ios - how to alter NSMutableArray in an specific array -

i have nsmutablearray wich holds custom class of mkmapkit.

mappoint *placeobject = [[mappoint alloc] initwithtitle:title subtitle:subtitle coordinate:loc description:description storeimage:storeimage]; [annotationarray addobject:placeobject]; 

my routine fills placeobject without image because load asynchronously , finished after couple of seconds. questions is: there way alter placeobject within annotationarray?

edit

to display issue in better way here code parts:

if (annotationarray == nil) {     [self setannotationarray:[[nsmutablearray alloc] init]]; } (nsdictionary *locationdetails in parser.items) {     __block nsdata *storeimagedata;     dispatch_queue_t queue = dispatch_get_global_queue(dispatch_queue_priority_high, 0);     dispatch_async(queue, ^{         storeimagedata = [nsdata datawithcontentsofurl:storeimageurl];          dispatch_sync(dispatch_get_main_queue(), ^{             uiimage *storeimagetmp = [uiimage imagewithdata:storeimagedata];             counterblock ++;             nslog(@"async: %d", counterblock);             [imagearray addobject:storeimagetmp];             });         }); mappoint *placeobject = [[mappoint alloc] initwithtitle:title subtitle:subtitle coordinate:loc description:description storeimage:storeimage]; [annotationarray addobject:placeobject]; } [mapview addannotations:annotationarray]; 

after done: dispatch_queue_t start working. check every 2 seconds if loaded. start alter annotationarray , refresh annotations (remove -> add map witch additional image)

- (void) checkmap {     if (counterblock == 547)     {         (int i=0; i<=counterblock; i++)         {             mappoint *point = annotationarray[i];             point.storeimage = imagearray[i];         }         if(timer)         {             [timer invalidate];             timer = nil;         }         [mapview removeannotations:mapview.annotations];         [mapview addannotations:annotationarray];     } } 

all need reference 1 of mappoint objects in array. can set properties and/or call methods on object needed.

mappoint *point = annotationarray[x]; // x whatever index need point.image = ... // image