VoLTE 注册流程

1、开关按钮位置：

  设置--> 更多--> 移动网络--> 增强型4G LTE模式

2、该设置开关使用了SwitchPreference控件，addEnhanced4GLteSwitchPreference()添加控件：

　  packages/services/telephony/src/com/android/phone/MobileNetworkSettings.java

    private void addEnhanced4GLteSwitchPreference(PreferenceScreen preferenceScreen) {
        log("[addEnhanced4GLteSwitchPreference] ImsEnabled :"
                + ImsManager.isVolteEnabledByPlatform(this));
        if (mButton4glte != null) { //去掉Google原生开关按钮
            log("[addEnhanced4GLteSwitchPreference] Remove mButton4glte!");
            preferenceScreen.removePreference(mButton4glte);
        }
        if (ImsManager.isVolteEnabledByPlatform(this)) { //判断是否支持VoLTE
            int order = mButtonEnabledNetworks.getOrder() + 1;
       //VoLTE开关初始化
            mEnhancedButton4glte = new Enhanced4GLteSwitchPreference(this, mPhone.getSubId());
            /// Still use Google's key, title, and summary.
            mEnhancedButton4glte.setKey(BUTTON_4G_LTE_KEY); //Key用于SharePreference存储信息
            if (ImsManager.isWfcEnabledByPlatform(this)) { //判断是否支持WIFI Call
                mEnhancedButton4glte.setTitle(R.string.wfc_volte_switch_title);
            } else {
                mEnhancedButton4glte.setTitle(R.string.enhanced_4g_lte_mode_title);
            }
            mEnhancedButton4glte.setSummary(R.string.enhanced_4g_lte_mode_summary);
            mEnhancedButton4glte.setOnPreferenceChangeListener(this); //设置监听接口，状态发生变化onPreferenceChange()方法将被调用
            mEnhancedButton4glte.setOrder(order);
            //preferenceScreen.addPreference(mEnhancedButton4glte);
        }

3、该接听方法是onPreferenceChangeMTK()，重新原生onPreferenceChange()：

    private boolean onPreferenceChangeMTK(Preference preference, Object objValue) {
        log("[onPreferenceChangeMTK] preference = " + preference.getTitle());
        if (mEnhancedButton4glte == preference) {
            log("[onPreferenceChangeMTK] IsChecked = " + mEnhancedButton4glte.isChecked());
            Enhanced4GLteSwitchPreference ltePref = (Enhanced4GLteSwitchPreference) preference;
            ltePref.setChecked(!ltePref.isChecked()); //设置控件状态，默认关闭是false，打开即是true
            ImsManager.setEnhanced4gLteModeSetting(this, ltePref.isChecked()); //设置VoLTE参数
            return true;
        }
        return false;
    }

有如下打印信息：

4、设置VoLTE状态setEnhanced4gLteModeSetting

　  frameworks/opt/net/ims/src/java/com/android/ims/ImsManager.java

    public static void setEnhanced4gLteModeSetting(Context context, boolean enabled) {
        int value = enabled ? 1 : 0;
          //设置Settings.Global.ENHANCED_4G_MODE_ENABLED变量
        android.provider.Settings.Global.putInt(
                context.getContentResolver(),
                android.provider.Settings.Global.ENHANCED_4G_MODE_ENABLED, value);

        if (isNonTtyOrTtyOnVolteEnabled(context)) { //不支持TTY或者VoLTE支持TTY
            ImsManager imsManager = ImsManager.getInstance(context,
                    SubscriptionManager.getDefaultVoicePhoneId()); //获取ImsManager对象
            if (imsManager != null) {
                try {
                    imsManager.setAdvanced4GMode(enabled); //设置VoLTE
                } catch (ImsException ie) {
                    // do nothing
                }
            }
        }
    }

    //设置VoLTE
    private void setAdvanced4GMode(boolean turnOn) throws ImsException {
        checkAndThrowExceptionIfServiceUnavailable();

        try {
            ImsConfig config = getConfigInterface(); //IMS 配置参数
            if (config != null) {
                             //设置FeatureConstants.FEATURE_TYPE_VOICE_OVER_LTE网络参数
                config.setFeatureValue(ImsConfig.FeatureConstants.FEATURE_TYPE_VOICE_OVER_LTE,
                        TelephonyManager.NETWORK_TYPE_LTE, turnOn ? 1 : 0, null);
            }
        } catch (ImsException e) {
            log("setAdvanced4GMode() : " + e);
        }

        log("setAdvanced4GMode():" + turnOn);
        if (turnOn) {
            turnOnIms(); //打开IMS 服务
        } else if (isImsTurnOffAllowed()) {
            log("setAdvanced4GMode() : imsServiceAllowTurnOff -> turnOffIms");
            turnOffIms(); //关闭IMS 服务
        }

