我們先看下7.0來電大體流程：

##Framework

modem接收到來電通知訊息後，以AT指令的方式上報RIL層，RIL層通過sokcet將訊息傳送給RILJ， 上報事件ID: RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED：

• frameworks/opt/telephony – RIL

   　private void　processUnsolicited (Parcel p, int type) {
           case RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED:
                if (RILJ_LOGD) unsljLog(response);
                mCallStateRegistrants
                    .notifyRegistrants(new AsyncResult(null, null, null));
            break;
 

• frameworks/opt/telephony – BaseCommands mCallStateRegistrants在BaseCommands中新增的觀察者方法，在GsmCdmaCallTracker中註冊了registerForCallStateChanged方法：

    @Override
    public void registerForCallStateChanged(Handler h, int what, Object obj) {
        Registrant r = new Registrant (h, what, obj);
        mCallStateRegistrants.add(r);
    }
 

• frameworks/opt/telephony – GsmCdmaCallTracker

  　public GsmCdmaCallTracker (GsmCdmaPhone phone) {
        mCi = phone.mCi;
        mCi.registerForCallStateChanged(this, EVENT_CALL_STATE_CHANGE, null);

接著找到EVENT_CALL_STATE_CHANGE訊息：

            case EVENT_CALL_STATE_CHANGE:
                pollCallsWhenSafe();
            break;
 

• frameworks/opt/telephony – CallTracker 找到GsmCdmaCallTracker父類的方法pollCallsWhenSafe：

    protected void pollCallsWhenSafe() {
        mNeedsPoll = true;
        if (checkNoOperationsPending()) {
            mLastRelevantPoll = obtainMessage(EVENT_POLL_CALLS_RESULT);
            mCi.getCurrentCalls(mLastRelevantPoll);
        }
    }

• frameworks/opt/telephony – RIL 找到CommandsInterface mCi，而其RIL implements CommandsInterface實現了getCurrentCalls方法，，攜帶訊息 EVENT_POLL_CALLS_RESULT：

    @Override
    public void getCurrentCalls (Message result) {
        RILRequest rr = RILRequest.obtain(RIL_REQUEST_GET_CURRENT_CALLS, result);
        if (RILJ_LOGD) riljLog(rr.serialString() + "> " + requestToString(rr.mRequest));
        send(rr);
    }

• frameworks/opt/telephony – GsmCdmaCallTracker 和之前流程類似，接著進入handlePollCalls方法：

 case EVENT_POLL_CALLS_RESULT:
                Rlog.d(LOG_TAG, "Event EVENT_POLL_CALLS_RESULT Received");
                if (msg == mLastRelevantPoll) {
                    if (DBG_POLL) log(
                            "handle EVENT_POLL_CALL_RESULT: set needsPoll=F");
                    mNeedsPoll = false;
                    mLastRelevantPoll = null;
                    handlePollCalls((AsyncResult)msg.obj);
                }

更新狀態，傳送call state change通知等：

　    if (newRinging != null) {
            mPhone.notifyNewRingingConnection(newRinging);
         }
        updatePhoneState();
        if (hasNonHangupStateChanged || newRinging != null || hasAnyCallDisconnected) {
            mPhone.notifyPreciseCallStateChanged();
        }

• frameworks/opt/telephony –　Phone notifyNewRingingConnectionP方法：

    /**
     * Notify registrants of a new ringing Connection.
     * Subclasses of Phone probably want to replace this with a
     * version scoped to their packages
     */
    public void notifyNewRingingConnectionP(Connection cn) {
        if (!mIsVoiceCapable)
            return;
        AsyncResult ar = new AsyncResult(null, cn, null);
        mNewRingingConnectionRegistrants.notifyRegistrants(ar);
    }

##Telephony

• packages/service/Telephony – PstnIncomingCallNotifier 找到註冊registerForNewRingingConnection處, 訊息EVENT_NEW_RINGING_CONNECTION呼叫handleNewRingingConnection：

         mPhone.registerForNewRingingConnection(mHandler, EVENT_NEW_RINGING_CONNECTION, null);

        　case EVENT_NEW_RINGING_CONNECTION:
               handleNewRingingConnection((AsyncResult) msg.obj);
               break;

