彩信是通过http协议发送数据的，因此，要先建立数据通路3G
发彩信时，会自动启动建立3G网络，不好跟代码，还是从设置中跟踪代码简单些
com.android.phone.Settings.java onPreferenceTreeClick -> if (preference == mButtonDataEnabled) - ConnectivityManager.setMobileDataEnabled(true) frameworks/base/core/java/android/net/ConnectivityManager.java setMobileDataEnabled -> ConnectivityService.setMobileDataEnabled frameworks/base/services/java/com/android/server/ConnectivityService.java setMobileDataEnabled -> MyHandler.sendMessage[EVENT_SET_MOBILE_DATA] -> handleMessage EVENT_SET_MOBILE_DATA ->handleSetMobileData -> MobileDataStateTracker.reconnect() frameworks/base/core/java/android/net/MobileDataStateTracker.java reconnect -> setEnableApn -> CompositePhoneInterfaceManager.enableApnType ... frameworks/base/telephony/java/com/android/internal/telephony/DataConnectionTracker.java setEnabled:EVENT_ENABLE_NEW_APN -> handleMessage -> onEnableApn -> onEnableNewApn frameworks/base/telephony/java/com/android/internal/telephony/gsm/GsmDataConnectionTracker.java onEnableNewApn() -> cleanUpConnection -> DataConnection.disconnect[EVENT_DISCONNECT_DONE] -> onDisconnectDone -> trySetupData ->setupData -> DataConnection.connect EVENT_CONNECT -> CdmaDataConnection.onConnect -> phone.mCM.setupDataCall