController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    protected SubscriptionInfo getDefaultSubscriptionInfo() {
+        return mManager.getDefaultSmsSubscriptionInfo();
+    }
+
+    @Override
+    protected int getDefaultSubscriptionId() {
+        return SubscriptionManager.getDefaultSmsSubscriptionId();
+    }
+
+    @Override
+    protected void setDefaultSubscription(int subscriptionId) {
+        mManager.setDefaultSmsSubId(subscriptionId);
+    }
+}
diff --git a/tests/robotests/src/com/android/settings/network/telephony/DefaultSubscriptionControllerTest.java b/tests/robotests/src/com/android/settings/network/telephony/DefaultSubscriptionControllerTest.java
new file mode 100644
index 00000000000..f7a2567dbf1
--- /dev/null
+++ b/tests/robotests/src/com/android/settings/network/telephony/DefaultSubscriptionControllerTest.java
@@ -0,0 +1,289 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.network.telephony;
+
+import static com.android.settings.core.BasePreferenceController.AVAILABLE;
+import static com.android.settings.core.BasePreferenceController.CONDITIONALLY_UNAVAILABLE;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.telephony.SubscriptionInfo;
+import android.telephony.SubscriptionManager;
+
+import com.android.settings.R;
+import com.android.settings.network.SubscriptionUtil;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+import java.util.Arrays;
+
+import androidx.preference.ListPreference;
+import androidx.preference.PreferenceScreen;
+
+@RunWith(RobolectricTestRunner.class)
+public class DefaultSubscriptionControllerTest {
+    @Mock
+    private SubscriptionManager mManager;
+    @Mock
+    private PreferenceScreen mScreen;
+
+    private ListPreference mListPreference;
+    private Context mContext;
+    private DefaultSubscriptionController mController;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mContext = spy(RuntimeEnvironment.application);
+        when(mContext.getSystemService(SubscriptionManager.class)).thenReturn(mManager);
+        final String key = "prefkey";
+        mController = spy(new TestDefaultSubscriptionController(mContext, key));
+        mListPreference = spy(new ListPreference(mContext));
+        when(mScreen.findPreference(key)).thenReturn(mListPreference);
+    }
+
+    @After
+    public void tearDown() {
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(null);
+    }
+
+    @Test
+    public void getAvailabilityStatus_onlyOneSubscription_notAvailable() {
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(
+                createMockSub(1, "sub1")));
+        assertThat(mController.getAvailabilityStatus()).isEqualTo(CONDITIONALLY_UNAVAILABLE);
+    }
+
+    @Test
+    public void getAvailabilityStatus_twoSubscriptions_isAvailable() {
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(
+                createMockSub(1, "sub1"),
+                createMockSub(2, "sub2")));
+        assertThat(mController.getAvailabilityStatus()).isEqualTo(AVAILABLE);
+    }
+
+    @Test
+    public void displayPreference_twoSubscriptionsSub1Default_correctListPreferenceValues() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        doReturn(sub1.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+
+        final CharSequence entry = mListPreference.getEntry();
+        final String value = mListPreference.getValue();
+        assertThat(entry).isEqualTo("sub1");
+        assertThat(value).isEqualTo("111");
+
+        final CharSequence[] entries = mListPreference.getEntries();
+        assertThat(entries.length).isEqualTo(3);
+        assertThat(entries[0]).isEqualTo("sub1");
+        assertThat(entries[1]).isEqualTo("sub2");
+        assertThat(entries[2]).isEqualTo(mContext.getString(R.string.calls_and_sms_ask_every_time));
+
+        final CharSequence[] entryValues = mListPreference.getEntryValues();
+        assertThat(entryValues.length).isEqualTo(3);
+        assertThat(entryValues[0]).isEqualTo("111");
+        assertThat(entryValues[1]).isEqualTo("222");
+        assertThat(entryValues[2]).isEqualTo(
+                Integer.toString(SubscriptionManager.INVALID_SUBSCRIPTION_ID));
+    }
+
+    @Test
+    public void displayPreference_twoSubscriptionsSub2Default_correctListPreferenceValues() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        doReturn(sub2.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+
+        final CharSequence entry = mListPreference.getEntry();
+        final String value = mListPreference.getValue();
+        assertThat(entry).isEqualTo("sub2");
+        assertThat(value).isEqualTo("222");
+
+        final CharSequence[] entries = mListPreference.getEntries();
+        assertThat(entries.length).isEqualTo(3);
+        assertThat(entries[0]).isEqualTo("sub1");
+        assertThat(entries[1]).isEqualTo("sub2");
+        assertThat(entries[2]).isEqualTo(mContext.getString(R.string.calls_and_sms_ask_every_time));
+
+        final CharSequence[] entryValues = mListPreference.getEntryValues();
+        assertThat(entryValues.length).isEqualTo(3);
+        assertThat(entryValues[0]).isEqualTo("111");
+        assertThat(entryValues[1]).isEqualTo("222");
+        assertThat(entryValues[2]).isEqualTo(
+                Integer.toString(SubscriptionManager.INVALID_SUBSCRIPTION_ID));
+    }
+
+    @Test
+    public void onPreferenceChange_prefChangedToSub2_callbackCalledCorrectly() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        doReturn(sub1.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+        mListPreference.setValue("222");
+        mController.onPreferenceChange(mListPreference, "222");
+        verify(mController).setDefaultSubscription(eq(222));
+    }
+
+    @Test
