一、概要

无论是在MT (Mobile Termination Call被叫——来电)，还是MO (Mobile Origination Call主叫——去电) 流程中，通话界面上都会显示当前通话的名称( 后文以displayName指代 )。通常情况下，如果是一个陌生号码，则会显示为该陌生号码。如果是已知联系人，则会显示该联系人的名称。当然，在会议电话( Conference Call )的情况下则直接显示”会议电话”。但是，在某些特殊情况下，displayName还会显示诸如”私人号码”、”公用电话”、”未知号码”等。

本文主要分析displayName的获取显示流程及显示”未知号码”的原因

二、查询流程

1、开始查询——CallCardPresenter
displayName是隶属于CallCardFragment的控件，当通话MO/MT流程发起时InCallActivity会显示，此时将会触发CallCardFragment界面更新，在CallCardPresenter的init方法中查询displayName，关键代码如下：
CallCardPresenter.java (\packages\apps\incallui\src\com\android\incallui)

 public void init(Context context, Call call) {
        // Call may be null if disconnect happened already.
        if (call != null) {
            mPrimary = call;
            // start processing lookups right away.
            if (!call.isConferenceCall()) {
                startContactInfoSearch(call, CallEnum.PRIMARY, call.getState() == Call.State.INCOMING);
            } else {
                /// M: Modified this for MTK DSDA feature. @{
                /* Google Code:
                updateContactEntry(null, true);
                */
                updateContactEntry(null, CallEnum.PRIMARY, true);
                /// @}
            }
        }
    }

startContactInfoSearch的具体代码如下：

    /**
     * Starts a query for more contact data for the save primary and secondary calls.
     */
    private void startContactInfoSearch(final Call call, CallEnum type,
            boolean isIncoming) {
        final ContactInfoCache cache = ContactInfoCache.getInstance(mContext);
// ContactInfoCache中开始查找 
        cache.findInfo(call, isIncoming, new ContactLookupCallback(this, type));
    }

2、异步查询——ContactInfoCache
在CallCardPresenter中发起查询之后会跳转到ContactInfoCache.findInfo()方法中，ContactInfoCache不仅用于查询当前通话的相关信息，还可以将这些信息缓存以备下次查询相同信息时快速返回。findInfo关键代码如下：

    /**
     * Requests contact data for the Call object passed in.
     * Returns the data through callback.  If callback is null, no response is made, however the
     * query is still performed and cached.
     *
     * @param callback The function to call back when the call is found. Can be null.
     */
    public void findInfo(final Call call, final boolean isIncoming,
            ContactInfoCacheCallback callback) {
// 查询caller信息，完成之后会回调到FindInfoCallback中，会调用findInfoQueryComplete 
        final CallerInfo callerInfo = CallerInfoUtils.getCallerInfoForCall(
                mContext, call, new FindInfoCallback(isIncoming));
// 当查询完毕之后回调并更新ContactEntry，这里最终会去更新界面显示  
        findInfoQueryComplete(call, callerInfo, isIncoming, false);
    }

CallerInfo中包含了当前call的基本信息，比如号码、类型、特殊相关服务等，在获取到这些信息之后再进行进一步的联系人数据库查询。

3、获取CallerInfo——CallerInfoUtils
在getCallerInfoForCall()方法中，除了获取当前Call的基本信息之外，还会根据当前Call的phoneNumber去数据库中查询，关键代码如下：

ContactInfoCache.java (\packages\apps\incallui\src\com\android\incallui)

    /**
     * This is called to get caller info for a call. This will return a CallerInfo
     * object immediately based off information in the call, but
     * more information is returned to the OnQueryCompleteListener (which contains
     * information about the phone number label, user's name, etc).
     */
    public static CallerInfo getCallerInfoForCall(Context context, Call call,
            CallerInfoAsyncQuery.OnQueryCompleteListener listener) {
// 获取当前Call的基本信息并创建CallerInfo对象 
        CallerInfo info = buildCallerInfo(context, call);
    // 根据phoneNumber在CallerInfoAsyncQuery中开启具体查询  
        if (info.numberPresentation == TelecomManager.PRESENTATION_ALLOWED) {
            // Start the query with the number provided from the call.
            Log.d(TAG, "==> Actually starting CallerInfoAsyncQuery.startQuery()...");
            CallerInfoAsyncQuery.startQuery(QUERY_TOKEN, context, info, listener, call);
        }
        return info;
    }

在以上代码中，有两个重要的方法，即buildCallerInfo()和CallerInfoAsyncQuery.startQuery()，先查询看buildCallerInfo()的关键代码：

   public static CallerInfo buildCallerInfo(Context context, Call call) {
        CallerInfo info = new CallerInfo();
        // Store CNAP information retrieved from the Connection (we want to do this
        // here regardless of whether the number is empty or not).
// 获取当前Call的CNAP name 
        info.cnapName = call.getCnapName();
        info.name = info.cnapName;
        info.numberPresentation = call.getNumberPresentation();
        info.namePresentation = call.getCnapNamePresentation();
        String numbe