需求是創(chuàng)建一個(gè)VC，創(chuàng)建后賦值參數(shù)，然后VC內(nèi)部方法將利用此VC初始化時(shí)被賦值的全局變量作為參數(shù)進(jìn)行網(wǎng)絡(luò)請(qǐng)求，初始化如下：

1- (FlightDomesticFreeViewController *)freeDomesticFlightViewController
2{
3  if (_freeDomesticFlightViewController) {
4       return _freeDomesticFlightViewController;
5    }
6   _freeDomesticFlightViewController = [[TNBoss3FlightDomesticFreeViewController alloc] init];
7   _freeDomesticFlightViewController.adultNum = self.adultNum;
8   _freeDomesticFlightViewController.childNum = self.childNum;
9   _freeDomesticFlightViewController.currentSeqNum = 1;
10  _freeDomesticFlightViewController.baseSinglePriceArray = self.baseSinglePriceArray;
11  _freeDomesticFlightViewController.basePackagePrice = self.basePackagePrice;
12   _freeDomesticFlightViewController.productInfo = self.freeFlightInfoDict[PRODUCT_INFO];
13   _freeDomesticFlightViewController.selectedFlights = self.freeFlightInfoDict[SELECT_FLIGHT];
14    _freeDomesticFlightViewController.departureCityCode = self.freeFlightInfoDict[DEPARTURE_CITY_CODE];
15   _freeDomesticFlightViewController.backCityCode = self.freeFlightInfoDict[BACK_CITY_CODE];
16   _freeDomesticFlightViewController.queryFlight = self.queryFlight;
17   _freeDomesticFlightViewController.bookCity = self.bookCity;
18   _freeDomesticFlightViewController.delegate = self;
19   _freeDomesticFlightViewController.isChangeOrder = self.isChangeOrder;
20   _freeDomesticFlightViewController.view.frame = self.freeContentView.bounds;
21   _freeDomesticFlightViewController.journeyId = self.baseInfo.journeyId;
22   [_freeContentView addSubview:_freeDomesticFlightViewController.view];
    
23   [self addChildViewController:_freeDomesticFlightViewController];
24    return _freeDomesticFlightViewController;
}

然后測(cè)試告訴我入?yún)](méi)有journeyId這個(gè)字段，后來(lái)經(jīng)過(guò)反復(fù)斷點(diǎn)調(diào)試，發(fā)現(xiàn)20行執(zhí)行完以后便會(huì)調(diào)入VC的內(nèi)部方法，進(jìn)行網(wǎng)絡(luò)請(qǐng)求，而此時(shí)21行journeyId還未賦值，所以導(dǎo)致入?yún)⒋俗侄螢榭铡Ｔ蚓褪且驗(yàn)?0行執(zhí)行后，VC的viewDidLoad會(huì)執(zhí)行，也就是開(kāi)始執(zhí)行VC的內(nèi)部方法，故這種初始化屬性方式不可在設(shè)置frame方法后，也就是將21行代碼放在20行之前，便可避免這種低級(jí)錯(cuò)誤。