signal display process

在GsmDataConnectiontracker构造方法中
     p.mSST.registerForGprsAttached(this, EVENT_GPRS_ATTACHED, null);
        p.mSST.registerForGprsDetached(this, EVENT_GPRS_DETACHED, null);
mSST是GsmServiceStateTrack。
    void registerForGprsDetached(Handler h, int what, Object obj) {
        Registrant r = new Registrant(h, what, obj);
        gprsDetachedRegistrants.add(r);

        if (gprsState == ServiceState.STATE_OUT_OF_SERVICE) {
            r.notifyRegistrant();
        }
        }
在mGsmServiceStateTrack中，当收到底层上来的PS注册状态时，执行：
    case EVENT_POLL_STATE_GPRS:
                    states = (String[])ar.result;

                    int type = 0;
                    regState = -1;
                    if (states.length > 0) {
                        try {
                            regState = Integer.parseInt(states[0]);

                            // states[3] (if present) is the current radio technology
                            if (states.length >= 4 && states[3] != null) {
                                type = Integer.parseInt(states[3]);
                            }
                        } catch (NumberFormatException ex) {
                            Log.w(LOG_TAG, "error parsing GprsRegistrationState: " + ex);
                        }
                    }
                    newGPRSState = regCodeToServiceState(regState);
                    mDataRoaming = regCodeIsRoaming(regState);
                    newNetworkType = type;
                    newSS.setRadioTechnology(type);
                break;
然后调用pollStateDone()，方法中：
     if (hasGprsAttached) {
            gprsAttachedRegistrants.notifyRegistrants();
        }

        if (hasGprsDetached) {
            gprsDetachedRegistrants.notifyRegistrants();
        }
然后调用在GsmDataConnectiontracker的方法：
     public void handleMessage (Message msg) {
        if (DBG) Log.d(LOG_TAG,"GSMDataConnTrack handleMessage "+msg);

        if (!mGsmPhone.mIsTheCurrentActivePhone) {
            Log.d(LOG_TAG, "Ignore GSM msgs since GSM phone is inactive");
            return;
        }

        switch (msg.what) {
            case EVENT_RECORDS_LOADED:
                onRecordsLoaded();
                break;

            case EVENT_GPRS_DETACHED:
                onGprsDetached();
                break;

            case EVENT_GPRS_ATTACHED:
                onGprsAttached();
                break;
        }
        private void onGprsAttached() {
        if (state == State.CONNECTED) {
            startNetStatPoll();
            phone.notifyDataConnection(Phone.REASON_GPRS_ATTACHED);
        } else {
            if (state == State.FAILED) {
                cleanUpConnection(false, Phone.REASON_GPRS_ATTACHED);
                mRetryMgr.resetRetryCount();
            }
            trySetupData(Phone.REASON_GPRS_ATTACHED);
        }
        }

        protected void startNetStatPoll() {
        if (state == State.CONNECTED && mPingTestActive == false && netStatPollEnabled == false) {
            Log.d(LOG_TAG, "[DataConnection] Start poll NetStat");
            resetPollStats();
            netStatPollEnabled = true;
            mPollNetStat.run();
        }
        }
    private Runnable mPollNetStat = new Runnable()
        {

        public void run() {
            long sent, received;
            long preTxPkts = -1, preRxPkts = -1;

            Activity newActivity;

            preTxPkts = txPkts;
            preRxPkts = rxPkts;

            txPkts = TrafficStats.getMobileTxPackets();
            rxPkts = TrafficStats.getMobileRxPackets();setupData

            //Log.d(LOG_TAG, "rx " + String.valueOf(rxPkts) + " tx " + String.valueOf(txPkts));

            if (netStatPollEnabled && (preTxPkts > 0 || preRxPkts > 0)) {
                sent = txPkts - preTxPkts;
                received = rxPkts - preRxPkts;

