Multithreading and NSNotification in iOS -

i wrote few functions in appdelegate.m this:

- (bool)application:(uiapplication *)application didfinishlaunchingwithoptions:(nsdictionary *)launchoptions {     debugmethod();     self.weibostatusesdatabasecontext = [self createmainqueuemanagedobjectcontext];     return yes; }  - (void)setweibostatusesdatabasecontext:(nsmanagedobjectcontext *)weibostatusesdatabasecontext {     debugmethod();     _weibostatusesdatabasecontext = weibostatusesdatabasecontext;     nsdictionary *userinfo = self.weibostatusesdatabasecontext ? @{weibostatusesdatabaseavailabilitycontext : self.weibostatusesdatabasecontext} : nil;     [[nsnotificationcenter defaultcenter] postnotificationname:weibostatusesdatabaseavailabilitynotification                                                     object:self                                                   userinfo:userinfo]; } 

and wrote function in mainpagecdtvc.m coredata tableviewcontroller :

- (void)awakefromnib {     debugmethod();     [[nsnotificationcenter defaultcenter] addobserverforname:weibostatusesdatabaseavailabilitynotification                                                   object:nil                                                    queue:nil                                               usingblock:^(nsnotification *note) {                                                   self.managedobjectcontext = note.userinfo[weibostatusesdatabaseavailabilitycontext];                                                   debuglog(@"context = %@", self.managedobjectcontext);                                               }];     debuglog(@"context = %@", self.managedobjectcontext); }   

when set mainpagecdtvc initial viewcontroller , run app, got result xcode console :

2015-04-02 11:37:38.650 weibodemo[962:48379] -[mainpagecdtvc awakefromnib] 2015-04-02 11:37:38.665 weibodemo[962:48379] context = (null) 2015-04-02 11:37:38.669 weibodemo[962:48379] -[appdelegateapplication:didfinishlaunchingwithoptions:] 2015-04-02 11:37:38.673 weibodemo[962:48379] file:///users/wlsong/library/developer/coresimulator/devices/7dccff56-7a91-4dcc-bb20-ce33fcae42bf/data/containers/data/application/82c32b6f-a842-4bfd-a9df-0126a7c290bc/documents/ 2015-04-02 11:37:38.691 weibodemo[962:48379] managedobjectcontext have created. 2015-04-02 11:37:38.691 weibodemo[962:48379] -[appdelegate setweibostatusesdatabasecontext:] 2015-04-02 11:37:38.695 weibodemo[962:48379] context = < nsmanagedobjectcontext: 0x7b84da00 > 

my questions are:

• why did "context = < nsmanagedobjectcontext: 0x7b84da00 >" appear in last?
• are -[appdelegate application:didfinishlaunchingwithoptions:] , -[mainpagecdtvc awakefromnib] in same thread?
• if run first?

ps: chinese, english poor. forgive me.

the order is:

1. awakefromnib
2. applicationwillfinishlaunching
3. applicationdidfinishlaunching

you don't have worry multi-threading/parallelism here. if follow order see:

1. awakefromnib => defaultcenter observer add => print (null) context
2. applicationdidfinishlaunching => call setter => setter posts notification => print context