I am reading an XML file that basically looks as follows:\[code\]<teams> <team id = "A1"> <player>Tom</player> <player>Dick</player> <player>Harry</player> </team> <team id = "A2"> <player>John</player> <player>Tom</player> </team></teams>\[/code\]I use NSXMLParser and create Core Data entities in the \[code\]didEndElement\[/code\] delegate method as follows:\[code\]if ([elementName isEqualToString
"player"]) { if ([nodeContent length] != 0) { player = [NSEntityDescription insertNewObjectForEntityForName"Player" inManagedObjectContext:savedContext]; player.name = nodeContent; }}\[/code\]And do something similar for 'team' on \[code\]didStartElement\[/code\]. '\[code\]nodeContent\[/code\]' is what I get from \[code\]foundCharacters\[/code\]. So far so good. Everything works ok. However, in this example, I have a player (Tom) who plays in two teams. This is possible but I do not want two entities of Tom in my Core Data. So, I check whether a player with that name already exists:\[code\] Player *player = nil; NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName"Player"]; request.predicate = [NSPredicate predicateWithFormat"name = %@", nodeContent]; NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey"name" ascending:YES]; request.sortDescriptors = [NSArray arrayWithObject:sortDescriptor]; NSError *error = nil; NSArray *players = [savedContext executeFetchRequest:request error:&error]; if (!players || ([players count] > 1)) { NSLog(@"WTF?!"); } else if ([players count] == 0) { player = [NSEntityDescription insertNewObjectForEntityForName"Player" inManagedObjectContext:savedContext]; player.name = nodeContent; } else { player = [players lastObject]; } [player addPlaysInTeamObject:team];\[/code\]... and if that is the case, I just use that entity. If not, I create a new one as before.Now, this all works when I run the parsing synchronously in the foreground, but I do not want to freeze my app while it is downloading stuff. So I put all this in a thread. It sometimes works ok, but occasionally I get the following error on the \[code\]executeFetchRequest\[/code\]:\[code\]*** Terminating app due to uncaught exception 'NSGenericException', reason: '*** Collection <__NSCFSet: 0x8177a90> was mutated while being enumerated.'*** First throw call stack
0x12d3022 0x1784cd6 0x12d2bf1 0x41314 0xd5b9 0xceaa25 0x19118f6 0x191dab0 0xce901d 0xcf8d 0xc3a5 0x1f31330 0x1f32439 0x908b9b24 0x908bb6fe)terminate called throwing an exception(lldb)\[/code\]It happens sometimes when I don't use the (foreground) UI, but always when I do touch any UI element, even if that UI element does not use the data that I am loading in the background. I checked this forum and concluded that it might be caused by the parser filling up the database while at the same time the \[code\]NSFetchRequest\[/code\] uses the database to search for a certain name. (Although I do not really understand that because all this happens in the same thread.) Is there anyone who can tell me what I am doing wrong?Thank you!--GB
"player"]) { if ([nodeContent length] != 0) { player = [NSEntityDescription insertNewObjectForEntityForName"Player" inManagedObjectContext:savedContext]; player.name = nodeContent; }}\[/code\]And do something similar for 'team' on \[code\]didStartElement\[/code\]. '\[code\]nodeContent\[/code\]' is what I get from \[code\]foundCharacters\[/code\]. So far so good. Everything works ok. However, in this example, I have a player (Tom) who plays in two teams. This is possible but I do not want two entities of Tom in my Core Data. So, I check whether a player with that name already exists:\[code\] Player *player = nil; NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName"Player"]; request.predicate = [NSPredicate predicateWithFormat"name = %@", nodeContent]; NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey"name" ascending:YES]; request.sortDescriptors = [NSArray arrayWithObject:sortDescriptor]; NSError *error = nil; NSArray *players = [savedContext executeFetchRequest:request error:&error]; if (!players || ([players count] > 1)) { NSLog(@"WTF?!"); } else if ([players count] == 0) { player = [NSEntityDescription insertNewObjectForEntityForName"Player" inManagedObjectContext:savedContext]; player.name = nodeContent; } else { player = [players lastObject]; } [player addPlaysInTeamObject:team];\[/code\]... and if that is the case, I just use that entity. If not, I create a new one as before.Now, this all works when I run the parsing synchronously in the foreground, but I do not want to freeze my app while it is downloading stuff. So I put all this in a thread. It sometimes works ok, but occasionally I get the following error on the \[code\]executeFetchRequest\[/code\]:\[code\]*** Terminating app due to uncaught exception 'NSGenericException', reason: '*** Collection <__NSCFSet: 0x8177a90> was mutated while being enumerated.'*** First throw call stack0x12d3022 0x1784cd6 0x12d2bf1 0x41314 0xd5b9 0xceaa25 0x19118f6 0x191dab0 0xce901d 0xcf8d 0xc3a5 0x1f31330 0x1f32439 0x908b9b24 0x908bb6fe)terminate called throwing an exception(lldb)\[/code\]It happens sometimes when I don't use the (foreground) UI, but always when I do touch any UI element, even if that UI element does not use the data that I am loading in the background. I checked this forum and concluded that it might be caused by the parser filling up the database while at the same time the \[code\]NSFetchRequest\[/code\] uses the database to search for a certain name. (Although I do not really understand that because all this happens in the same thread.) Is there anyone who can tell me what I am doing wrong?Thank you!--GB