                if ( sent > 0 && received > 0 ) {
                    sentSinceLastRecv = 0;
                    newActivity = Activity.DATAINANDOUT;
                    mPdpResetCount = 0;
                } else if (sent > 0 && received == 0) {
                    if (phone.getState() == Phone.State.IDLE) {
                        sentSinceLastRecv += sent;
                    } else {
                        sentSinceLastRecv = 0;
                    }
                    newActivity = Activity.DATAOUT;
                } else if (sent == 0 && received > 0) {
                    sentSinceLastRecv = 0;
                    newActivity = Activity.DATAIN;
                    mPdpResetCount = 0;
                } else if (sent == 0 && received == 0) {
                    newActivity = Activity.NONE;
                } else {
                    sentSinceLastRecv = 0;
                    newActivity = Activity.NONE;
                }

                if (activity != newActivity && mIsScreenOn) {
                    activity = newActivity;
                    phone.notifyDataActivity();
                }
            }
PhoneBase中：
        public void notifyDataActivity() {
        mNotifier.notifyDataActivity(this);
        }
        public void notifyDataActivity() {
        mNotifier.notifyDataActivity(this);
        }
DefaultPhoneNotifier：
        public void notifyDataActivity(Phone sender) {
        try {
            mRegistry.notifyDataActivity(convertDataActivityState(sender.getDataActivityState()));
        } catch (RemoteException ex) {
            // system process is dead
        }
        }
GsmPhone：
    public DataActivityState getDataActivityState() {
        DataActivityState ret = DataActivityState.NONE;

        if (mSST.getCurrentGprsState() == ServiceState.STATE_IN_SERVICE) {
            switch (mDataConnection.getActivity()) {
                case DATAIN:
                    ret = DataActivityState.DATAIN;
                break;

                case DATAOUT:
                    ret = DataActivityState.DATAOUT;
                break;

                case DATAINANDOUT:
                    ret = DataActivityState.DATAINANDOUT;
                break;
            }
        }

        return ret;
        }
调用DefaultPhoneNotifier：
        public static int convertDataActivityState(Phone.DataActivityState state) {
        switch (state) {
            case DATAIN:
                return TelephonyManager.DATA_ACTIVITY_IN;
            case DATAOUT:
                return TelephonyManager.DATA_ACTIVITY_OUT;
            case DATAINANDOUT:
                return TelephonyManager.DATA_ACTIVITY_INOUT;
            case DORMANT:
                return TelephonyManager.DATA_ACTIVITY_DORMANT;
            default:
                return TelephonyManager.DATA_ACTIVITY_NONE;
        }
        }
调用TelephonyRegister：
     public void notifyDataActivity(int state) {
        369         if (!checkNotifyPermission("notifyDataActivity()" )) {
        370             return;
        371         }
        372         synchronized (mRecords) {
        373             mDataActivity = state;
        374             for (int i = mRecords.size() - 1; i >= 0; i--) {
        375                 Record r = mRecords.get(i);
        376                 if ((r.events & PhoneStateListener.LISTEN_DATA_ACTIVITY) != 0) {
        377                     try {
        378                         r.callback.onDataActivity(state);
        379                     } catch (RemoteException ex) {
        380                         remove(r.binder);
        381                     }
        382                 }
        383             }
        384         }
        385     }

StatusBarPolicy中：
     private PhoneStateListener mPhoneStateListener = new PhoneStateListener() {
        @Override
        public void onDataActivity(int direction) {
            mDataActivity = direction;
            updateDataIcon();
        }
        };
    private final void updateDataIcon() {
        int iconId;
        boolean visible = true;

        if (!isCdma()) {
            // GSM case, we have to check also the sim state
            if (mSimState == IccCard.State.READY || mSimState == IccCard.State.UNKNOWN) {
                if (hasPsService() && mDataState == TelephonyManager.DATA_CONNECTED) {
                    switch (mDataActivity) {
                        case TelephonyManager.DATA_ACTIVITY_IN:
                            iconId = mDataIconList[1];
                            break;
                        case TelephonyManager.DATA_ACTIVITY_OUT:
                            iconId = mDataIconList[2];
                            break;
                        case TelephonyManager.DATA_ACTIVITY_INOUT:
                            iconId = mDataIconList[3];
                            break;
                        default:
                            iconId = mDataIconList[0];
                            break;
                    }
                    mService.setIcon("data_connection", iconId, 0);
                } else {
                    visible = false;
                }
            } else {
                iconId = R.drawable.stat_sys_no_sim;
                mService.setIcon("data_connection", iconId, 0);
            }
        }
        }