设置网络首选项

android.provider.Settings.Secure.putInt(mPhone.getContext().getContentResolver(),
                        android.provider.Settings.Secure.PREFERRED_NETWORK_MODE,
                        buttonNetworkMode );
                //Set the modem network mode
                mPhone.setPreferredNetworkType(modemNetworkMode, mHandler
                        .obtainMessage(MyHandler.MESSAGE_SET_PREFERRED_NETWORK_TYPE));