有如下打印信息：

5、打开IMS 服务

    private void turnOnIms() throws ImsException {
        checkAndThrowExceptionIfServiceUnavailable();

        try {
            mImsService.turnOnIms(mPhoneId);
        } catch (RemoteException e) {
            throw new ImsException("turnOnIms() ", e, ImsReasonInfo.CODE_LOCAL_IMS_SERVICE_DOWN);
        }
    }

mImsService 是IImsService 的实例对象，该对象在createImsService()中创建：

       //绑定IMS Service
    private void createImsService(boolean checkService) {
        if (checkService) { //判断IMS Service 服务是否已经存在
            IBinder binder = ServiceManager.checkService(getImsServiceName(mPhoneId));

            if (binder == null) {
                /// M: add for debug @{
                if (DBG) log("ImsManager: createImsService binder is null");
                /// @}
                return;
            }
        }
        //获取指向Service的IBinder对象
        IBinder b = ServiceManager.getService(getImsServiceName(mPhoneId));

        if (b != null) {
            try {
                b.linkToDeath(mDeathRecipient, 0);
            } catch (RemoteException e) {
            }
        }

        mImsService = IImsService.Stub.asInterface(b);
        /// M: add for debug @{
        if (DBG) log("ImsManager: mImsService = " + mImsService);
        /// @}
        }

getImsServiceName()获取IMS Service 名：

    private static String getImsServiceName(int phoneId) {
        // TODO: MSIM implementation needs to decide on service name as a function of phoneId
        return IMS_SERVICE;  //服务名即"ims"
    }

而getImsServiceName()方法在ImsManager类的构造方法中即被调用，所以mImsService对象开机即获取到。

6、调用mImsService的turnOnIms()方法在IImsService.Stub继承类中实现：

vendor/mediatek/proprietary/packages/services/ims/src/com/mediatek/ims/ImsService.java

    /**
     * Used for turning on IMS when its in OFF state.
     */
    @Override
    public void turnOnIms(int phoneId) {
        Rlog.d(LOG_TAG, "turnOnIms, mActivePhoneId = " + mActivePhoneId +
            " phoneId = " + phoneId);
        phoneId = getMainCapabilityPhoneId();
        Rlog.d(LOG_TAG, "turnOnIms, MainCapabilityPhoneId = " + phoneId);

        if (mActivePhoneId != phoneId) {
            mActivePhoneId = phoneId;
        }
    }

   /**
    * to get main capability phone id.
    *
    * @return The phone id with highest capability.
    */
   private int getMainCapabilityPhoneId() { //此接口可能获取主卡phoneID
             //获取服务"phoneEx"
       ITelephonyEx telephony = ITelephonyEx.Stub.asInterface(
               ServiceManager.getService(mContext.TELEPHONY_SERVICE_EX));

       if (telephony != null) {
           try {
               int mainPhoneId = telephony.getMainCapabilityPhoneId(); //调用getMainCapabilityPhoneId()方法
               Rlog.d(LOG_TAG, "getMainCapabilityPhoneId: mainPhoneId = " + mainPhoneId);
               return mainPhoneId;
           }
           ..........
       }
   }

有如下打印信息：

7、获取主PhoneID

PhoneInterfaceManagerEx extends ITelephonyEx.Stub；
    packages/services/telephony/src/com/mediatek/phone/PhoneInterfaceManagerEx.java

    /**
     * Get main capability phone id.
     * @return The phone id with highest capability.
     */
    public int getMainCapabilityPhoneId() {
        return RadioCapabilitySwitchUtil.getMainCapabilityPhoneId();
    }

frameworks/opt/telephony/src/java/com/mediatek/internal/telephony/RadioCapabilitySwitchUtil.java

    /**
     * Get main capability phone ID.
     *
     * @return Phone ID with main capability
     */
    public static int getMainCapabilityPhoneId() {
        int phoneId = 0;
        if (SystemProperties.getBoolean("ro.mtk_dt_support", false) == true) {
            int swapMode = SystemProperties.getInt("persist.ril.simswitch.swapmode", 3);
            if (swapMode == SIM_SWITCH_MODE_DUAL_TALK) {
                phoneId = 0;
            } else if (swapMode == SIM_SWITCH_MODE_DUAL_TALK_SWAP) {
                phoneId = 1;
            }
        } else {
            phoneId = SystemProperties.getInt(PhoneConstants.PROPERTY_CAPABILITY_SWITCH, 1) - 1;
        }
        if (CdmaFeatureOptionUtils.isCdmaLteDcSupport()) {
            if (phoneId == PhoneConstants.SIM_ID_1) {
                if (SvlteUtils.getSvltePhoneProxy(phoneId).getActivePhone().
                    getPhoneName()== "CDMA") {
                    // for svlte project, we need re-mapping slot 0 to DC phone
                    phoneId = SubscriptionManager.LTE_DC_PHONE_ID_1;
                }
            }
            if (phoneId == PhoneConstants.SIM_ID_2) {
                if (SvlteUtils.getSvltePhoneProxy(phoneId).getActivePhone().
                    getPhoneName()== "CDMA") {
                    // for svlte project, we need re-mapping slot 1 to DC phone
                    phoneId = SubscriptionManager.LTE_DC_PHONE_ID_2;
                }
            }
        }
        Log.d(LOG_TAG, "[RadioCapSwitchUtil] getMainCapabilityPhoneId " + phoneId);
        return phoneId;