##Framework

• frameworks/base/telecomm – TelecomManager addNewIncomingCall方法

public void addNewIncomingCall(PhoneAccountHandle phoneAccount, Bundle extras) {
        try {
            if (isServiceConnected()) {
                getTelecomService().addNewIncomingCall(
                        phoneAccount, extras == null ? new Bundle() : extras);
            }
        } catch (RemoteException e) {
            Log.e(TAG, "RemoteException adding a new incoming call: " + phoneAccount, e);
        }
    }

##Telecom

• packages/services/Telecom – TelecomServiceImpl 找到對應的ITelecomServic aidl接收的地方，檢視addNewIncomingCall方法：

  private final ITelecomService.Stub mBinderImpl = new ITelecomService.Stub() {
   @Override
        public void addNewIncomingCall(PhoneAccountHandle phoneAccountHandle, Bundle extras) {
              Intent intent = new Intent(TelecomManager.ACTION_INCOMING_CALL);
                            intent.putExtra(TelecomManager.EXTRA_PHONE_ACCOUNT_HANDLE,
                                    phoneAccountHandle);
              intent.putExtra(CallIntentProcessor.KEY_IS_INCOMING_CALL, true);
              if (extras != null) {
                       extras.setDefusable(true);
                                intent.putExtra(TelecomManager.EXTRA_INCOMING_CALL_EXTRAS, extras);
                            }
             mCallIntentProcessorAdapter.processIncomingCallIntent(
                                    mCallsManager, intent); 

• packages/services/Telecom – CallIntentProcessor

    static void processIncomingCallIntent(CallsManager callsManager, Intent intent) {
        callsManager.processIncomingCallIntent(phoneAccountHandle, clientExtras);
    }

• packages/services/Telecom – CallsManager 建立call之後，CreateConnection建立連結，之後的流程和撥出流程類似：

   void processIncomingCallIntent(PhoneAccountHandle phoneAccountHandle, Bundle extras) {
        Call call = new Call(
                getNextCallId(),
                mContext,
                this,
                mLock,
                mConnectionServiceRepository,
                mContactsAsyncHelper,
                mCallerInfoAsyncQueryFactory,
                handle,
                null /* gatewayInfo */,
                null /* connectionManagerPhoneAccount */,
                phoneAccountHandle,
                Call.CALL_DIRECTION_INCOMING /* callDirection */,
                false /* forceAttachToExistingConnection */,
                false /* isConference */
        );
        call.addListener(this);
        call.startCreateConnection(mPhoneAccountRegistrar);
    }

• packages/services/Telecom – Call

void startCreateConnection(PhoneAccountRegistrar phoneAccountRegistrar) {
    mCreateConnectionProcessor = new CreateConnectionProcessor(this, mRepository, this,
            phoneAccountRegistrar, mContext);
    mCreateConnectionProcessor.process();
}

• packages/services/Telecom – CreateConnectionProcessor

@VisibleForTesting
public void process() {
    Log.v(this, "process");
    clearTimeout();
    mAttemptRecords = new ArrayList<>();
    if (mCall.getTargetPhoneAccount() != null) {
        mAttemptRecords.add(new CallAttemptRecord(
                mCall.getTargetPhoneAccount(), mCall.getTargetPhoneAccount()));
    }
    adjustAttemptsForConnectionManager();
    adjustAttemptsForEmergency();
    mAttemptRecordIterator = mAttemptRecords.iterator();
    attemptNextPhoneAccount();
}

• packages/services/Telecom – ConnectionServiceWrapper

mServiceInterface.createConnection(

        call.getConnectionManagerPhoneAccount(),
        callId,
        new ConnectionRequest(
                call.getTargetPhoneAccount(),
                call.getHandle(),
                extras,
                call.getVideoState(),
                callId),
        call.shouldAttachToExistingConnection(),
        call.isUnknown());

##Frameworks

• frameworks/base/telecomm – ConnectionService 撥出時是呼叫onCreateOutgoingConnection，此篇是呼入，需要檢視onCreateIncomingConnection

Connection connection = isUnknown ? onCreateUnknownConnection(callManagerAccount, request)
        : isIncoming ? onCreateIncomingConnection(callManagerAccount, request)
        : onCreateOutgoingConnection(callManagerAccount, request);

##Telecom

• packages/services/Telecom – Call

　public void handleCreateConnectionSuccess(
    switch (mCallDirection) {
        case CALL_DIRECTION_INCOMING:
            // Listeners (just CallsManager for now) will be responsible for checking whether
            // the call should be blocked.
            for (Listener l : mListeners) {
                l.onSuccessfulIncomingCall(this);
            }
            break;

