Add new system API constant DEFAULT_PREFERRED_NETWORK_MODE

Bug: 140768340
Test: Following tests have been done
atest packages/services/Telephony/tests/
atest frameworks/opt/telephony/tests/telephonytests/
Manual sanity to check basic telephony

Change-Id: Ia114e4546d88e294ed37b6632a1eae6a06fbf7bc

api/system-current.txt

@@ -10726,6 +10726,7 @@ package android.telephony {
     field public static final int CDMA_SUBSCRIPTION_NV = 1; // 0x1
     field public static final int CDMA_SUBSCRIPTION_RUIM_SIM = 0; // 0x0
     field public static final int CDMA_SUBSCRIPTION_UNKNOWN = -1; // 0xffffffff
+    field public static final int DEFAULT_PREFERRED_NETWORK_MODE = 0; // 0x0
     field public static final String EXTRA_ANOMALY_DESCRIPTION = "android.telephony.extra.ANOMALY_DESCRIPTION";
     field public static final String EXTRA_ANOMALY_ID = "android.telephony.extra.ANOMALY_ID";
     field @Deprecated public static final String EXTRA_APN_PROTOCOL = "apnProto";

packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java

@@ -2554,7 +2554,7 @@ class DatabaseHelper extends SQLiteOpenHelper {
             for (int phoneId = 0; phoneId < phoneCount; phoneId++) {
                 int mode = defaultNetworks.size() <= phoneId
                         || defaultNetworks.get(phoneId) == null
-                        ? RILConstants.PREFERRED_NETWORK_MODE : defaultNetworks.get(phoneId);
+                        ? TelephonyManager.DEFAULT_PREFERRED_NETWORK_MODE : defaultNetworks.get(phoneId);
                 if (phoneId > 0) val.append(',');
                 val.append(mode);
             }

telephony/java/android/telephony/TelephonyManager.java

@@ -7648,6 +7648,18 @@ public class TelephonyManager {
     public static final int NETWORK_MODE_NR_LTE_TDSCDMA_CDMA_EVDO_GSM_WCDMA =
             RILConstants.NETWORK_MODE_NR_LTE_TDSCDMA_CDMA_EVDO_GSM_WCDMA;
 
+    /**
+     * The default preferred network mode constant.
+     *
+     * <p> This constant is used in case of nothing is set in
+     * TelephonyProperties#default_network().
+     *
+     * @hide
+     */
+    @SystemApi
+    public static final int DEFAULT_PREFERRED_NETWORK_MODE =
+            RILConstants.DEFAULT_PREFERRED_NETWORK_MODE;
+
     /**
      * Get the preferred network type.
      * Used for device configuration by some CDMA operators.

telephony/java/com/android/internal/telephony/RILConstants.java

@@ -233,11 +233,14 @@ public interface RILConstants {
     /** NR 5G, LTE, TD-SCDMA, CDMA, EVDO, GSM and WCDMA */
     int NETWORK_MODE_NR_LTE_TDSCDMA_CDMA_EVDO_GSM_WCDMA = 33;
 
+    /** Default preferred network mode */
+    int DEFAULT_PREFERRED_NETWORK_MODE = NETWORK_MODE_WCDMA_PREF;
+
     @UnsupportedAppUsage
     int PREFERRED_NETWORK_MODE = Optional.of(TelephonyProperties.default_network())
             .filter(list -> !list.isEmpty())
             .map(list -> list.get(0))
-            .orElse(NETWORK_MODE_WCDMA_PREF);
+            .orElse(DEFAULT_PREFERRED_NETWORK_MODE);
 
     int BAND_MODE_UNSPECIFIED = 0;      //"unspecified" (selected by baseband automatically)
     int BAND_MODE_EURO = 1;             //"EURO band" (GSM-900 / DCS-1800 / WCDMA-IMT-2000)