[Settings] Avoid crash for VoIP account displayed as default voice

When displaying VoIP account in Default voice account UI within
mobile network configuration, some null pointer checking need to
applied due to this is no longer a real account bind to SIM card.

Bug: 157334667
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=DefaultSubscriptionControllerTest
Change-Id: I3927362676c867ac245f16e1d00ea953b21ec1d4

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

@@ -34,6 +34,7 @@ import androidx.preference.ListPreference;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceScreen;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.settings.R;
 import com.android.settings.network.SubscriptionUtil;
 import com.android.settings.network.SubscriptionsChangeListener;
@@ -64,7 +65,6 @@ public abstract class DefaultSubscriptionController extends TelephonyBasePrefere
     public DefaultSubscriptionController(Context context, String preferenceKey) {
         super(context, preferenceKey);
         mManager = context.getSystemService(SubscriptionManager.class);
-        mTelecomManager = mContext.getSystemService(TelecomManager.class);
         mChangeListener = new SubscriptionsChangeListener(context, this);
     }
 
@@ -184,12 +184,12 @@ public abstract class DefaultSubscriptionController extends TelephonyBasePrefere
      */
     public PhoneAccountHandle getDefaultCallingAccountHandle() {
         final PhoneAccountHandle currentSelectPhoneAccount =
-                mTelecomManager.getUserSelectedOutgoingPhoneAccount();
+                getTelecomManager().getUserSelectedOutgoingPhoneAccount();
         if (currentSelectPhoneAccount == null) {
             return null;
         }
         final List<PhoneAccountHandle> accountHandles =
-                mTelecomManager.getCallCapablePhoneAccounts(false);
+                getTelecomManager().getCallCapablePhoneAccounts(false);
         final PhoneAccountHandle emergencyAccountHandle = new PhoneAccountHandle(
                 PSTN_CONNECTION_SERVICE_COMPONENT, EMERGENCY_ACCOUNT_HANDLE_ID);
         if (currentSelectPhoneAccount.equals(emergencyAccountHandle)) {
@@ -203,14 +203,30 @@ public abstract class DefaultSubscriptionController extends TelephonyBasePrefere
         return null;
     }
 
+    @VisibleForTesting
+    TelecomManager getTelecomManager() {
+        if (mTelecomManager == null) {
+            mTelecomManager = mContext.getSystemService(TelecomManager.class);
+        }
+        return mTelecomManager;
+    }
+
+    @VisibleForTesting
+    PhoneAccount getPhoneAccount(PhoneAccountHandle handle) {
+        return getTelecomManager().getPhoneAccount(handle);
+    }
+
     /**
      * Check if calling account bind to subscription
      *
      * @param handle {@link PhoneAccountHandle} for specific calling account
      */
     public boolean isCallingAccountBindToSubscription(PhoneAccountHandle handle) {
-        return mTelecomManager.getPhoneAccount(handle)
+        final PhoneAccount account = getPhoneAccount(handle);
-                .hasCapabilities(PhoneAccount.CAPABILITY_SIM_SUBSCRIPTION);
+        if (account == null) {
+            return false;
+        }
+        return account.hasCapabilities(PhoneAccount.CAPABILITY_SIM_SUBSCRIPTION);
     }
 
     /**
@@ -220,7 +236,11 @@ public abstract class DefaultSubscriptionController extends TelephonyBasePrefere
      * @return label of calling account
      */
     public CharSequence getLabelFromCallingAccount(PhoneAccountHandle handle) {
-        CharSequence label = mTelecomManager.getPhoneAccount(handle).getLabel();
+        CharSequence label = null;
+        final PhoneAccount account = getPhoneAccount(handle);
+        if (account != null) {
+            label = account.getLabel();
+        }
         if (label != null) {
             label = mContext.getPackageManager().getUserBadgedLabel(label, handle.getUserHandle());
         }

tests/robotests/src/com/android/settings/network/telephony/DefaultSubscriptionControllerTest.java

@@ -21,6 +21,7 @@ import static com.android.settings.core.BasePreferenceController.CONDITIONALLY_U
 
 import static com.google.common.truth.Truth.assertThat;
 
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
@@ -32,6 +33,9 @@ import android.content.Context;
 import android.telephony.SubscriptionInfo;
 import android.telephony.SubscriptionManager;
 
+import androidx.preference.ListPreference;
+import androidx.preference.PreferenceScreen;
+
 import com.android.settings.R;
 import com.android.settings.network.SubscriptionUtil;
 
@@ -46,9 +50,6 @@ import org.robolectric.RuntimeEnvironment;
 
 import java.util.Arrays;
 
-import androidx.preference.ListPreference;
-import androidx.preference.PreferenceScreen;
-
 @RunWith(RobolectricTestRunner.class)
 public class DefaultSubscriptionControllerTest {
     @Mock
@@ -91,6 +92,20 @@ public class DefaultSubscriptionControllerTest {
         assertThat(mController.getAvailabilityStatus()).isEqualTo(AVAILABLE);
     }
 
+    @Test
+    public void isCallingAccountBindToSubscription_invalidAccount_withoutCrash() {
+        doReturn(null).when(mController).getPhoneAccount(any());
+
+        mController.isCallingAccountBindToSubscription(null);
+    }
+
+    @Test
+    public void getLabelFromCallingAccount_invalidAccount_emptyString() {
+        doReturn(null).when(mController).getPhoneAccount(any());
+
+        assertThat(mController.getLabelFromCallingAccount(null)).isEqualTo("");
+    }
+
     @Test
     public void displayPreference_twoSubscriptionsSub1Default_correctListPreferenceValues() {
         final SubscriptionInfo sub1 = createMockSub(111, "sub1");