[Settings] init UI entry for Cross SIM calling

Create an empty UI entry for Cross SIM calling.

TODO: fill-in implementation based on UI within document.

Document:
https://docs.google.com/document/d/1INEwrq5_M62hJcRMshdO0OaFruVR0goYByxdpMdFr_o/edit?disco=AAAAHQo7ang&ts=5fadc9b4&usp_dm=true#heading=h.8gw4a7e503pz

Bug: 174012397
Test: manual
Change-Id: I344a18954924c4665295ef244bfee773f3f98d55

res/values/strings.xml

@@ -12258,6 +12258,15 @@
     <!-- Summary for Wi-Fi calling to explain this feature [CHAR LIMIT=NONE] -->
     <string name="wifi_calling_summary">Use Wi\u2011Fi for calls to improve quality</string>
 
+    <!-- Mobile network settings screen, title of Cross SIM calling setting.  [CHAR LIMIT=NONE] -->
+    <string name="cross_sim_calling_settings_title">Cross SIM calling</string>
+
+    <!-- Cross SIM calling summary.  [CHAR LIMIT=100] -->
+    <string name="cross_sim_calling_setting_summary">Allow another SIM calls and SMSs over this SIM.</string>
+
+    <!-- List of synonyms for the cross SIM calling titles, used to match in settings search [CHAR LIMIT=NONE] -->
+    <string name="keywords_cross_sim_calling">cross sim calling</string>
+
     <!-- Title for enable MMS notification when trying to receive MMS.  [CHAR LIMIT=40] -->
     <string name="enable_receiving_mms_notification_title">Incoming MMS message</string>
     <!-- Title for enable MMS notification when trying to send MMS.  [CHAR LIMIT=40] -->

res/xml/mobile_network_settings.xml

@@ -173,6 +173,14 @@
                 android:persistent="true"
                 settings:controller="com.android.settings.network.telephony.VideoCallingPreferenceController"/>
 
+            <SwitchPreference
+                android:key="cross_sim_calling_key"
+                android:title="@string/cross_sim_calling_settings_title"
+                android:persistent="false"
+                android:summary="@string/cross_sim_calling_setting_summary"
+                settings:keywords="@string/keywords_cross_sim_calling"
+                settings:controller="com.android.settings.network.telephony.CrossSimCallingPreferenceController"/>
+
         </PreferenceCategory>
 
         <com.android.settings.network.telephony.cdma.CdmaListPreference

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

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2020 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;
+
+/**
+ * Preference controller for "Cross SIM Calling"
+ **/
+public class CrossSimCallingPreferenceController extends TelephonyTogglePreferenceController {
+
+    /**
+     * Class constructor of cross sim calling.
+     *
+     * @param context of settings
+     * @param key assigned within UI entry of XML file
+     **/
+    public CrossSimCallingPreferenceController(Context context, String key) {
+        super(context, key);
+    }
+
+    /**
+     * Initialization based on given subscription id.
+     *
+     * @param subId is the subscription id
+     * @return this instance after initialization
+     **/
+    public CrossSimCallingPreferenceController init(int subId) {
+        return this;
+    }
+
+    @Override
+    public int getAvailabilityStatus(int subId) {
+        return CONDITIONALLY_UNAVAILABLE;
+    }
+
+    /**
+     * Implementation of abstract methods
+     **/
+    public boolean setChecked(boolean isChecked) {
+        return false;
+    }
+
+    /**
+     * Implementation of abstract methods
+     **/
+    public boolean isChecked() {
+        return false;
+    }
+
+}

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

@@ -173,8 +173,11 @@ public class MobileNetworkSettings extends AbstractMobileNetworkSettings {
 
         final VideoCallingPreferenceController videoCallingPreferenceController =
                 use(VideoCallingPreferenceController.class).init(mSubId);
+        final CrossSimCallingPreferenceController crossSimCallingPreferenceController =
+                use(CrossSimCallingPreferenceController.class).init(mSubId);
         use(CallingPreferenceCategoryController.class).setChildren(
-                Arrays.asList(wifiCallingPreferenceController, videoCallingPreferenceController));
+                Arrays.asList(wifiCallingPreferenceController, videoCallingPreferenceController,
+                        crossSimCallingPreferenceController));
         use(Enhanced4gLtePreferenceController.class).init(mSubId)
                 .addListener(videoCallingPreferenceController);
         use(Enhanced4gCallingPreferenceController.class).init(mSubId)

tests/unit/src/com/android/settings/network/telephony/CrossSimCallingPreferenceControllerTest.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2020 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 org.mockito.Mockito.spy;
+
+import android.content.Context;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class CrossSimCallingPreferenceControllerTest {
+    private static final int SUB_ID = 2;
+
+    private CrossSimCallingPreferenceController mController;
+    private Context mContext;
+
+    @Before
+    public void setUp() {
+        mContext = spy(ApplicationProvider.getApplicationContext());
+
+        mController = new CrossSimCallingPreferenceController(mContext, "cross_sim_calling_key");
+        mController.init(SUB_ID);
+    }
+}