+    public void onPreferenceChange_prefChangedToAlwaysAsk_callbackCalledCorrectly() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        doReturn(sub1.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+        mListPreference.setValue(Integer.toString(SubscriptionManager.INVALID_SUBSCRIPTION_ID));
+        mController.onPreferenceChange(mListPreference,
+                Integer.toString(SubscriptionManager.INVALID_SUBSCRIPTION_ID));
+        verify(mController).setDefaultSubscription(
+                eq(SubscriptionManager.INVALID_SUBSCRIPTION_ID));
+    }
+
+    @Test
+    public void onSubscriptionsChanged_twoSubscriptionsDefaultChanges_selectedEntryGetsUpdated() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        doReturn(sub1.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+        assertThat( mListPreference.getEntry()).isEqualTo("sub1");
+        assertThat(mListPreference.getValue()).isEqualTo("111");
+
+        doReturn(sub2.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+        mController.onSubscriptionsChanged();
+        assertThat( mListPreference.getEntry()).isEqualTo("sub2");
+        assertThat(mListPreference.getValue()).isEqualTo("222");
+    }
+
+    @Test
+    public void onSubscriptionsChanged_goFromTwoSubscriptionsToOne_prefDisappears() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        doReturn(sub1.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+        assertThat(mController.isAvailable()).isTrue();
+        assertThat(mListPreference.isVisible()).isTrue();
+
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1));
+        mController.onSubscriptionsChanged();
+
+        assertThat(mController.isAvailable()).isFalse();
+        assertThat(mListPreference.isVisible()).isFalse();
+    }
+
+    @Test
+    public void onSubscriptionsChanged_goFromOneSubscriptionToTwo_prefAppears() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1));
+        doReturn(sub1.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+        assertThat(mController.isAvailable()).isFalse();
+        assertThat(mListPreference.isVisible()).isFalse();
+
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        mController.onSubscriptionsChanged();
+
+        assertThat(mController.isAvailable()).isTrue();
+        assertThat(mListPreference.isVisible()).isTrue();
+    }
+
+    @Test
+    public void onSubscriptionsChanged_goFromTwoToThreeSubscriptions_listGetsUpdated() {
+        final SubscriptionInfo sub1 = createMockSub(111, "sub1");
+        final SubscriptionInfo sub2 = createMockSub(222, "sub2");
+        final SubscriptionInfo sub3 = createMockSub(333, "sub3");
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2));
+        doReturn(sub1.getSubscriptionId()).when(mController).getDefaultSubscriptionId();
+
+        mController.displayPreference(mScreen);
+        assertThat(mListPreference.getEntries().length).isEqualTo(3);
+
+        SubscriptionUtil.setAvailableSubscriptionsForTesting(Arrays.asList(sub1, sub2, sub3));
+        mController.onSubscriptionsChanged();
+
+        assertThat(mController.isAvailable()).isTrue();
+        assertThat(mListPreference.isVisible()).isTrue();
+        final CharSequence[] entries = mListPreference.getEntries();
+        final CharSequence[] entryValues = mListPreference.getEntryValues();
+        assertThat(entries.length).isEqualTo(4);
+        assertThat(entries[0].toString()).isEqualTo("sub1");
+        assertThat(entries[1].toString()).isEqualTo("sub2");
+        assertThat(entries[2].toString()).isEqualTo("sub3");
+        assertThat(entries[3].toString()).isEqualTo(
+                mContext.getString(R.string.calls_and_sms_ask_every_time));
+        assertThat(entryValues[0].toString()).isEqualTo("111");
+        assertThat(entryValues[1].toString()).isEqualTo("222");
+        assertThat(entryValues[2].toString()).isEqualTo("333");
+        assertThat(entryValues[3].toString()).isEqualTo(
+                Integer.toString(SubscriptionManager.INVALID_SUBSCRIPTION_ID));
+    }
+
+    private SubscriptionInfo createMockSub(int id, String displayName) {
+        final SubscriptionInfo sub = mock(SubscriptionInfo.class);
+        when(sub.getSubscriptionId()).thenReturn(id);
+        when(sub.getDisplayName()).thenReturn(displayName);
+        return sub;
+    }
+
+    private class TestDefaultSubscriptionController extends DefaultSubscriptionController {
+
+        public TestDefaultSubscriptionController(Context context, String preferenceKey) {
+            super(context, preferenceKey);
+        }
+
+        @Override
+        protected SubscriptionInfo getDefaultSubscriptionInfo() {
+            return null;
+        }
+
+        @Override
+        protected int getDefaultSubscriptionId() {
+            return 0;
+        }
+
+        @Override
+        protected void setDefaultSubscription(int subscriptionId) {
+        }
+    }
+}
diff --git a/tests/robotests/src/com/android/settings/network/telephony/MobileNetworkSettingsTest.java b/tests/robotests/src/com/android/settings/network/telephony/MobileNetworkSettingsTest.java
index 0240bd834f8..55a4224bcbb 100644
--- a/tests/robotests/src/com/android/settings/network/telephony/MobileNetworkSettingsTest.java
+++ b/tests/robotests/src/com/android/settings/network/telephony/MobileNetworkSettingsTest.java
@@ -85,7 +85,13 @@ public class MobileNetworkSettingsTest {
     }
 
     @Test
-    public void onAttach_noCrash() {
+    public void onAttach_noV2Flag_noCrash() {
+        mFragment.onAttach(mContext);
+    }
+
+    @Test
+    public void onAttach_v2Flag_noCrash() {
+        FeatureFlagPersistent.setEnabled(mContext, FeatureFlags.NETWORK_INTERNET_V2, true);
         mFragment.onAttach(mContext);
     }