packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
/frameworks/base/telephony/java/android/telephony/SubscriptionManager.java
frameworks/ base/telephony/java/android/telephony/CarrierConfigManager.java
===========附上:默认开启或关闭数据流量
SettingsProvider\src\com\android\providers\settings\DatabaseHelper.java