出處: http://blog.csdn.net/tony_anmoo/article/details/18707015
修改系统属性：ro.telephony.default_network
修改说明：
可连续给两个值（如4，1），卡1用的是4，卡2用的是1。数字代表的意义见下方的相关代码片段。
相关源码位置：
frameworks/base/telephony/java/com/android/internal/telephony/RILConstants.java
frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
相关代码片段：
- /* NETWORK_MODE_* See ril.h RIL_REQUEST_SET_PREFERRED_NETWORK_TYPE */
- int NETWORK_MODE_WCDMA_PREF = 0; /* GSM/WCDMA (WCDMA preferred) */
- int NETWORK_MODE_GSM_ONLY = 1; /* GSM only */
- int NETWORK_MODE_WCDMA_ONLY = 2; /* WCDMA only */
- int NETWORK_MODE_GSM_UMTS = 3; /* GSM/WCDMA (auto mode, according to PRL)
- AVAILABLE Application Settings menu*/
- int NETWORK_MODE_CDMA = 4; /* CDMA and EvDo (auto mode, according to PRL)
- AVAILABLE Application Settings menu*/
- int NETWORK_MODE_CDMA_NO_EVDO = 5; /* CDMA only */
- int NETWORK_MODE_EVDO_NO_CDMA = 6; /* EvDo only */
- int NETWORK_MODE_GLOBAL = 7; /* GSM/WCDMA, CDMA, and EvDo (auto mode, according to PRL)
- AVAILABLE Application Settings menu*/
- int NETWORK_MODE_LTE_CDMA_EVDO = 8; /* LTE, CDMA and EvDo */
- int NETWORK_MODE_LTE_GSM_WCDMA = 9; /* LTE, GSM/WCDMA */
- int NETWORK_MODE_LTE_CMDA_EVDO_GSM_WCDMA = 10; /* LTE, CDMA, EvDo, GSM/WCDMA */
- int NETWORK_MODE_LTE_ONLY = 11; /* LTE Only mode. */
- int NETWORK_MODE_LTE_WCDMA = 12; /* LTE/WCDMA */
- int NETWORK_MODE_TD_SCDMA_ONLY = 13; /* TD-SCDMA only */
- int NETWORK_MODE_TD_SCDMA_WCDMA = 14; /* TD-SCDMA and WCDMA */
- int NETWORK_MODE_TD_SCDMA_LTE = 15; /* TD-SCDMA and LTE */
- int NETWORK_MODE_TD_SCDMA_GSM = 16; /* TD-SCDMA and GSM */
- int NETWORK_MODE_TD_SCDMA_GSM_LTE = 17; /* TD-SCDMA,GSM and LTE */
- int NETWORK_MODE_TD_SCDMA_GSM_WCDMA = 18; /* TD-SCDMA, GSM/WCDMA */
- int NETWORK_MODE_TD_SCDMA_WCDMA_LTE = 19; /* TD-SCDMA, WCDMA and LTE */
- int NETWORK_MODE_TD_SCDMA_GSM_WCDMA_LTE = 20; /* TD-SCDMA, GSM/WCDMA and LTE */
- int NETWORK_MODE_TD_SCDMA_CDMA_EVDO_GSM_WCDMA = 21; /*TD-SCDMA,EvDo,CDMA,GSM/WCDMA*/
- int NETWORK_MODE_TD_SCDMA_LTE_CDMA_EVDO_GSM_WCDMA = 22; /* TD-SCDMA/LTE/GSM/WCDMA, CDMA, and
- EvDo */
- // Set the preferred network mode
- int defaultNetworkType = RILConstants.PREFERRED_NETWORK_MODE;
- int numPhones = MSimTelephonyManager.getDefault().getPhoneCount();
- String networkMode = SystemProperties.get(“ro.telephony.default_network”);
- if (networkMode != null) {
- if (numPhones == MSimConstants.MAX_PHONE_COUNT_SINGLE_SIM) {
- loadSetting(
- stmt,
- Settings.Global.PREFERRED_NETWORK_MODE,
- MSimTelephonyManager.getTelephonyProperty(
- “ro.telephony.default_network”, 0,
- Integer.toString(defaultNetworkType)));
- } else {
- loadSetting(stmt, Settings.Global.PREFERRED_NETWORK_MODE, networkMode);
- }
- } else {
- StringBuilder sb = new StringBuilder(defaultNetworkType);
- for (int i = 0; i < numPhones – 1; i++) {
- sb.append(“,”);
- sb.append(RILConstants.NETWORK_MODE_GSM_ONLY);
- }
- loadSetting(stmt, Settings.Global.PREFERRED_NETWORK_MODE, sb.toString());
- }