ios - How to observe the dealloc process -

in app i'm downloading location data , showing them on map. there scenarios cannot understand why happening. sometimes, mapview(google map) class dealloc getting called , i'm unable see markers on map(i can still see current location).

this how mapview setup in storyboard:

 [containervc] -embedsegue->[mapview] 

container vc root vc.

and in rootvc class:

   @property (weak, nonatomic) mapvc *mapvc;     - (void)prepareforsegue:(uistoryboardsegue *)segue sender:(id)sender{     if ([[segue identifier] isequaltostring: @"embeddedmapvc"]) {         self.mapvc = [segue destinationviewcontroller];         self.mapvc.delegate = self;     }   } 

and in mapvc class(all properties strong,nonatomic):

  -(void)viewdidappear:(bool)animated{        [super viewdidappear:animated];        [self setupmapview];   }  - (void)setupmapview{      mylog(@"map view refreshed/setup");     //set map view     self.infowindow = [[mymapinfowindow alloc] initwithframe:cgrectmake(0, 0, 210, 47)];     self.infowindow.delegate = self;       cllocation *center = [[mylocationmonitor sharedinstance] getlocation];      gmscameraposition *camera = [gmscameraposition camerawithlatitude:center.coordinate.latitude longitude:center.coordinate.longitude zoom:18];      self.mapview = [gmsmapview mapwithframe:cgrectzero camera:camera];     self.mapview.camera=camera;     [self.mapview setmaptype:kgmstypenormal];     [self.mapview setminzoom:14 maxzoom:18];     [self.mapview setdelegate:self];     self.mapview.mylocationenabled=yes;     self.mapview.settings.rotategestures = no;     self.mapview.settings.mylocationbutton = yes;     [self.mapview setpadding:uiedgeinsetsmake(0, 0, 62, 0)];      self.view = self.mapview;     [self setupmarkers];  }  - (void)setupmarkers{  mylog(@"setting markers");  self.annotations = nil;  [self.mapview clear];   [[mylocationmonitor sharedinstance] getbuildingswithcompletion:^(bool success, nsarray *buildings) {      self.buildings = buildings;      mylog(@"_buildings_: %@", self.buildings);      if (success) {           gmscoordinatebounds  *bounds =  [[gmscoordinatebounds alloc] init];           self.annotations = [[nsmutablearray alloc] init];           (nsdictionary *location in buildings) {               cllocationcoordinate2d coordinate = cllocationcoordinate2dmake([[location objectforkey:@"latitude"] doublevalue], [[location objectforkey:@"longitude"] doublevalue]);               bounds = [bounds includingcoordinate:coordinate];               gmsmarker *marker = [gmsmarker markerwithposition:coordinate];              marker.title = [location objectforkey:@"name"];              marker.map = self.mapview;              marker.icon = [uiimage imagenamed:@"boost-buildingmarkericon"];              marker.userdata = @{@"building":location};              marker.infowindowanchor = cgpointmake(1.0f, -0.1f);              marker.opacity = 1.0;               [self.annotations addobject:marker];          }          [self.mapview animatewithcameraupdate:[gmscameraupdate fitbounds:bounds withpadding:50.0]];       }   }];  }   -(void)dealloc{   mylog(@"mapvc dealloc called");  } 

so, rootvc move controller , after finish network call comeback rootvc, prepareforsegue gets triggered , call goes mapvc class, , setups mapview(in process mapvc dealloc gets called in case, i'm unable see markers on map).

i couldn't info stacktrace. know why mapvc getting deallocated ? how make sure mapvc not deallocated @ time ?

edit:

i logged mapvc self in dealloc case:

 <mapvc: 0x7ff83f2883c0> on didappear  <mapvc: 0x7ff83f2883c0> on dealloc (why happening ?)  <mapvc: 0x7ff84475b6f0> new instance again on viewdidappear 

how make sure mapvc not deallocated @ time ?

if require vc exist @ time when not onscreen (or @ least in navigation stack), have broken mvc. don't think that's quite what's happening here, it's important keep in mind. network operations should happen in model layer, , view layer should observe model. view controllers responsible managing views visible, not network operations. have organized view controllers incorrectly.

that said, isn't actual problem in case. problem nothing retaining mapvc. it's weak in root view controller it's being released segue complete (the segue retains while running). if mapvc embedded in root view controller, should strong.