• packages/services/Telecom – CallsManager

@Override
public void onSuccessfulIncomingCall(Call incomingCall) {
    Log.d(this, "onSuccessfulIncomingCall");
    List<IncomingCallFilter.CallFilter> filters = new ArrayList<>();
    filters.add(new DirectToVoicemailCallFilter(mCallerInfoLookupHelper));
    filters.add(new AsyncBlockCheckFilter(mContext, new BlockCheckerAdapter()));
    filters.add(new CallScreeningServiceFilter(mContext, this, mPhoneAccountRegistrar,
            mDefaultDialerManagerAdapter,
            new ParcelableCallUtils.Converter(), mLock));
    new IncomingCallFilter(mContext, this, incomingCall, mLock,
            mTimeoutsAdapter, filters).performFiltering();
}

• packages/services/Telecom – IncomingCallFilter 主要執行關於攔截來電的，是否是黑名單等資訊，此篇不關注此處流程：

public void performFiltering() {
    mHandler.postDelayed(new Runnable("ICF.pFTO") { // performFiltering time-out
        @Override
        public void loggedRun() {
            // synchronized to prevent a race on mResult and to enter into Telecom.
            synchronized (mTelecomLock) {
                if (mIsPending) {
                    Log.i(IncomingCallFilter.this, "Call filtering has timed out.");
                    Log.event(mCall, Log.Events.FILTERING_TIMED_OUT);
                    mListener.onCallFilteringComplete(mCall, mResult);
                    mIsPending = false;
                }
            }
        }
    }.prepare(), mTimeoutsAdapter.getCallScreeningTimeoutMillis(mContext.getContentResolver()));
}

• packages/services/Telecom – CallsManager

   @Override
   public void onCallFilteringComplete(Call incomingCall, CallFilteringResult result) {
          addCall(incomingCall);
      }

    private void addCall(Call call) {
        for (CallsManagerListener listener : mListeners) {
            listener.onCallAdded(call)；}

• packages/services/Telecom – InCallController 和呼入篇類似，附相關程式碼：

@Override
public void onCallAdded(Call call) {
    if (!isBoundToServices()) {
        bindToServices(call);
    } else {
        addCall(call);
        inCallService.addCall(parcelableCall);
}

##Frameworks

• frameworks/base/telecomm – InCallService 實現aidl方法addCall，找到訊息MSG_ADD_CALL:

private final class InCallServiceBinder extends IInCallService.Stub {
    @Override
    public void setInCallAdapter(IInCallAdapter inCallAdapter) {
        mHandler.obtainMessage(MSG_SET_IN_CALL_ADAPTER, inCallAdapter).sendToTarget();
    }

    @Override
    public void addCall(ParcelableCall call) {
        mHandler.obtainMessage(MSG_ADD_CALL, call).sendToTarget();
    }

    case MSG_ADD_CALL:
    mPhone.internalAddCall((ParcelableCall) msg.obj);
    break;

• frameworks/base/telecomm – Phone

final void internalAddCall(ParcelableCall parcelableCall) {
    Call call = new Call(this, parcelableCall.getId(), mInCallAdapter,
            parcelableCall.getState());
    mCallByTelecomCallId.put(parcelableCall.getId(), call);
    mCalls.add(call);
    checkCallTree(parcelableCall);
    call.internalUpdate(parcelableCall, mCallByTelecomCallId);
    fireCallAdded(call);
 }

private void fireCallAdded(Call call) {
    for (Listener listener : mListeners) {
        listener.onCallAdded(this, call);
    }
}

• frameworks/base/telecomm – InCallService

@Override
public void onCallAdded(Phone phone, Call call) {
    InCallService.this.onCallAdded(call);
}

##Dialer

• packages/app/Dialer – InCallServiceImpl

@Override
public void onCallAdded(Call call) {
   InCallPresenter.getInstance().onCallAdded(call);}

• packages/app/Dialer – InCallPresenter

public void onCallAdded(final android.telecom.Call call) {
    if (shouldAttemptBlocking(call)) {
        maybeBlockCall(call);
    } else {
        mCallList.onCallAdded(call);
    }
}

@Override
public void onIncomingCall(Call call) {
    InCallState newState = startOrFinishUi(InCallState.INCOMING);
    InCallState oldState = mInCallState;
    for (IncomingCallListener listener : mIncomingCallListeners) {
        listener.onIncomingCall(oldState, mInCallState, call);
    }
}