objective c - Waiting for code to execute (already used dispatch groups) -


got lengthy section of code shown below , i've hit brick wall. code runs , want do. however, needs finish running code within section before printing "finished" @ end. adding semaphores or dispatch group forces breakpoint. might obvious, give me bit of advice on please?

note: cannot use dispatch @ bottom call method. remember within loop.

for (id in arr) {     searchbyname = nil;     if ([i containsstring:@"word1"] || [i containsstring:@"word2"]) {         nsrange searchfromrange = [i rangeofstring:@"ong>"];         nsrange searchtorange = [i rangeofstring:@"</str"];         nsstring *substring = [i substringwithrange:nsmakerange(searchfromrange.location+searchfromrange.length, searchtorange.location-searchfromrange.location-searchfromrange.length)];         [allergens addobject:substring];         if ([substring isequaltostring:@"examee"] && veg_lac_ovosafe == true) {             veg_ovosafe = false;             vegsafe = false;         }         else if ([substring isequaltostring:@"example"] && veg_lac_ovosafe == true) { //use of heuristics             veg_lacsafe = false;             vegsafe = false;         }         else if ([substring isequaltostring:@"exam"]) {             pescetariansafe = true;             vegsafe = false;             veg_ovosafe = false;             veg_lacsafe = false;             veg_lac_ovosafe = false;             pollotariansafe = false;         }         nscharacterset *characterstoremove = [[nscharacterset alphanumericcharacterset] invertedset];         nscharacterset *numberstoremove = [nscharacterset charactersetwithcharactersinstring:@"0123456789"];         substring = [[substring componentsseparatedbycharactersinset:characterstoremove] componentsjoinedbystring:@""];         searchbyname = [[[substring componentsseparatedbycharactersinset:numberstoremove] componentsjoinedbystring:@""] lowercasestring];     }     else {         nscharacterset *characterstoremove = [[nscharacterset alphanumericcharacterset] invertedset];         nscharacterset *numberstoremove = [nscharacterset charactersetwithcharactersinstring:@"0123456789"];         nsstring *searchitem = [[i componentsseparatedbycharactersinset:characterstoremove] componentsjoinedbystring:@""];         searchbyname = [[[searchitem componentsseparatedbycharactersinset:numberstoremove] componentsjoinedbystring:@""] lowercasestring];     }     if (![searchbyname isequaltostring:@" "]) {         dispatch_queue_t queue = dispatch_get_global_queue(dispatch_queue_priority_high, 0);         dispatch_group_enter(_groupsearch);         dispatch_async(queue, ^{             [[self databasequery:searchbyname] observeeventtype:firdataeventtypechildadded                                                       withblock:^(firdatasnapshot * _nonnull snapshot) {                 if (snapshot.value != null) {                     nslog(@"%@", snapshot.value);                     (int i=0; < [[nsstring stringwithformat:@"%@", snapshot.value] length]; i++) {                         nsstring *x  = [nsstring stringwithformat:@"%c", [[nsstring stringwithformat:@"%@", snapshot.value] characteratindex:i]];                         nslog(@"%@", x);                         if ([x isequaltostring:@"1"]) {                             vegsafe = false;                         }                         else if ([x isequaltostring:@"2"]) {                             vegsafe = false;                             veg_lacsafe = false;                         }                         else if ([x isequaltostring:@"3"]) {                             vegsafe = false;                             veg_ovosafe = false;                         }                         else if ([x isequaltostring:@"4"]) { //could use switch case.                             vegsafe = false;                             veg_lac_ovosafe = false;                             veg_lacsafe = false;                             veg_ovosafe = false;                         }                         else if ([x isequaltostring:@"5"]) {                             pescetariansafe = false;                         }                         else if ([x isequaltostring:@"6"]) {                             pollotariansafe = false;                         }                     }                 }                  dispatch_group_leave(_groupsearch);             }                                                 withcancelblock:^(nserror * _nonnull error) {                 nslog(@"%@", error.localizeddescription);                 dispatch_group_leave(_groupsearch);             }];         });         dispatch_async(dispatch_get_global_queue(dispatch_queue_priority_default, 0), ^{             dispatch_group_wait(_groupsearch, dispatch_time(dispatch_time_now, (int64_t)(2.0 * nsec_per_sec)));             dispatch_sync(queue, ^{                 //hi             });         });     } }  nslog(@"finished");

your use of dispatch_group_wait in wrong place. needs after for loop, not inside it. , can create queue before loop , reuse needed.

dispatch_queue_t queue = dispatch_get_global_queue(dispatch_queue_priority_high, 0);  (id in arr) {     searchbyname = nil;      // lots of other code here      if (![searchbyname isequaltostring:@" "]) {         dispatch_group_enter(_groupsearch);         dispatch_async(queue, ^{             [[self databasequery:searchbyname] observeeventtype:firdataeventtypechildadded withblock:^(firdatasnapshot * _nonnull snapshot) {                 if (snapshot.value != null) {                     nslog(@"%@", snapshot.value);                     (int i=0; < [[nsstring stringwithformat:@"%@", snapshot.value] length]; i++) {                         nsstring *x  = [nsstring stringwithformat:@"%c", [[nsstring stringwithformat:@"%@", snapshot.value] characteratindex:i]];                         nslog(@"%@", x);                         if ([x isequaltostring:@"1"]) {                             vegsafe = false;                         }                         else if ([x isequaltostring:@"2"]) {                             vegsafe = false;                             veg_lacsafe = false;                         }                         else if ([x isequaltostring:@"3"]) {                             vegsafe = false;                             veg_ovosafe = false;                          }                         else if ([x isequaltostring:@"4"]) { //could use switch case.                             vegsafe = false;                             veg_lac_ovosafe = false;                             veg_lacsafe = false;                             veg_ovosafe = false;                         }                         else if ([x isequaltostring:@"5"]) {                             pescetariansafe = false;                         }                         else if ([x isequaltostring:@"6"]) {                             pollotariansafe = false;                         }                     }                 }                 dispatch_group_leave(_groupsearch);             }             withcancelblock:^(nserror * _nonnull error) {                 nslog(@"%@", error.localizeddescription);                 dispatch_group_leave(_groupsearch);             }];          });     } }  dispatch_group_wait(_groupsearch, dispatch_time(dispatch_time_now, (int64_t)(2.0 * nsec_per_sec)));  nslog(@"finished");

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