Incall发起notification后，由systemui根据当前手机状态，来决定是显示来电界面还是headsup小窗口。

android7.0 来电UI启动流程.png

• package/app/Dialer -- InCallPresenter
  　接着上篇文章，从onIncomingCall开始查看：

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

关注startOrFinishUi方法，若是满足直接显示UI的条件调用showInCall，直接启动UI；否则调用startUi：

private InCallState startOrFinishUi(InCallState newState) {
    if (showCallUi || showAccountPicker || isAutoAnswer) {
        showInCall(false /* showDialpad */, !showAccountPicker /* newOutgoingCall */);
    } else if (startIncomingCallSequence) {
        if (!startUi(newState)) {
            return mInCallState;
        }
    } 
}

调用StatusBarNotifier.updateNotification：

private boolean startUi(InCallState inCallState) {
    if (isCallWaiting || anyOtherSubActive) {
        if (mProximitySensor.isScreenReallyOff() && isActivityStarted()) {
            mInCallActivity.finish();
            return false;
        } else {
            showInCall(false, false);
        }
    } else {
        mStatusBarNotifier.updateNotification(inCallState, mCallList);
    }
    return true;
}

• package/app/Dialer -- StatusBarNotifier
  incall发起通知，后续由notification决定是显示小窗口还是来电界面：

private void buildAndSendNotification(Call originalCall, ContactCacheEntry contactInfo) {
    Notification.Builder publicBuilder = new Notification.Builder(mContext);
    final PendingIntent inCallPendingIntent = createLaunchPendingIntent();

    if (notificationType == NOTIFICATION_INCOMING_CALL
            && (!InCallPresenter.getInstance().isShowingInCallUi() ||
               (pendingAccountSelectionCall != null))) {
        configureFullScreenIntent(builder, inCallPendingIntent, call);
    }

    Notification notification = builder.build();
    mNotificationManager.notify(notificationType, notification);
}

configureFullScreenIntent方法：

private void configureFullScreenIntent(Notification.Builder builder, PendingIntent intent,

        Call call) {
    // Ok, we actually want to launch the incoming call
    // UI at this point (in addition to simply posting a notification
    // to the status bar).  Setting fullScreenIntent will cause
    // the InCallScreen to be launched immediately *unless* the
    // current foreground activity is marked as "immersive".
    builder.setFullScreenIntent(intent, true);
}

携带intent来启动InCallActivity：

private PendingIntent createLaunchPendingIntent() {

    final Intent intent = InCallPresenter.getInstance().getInCallIntent(
            false /* showDialpad */, false /* newOutgoingCall */);

    // PendingIntent that can be used to launch the InCallActivity.  The
    // system fires off this intent if the user pulls down the windowshade
    // and clicks the notification's expanded view.  It's also used to
    // launch the InCallActivity immediately when when there's an incoming
    // call (see the "fullScreenIntent" field below).
    PendingIntent inCallPendingIntent = PendingIntent.getActivity(mContext, 0, intent, 0);

    return inCallPendingIntent;
}

• frameworks/base/core -- NotificationManager

public void notifyAsUser(String tag, int id, Notification notification, UserHandle user)
{
    INotificationManager service = getService();
    try {
        service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,
                copy, idOut, user.getIdentifier());
    } 
}

• frameworks/base/core -- NotificationManagerService
  　找到INotificationManager aidl实现enqueueNotificationWithTag方法的地方：

private final IBinder mService = new INotificationManager.Stub() {
    @Override
    public void enqueueNotificationWithTag(String pkg, String opPkg, String tag, int id,
            Notification notification, int[] idOut, int userId) throws RemoteException {
        enqueueNotificationInternal(pkg, opPkg, Binder.getCallingUid(),
                Binder.getCallingPid(), tag, id, notification, idOut, userId);
    }

• frameworks/base/packages/SystemUI -- BaseStatusBar

private final NotificationListenerService mNotificationListener =
        new NotificationListenerService() {
    @Override
    public void onNotificationPosted(final StatusBarNotification sbn,
            final RankingMap rankingMap) {
        if (sbn != null) {
            mHandler.post(new Runnable() {
                @Override
                public void run() {
                    if (isUpdate) {
                        updateNotification(sbn, rankingMap);
                    } else {
                        addNotification(sbn, rankingMap, null /* oldEntry */);
                    }
                }
            });

• frameworks/base/packages/SystemUI -- PhoneStatusBar
  isHeadsUped决定是显示headsup还是来电界面：

@Override
public void addNotification(StatusBarNotification notification, RankingMap ranking,
        Entry oldEntry) {

    boolean isHeadsUped = shouldPeek(shadeEntry);
    if (isHeadsUped) {
        mHeadsUpManager.showNotification(shadeEntry);
        setNotificationShown(notification);
    }

    if (!isHeadsUped && notification.getNotification().fullScreenIntent != null) {
            try {
                notification.getNotification().fullScreenIntent.send();
                shadeEntry.notifyFullScreenIntentLaunched();
            }