objective c - iOS 9 - Network reachability change causes the view to freeze - Not a crash -

after upgrading ios 9. app having strange problem.

problem : whenever network reachability changes, app's view freezes. not responding touch events. has not crashed either . checked logs. change network reachability.

more information:

1) if quit app , open again internet online, it's working fine.

2) if open app internet offline, view freezes. doesn't happen in ios 8.4.

i'm using reachability tony million library checking online/offline status.

has faced same issue after upgrading ios 9?

code reference:

self.appisonline = yes; _reachability = [reachability reachabilitywithhostname:@"www.google.com"];  __weak __typeof(self)weakself = self; [_reachability setreachableblock: ^(reachability * reachability) {      nslog(@"online");      if (!weakself.appisonline)     {         weakself.appisonline = yes;         weakself.willshowalertview = yes;         dispatch_async(dispatch_get_main_queue(), ^{             customalertview *alertview = [[customalertview alloc] initwithtitle:@"warning" andmessage:@"the internet connection appears online. app switch online mode now" delegate:weakself withbuttons:@[@"ok"]];             alertview.shouldtapoutsidetoclose = yes;             [alertview showinview:main_window];         });     } }]; [_reachability setunreachableblock:^(reachability * reachability) {      nslog(@"offline");      if (weakself.appisonline)     {         [[nsnotificationcenter defaultcenter] postnotificationname:offline_state_notification object:nil];         weakself.appisonline = no;         dispatch_async(dispatch_get_main_queue(), ^{             [[apputilities sharedutilities] displayalertviewwithtitle:@"warning" andmessage:@"the internet connection appears offline. app switch offline mode now"];         });     } }];  [_reachability startnotifier]; 

looks main ui thread being blocked , trigger turning off wi-fi. thread trace below.

thread 1queue : com.apple.main-thread (serial)  #0  0x38739130 in mach_msg_trap () #1  0x38738f30 in mach_msg () #2  0x265624ec in __cfrunloopservicemachport () #3  0x26560872 in __cfrunlooprun () #4  0x264b31e8 in cfrunlooprunspecific () #5  0x264b2fdc in cfrunloopruninmode () #6  0x2f757af8 in gseventrunmodal () #7  0x2a71818c in uiapplicationmain () #8  0x00117f20 in main  thread 3queue : com.apple.libdispatch-manager (serial)  #0  0x3874e3c0 in kevent_qos () #1  0x0067d5f6 in _dispatch_mgr_invoke () #2  0x0066ea76 in _dispatch_mgr_thread ()  com.apple.nsurlconnectionloader (11)  #0  0x38739130 in mach_msg_trap () #1  0x38738f30 in mach_msg () #2  0x265624ec in __cfrunloopservicemachport () #3  0x26560872 in __cfrunlooprun () #4  0x264b31e8 in cfrunlooprunspecific () #5  0x264b2fdc in cfrunloopruninmode () #6  0x25e240ae in +[nsurlconnection(loader) _resourceloadloop:] () #7  0x273747fc in __nsthread__start__ () #8  0x387ebc92 in _pthread_body () #9  0x387ebc06 in _pthread_start () #10 0x387e9a24 in thread_start ()  afnetworking (12)#0 0x38739130 in mach_msg_trap ()  #1  0x38738f30 in mach_msg () #2  0x265624ec in __cfrunloopservicemachport () #3  0x26560872 in __cfrunlooprun () #4  0x264b31e8 in cfrunlooprunspecific () #5  0x264b2fdc in cfrunloopruninmode () #6  0x272a3d7c in -[nsrunloop(nsrunloop) runmode:beforedate:] () #7  0x272f28ec in -[nsrunloop(nsrunloop) run] () #8  0x00122a2e in +[afurlconnectionoperation networkrequestthreadentrypoint:] @ /pods/afnetworking/afnetworking/afurlconnectionoperation.m:168 #9  0x273747fc in __nsthread__start__ () #10 0x387ebc92 in _pthread_body () #11 0x387ebc06 in _pthread_start () #12 0x387e9a24 in thread_start ()  com.apple.cfsocket.private (13)#0   0x3874cfb4 in __select ()  #1  0x26567990 in __cfsocketmanager () #2  0x387ebc92 in _pthread_body () #3  0x387ebc06 in _pthread_start () #4  0x387e9a24 in thread_start () 

i able find real issue. not reachability class. due customalertview. whenever reachability changes, app pops alert saying offline/online. presenting alert view directly on main window

[alertview showinview:main_window]; 

where

#define main_window         [uiapplication sharedapplication].keywindow 

in ios 9 not allowed. when tries show, ui thread paused. solved doing instead

[alertview showinview:main_window.rootviewcontroller.view];