从android 4.1.1 到android 4.2 telephony的变化

 首先，最大的变化是代码路径的变化：

从原来的frameworks/base/telephony 到 frameworks/opt/telephony, 这样，telephony就可以有独立的分支（branch）.

把常量放到一个类文件中

例如把GsmDataConnectionTracker.java中的常量放到DctConstants.java中。

把Phone.java中的常量放到PhoneConstants.java中。

Move the following code from PhoneFactory.java to TelephonyManager.java.

public static int getPhoneType(int networkMode) {
        switch(networkMode) {
        case RILConstants.NETWORK_MODE_CDMA:
        case RILConstants.NETWORK_MODE_CDMA_NO_EVDO:
        case RILConstants.NETWORK_MODE_EVDO_NO_CDMA:
            return Phone.PHONE_TYPE_CDMA;

        case RILConstants.NETWORK_MODE_WCDMA_PREF:
        case RILConstants.NETWORK_MODE_GSM_ONLY:
        case RILConstants.NETWORK_MODE_WCDMA_ONLY:
        case RILConstants.NETWORK_MODE_GSM_UMTS:
            return Phone.PHONE_TYPE_GSM;

        // Use CDMA Phone for the global mode including CDMA
        case RILConstants.NETWORK_MODE_GLOBAL:
        case RILConstants.NETWORK_MODE_LTE_CDMA_EVDO:
        case RILConstants.NETWORK_MODE_LTE_CMDA_EVDO_GSM_WCDMA:
            return Phone.PHONE_TYPE_CDMA;

        case RILConstants.NETWORK_MODE_LTE_ONLY:
            if (BaseCommands.getLteOnCdmaModeStatic() == Phone.LTE_ON_CDMA_TRUE) {
                return Phone.PHONE_TYPE_CDMA;
            } else {
                return Phone.PHONE_TYPE_GSM;
            }
        default:
            return Phone.PHONE_TYPE_GSM;
        }

Move the following code from both of CDMAPhone and GSMPhone to PhoneBase.

public SignalStrength getSignalStrength() {
        return mSST.mSignalStrength;
    }
void  notifySignalStrength() {
        mNotifier.notifySignalStrength(this);
    }

Move the following code from CommandsInterface.java to TelephonyManager.java

public static int getLteOnCdmaModeStatic() {
        int retVal;
        int curVal;
        String productType = "";

        curVal = SystemProperties.getInt(TelephonyProperties.PROPERTY_LTE_ON_CDMA_DEVICE,
                    Phone.LTE_ON_CDMA_UNKNOWN);
        retVal = curVal;
        if (retVal == Phone.LTE_ON_CDMA_UNKNOWN) {
            Matcher matcher = sProductTypePattern.matcher(sKernelCmdLine);
            if (matcher.find()) {
                productType = matcher.group(1);
                if (sLteOnCdmaProductType.equals(productType)) {
                    retVal = Phone.LTE_ON_CDMA_TRUE;
                } else {
                    retVal = Phone.LTE_ON_CDMA_FALSE;
                }
            } else {
                retVal = Phone.LTE_ON_CDMA_FALSE;
            }
        }

        Log.d(LOG_TAG, "getLteOnCdmaMode=" + retVal + " curVal=" + curVal +
                " product_type='" + productType +
                "' lteOnCdmaProductType='" + sLteOnCdmaProductType + "'");
        return retVal;
    }

private static String getProcCmdLine()
    {
        String cmdline = "";
        FileInputStream is = null;
        try {
            is = new FileInputStream("/proc/cmdline");
            byte [] buffer = new byte[2048];
            int count = is.read(buffer);
            if (count > 0) {
                cmdline = new String(buffer, 0, count);
            }
        } catch (IOException e) {
            Log.d(LOG_TAG, "No /proc/cmdline exception=" + e);
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                }
            }
        }
        Log.d(LOG_TAG, "/proc/cmdline=" + cmdline);
        return cmdline;
    }