NSFetchedResultsController initWithFetchRequest引发EXE-BAD-ACCESS异常

-[NSEntityDescription subentitiesByName]: message sent to deallocated instance 0x8b09c80任何帮助将不胜感激.这是我对结果控制器的了解:- (NSFetchedResultsController*)eventsResultsController { if (eventsResultsController_ == nil) { NSFetchRequest *aFetchRequest = [[PADataContext sharedInstance] makeGetAllFetchRequestForEntity:@"PAEvent" sortedBy:@"when" ascending:NO]; // NOTE: crashes on this next line NSFetchedResultsController *aFetchedResultsContorller = [[NSFetchedResultsController alloc] initWithFetchRequest:aFetchRequest managedObjectContext:[[PADataContext sharedInstance] managedObjectContext] sectionNameKeyPath:@"whenMonth" cacheName:@"AllEvent"]; self.eventsResultsController = aFetchedResultsContorller; [aFetchedResultsContorller release]; } return eventsResultsController_;}这是我用来创建NSFetchRequest的代码:- (NSFetchRequest*)makeGetAllFetchRequestForEntity:(NSString*)entityName sortedBy:(NSString*)sortString ascending:(BOOL)ascending { NSFetchRequest *fetchRequest = [[[NSFetchRequest alloc] init] autorelease]; NSEntityDescription *entity = [NSEntityDescription entityForName:entityName inManagedObjectContext:[self managedObjectContext]]; [fetchRequest setEntity:entity]; if (sortString != nil) { // add sorting information NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:sortString ascending:ascending]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [fetchRequest setSortDescriptors:sortDescriptors]; [sortDescriptors release]; [sortDescriptor release]; } [entity release]; return fetchRequest;}上下文对象仅创建一次，并在应用程序的整个生命周期中保持为单一状态.我已经检查了确保在视图控制器被dealloc编辑时释放eventsResultsController_.在堆栈中，我被告知它在initWithFetchRequest:managedObjectContext:sectionNameKeyPath:cacheName方法中崩溃了:#0 0x00f04057 in ___forwarding___#1 0x00f03f22 in __forwarding_prep_0___#2 0x00da1b4d in -[NSFetchedResultsController initWithFetchRequest:managedObjectContext:sectionNameKeyPath:cacheName:]#3 0x00008c94 in -[PAHistoryListTableView eventsResultsController] at PAHistoryListTableView.m:125#4 0x00008a5b in -[PAHistoryListTableView loadData] at PAHistoryListTableView.m:52#5 0x00008a2a in -[PAHistoryListTableView viewDidLoad] at PAHistoryListTableView.m:43...解决方案您使用非保留呼叫创建了实体:NSEntityDescription *entity = [NSEntityDescription entityForName:entityName inManagedObjectContext:[self managedObjectContext]];然后您将其释放:[entity release];取出发行版.当您关注NSEntityDescription被过度发布的事实时，这很容易找到.您只在一个地方使用它，因此很容易发现错误.I have an NSFetchedResultsController inside a subclass of UITableViewController inside a UINavigationController. When I run the app, everything works perfectly the first three times I access the view (going to it, then clicking 'Back', then going to it again), but on the fourth (always) it crashes with the following:-[NSEntityDescription subentitiesByName]: message sent to deallocated instance 0x8b09c80Any help would be much appreciated.Here is my getter for the results controller:- (NSFetchedResultsController*)eventsResultsController { if (eventsResultsController_ == nil) { NSFetchRequest *aFetchRequest = [[PADataContext sharedInstance] makeGetAllFetchRequestForEntity:@"PAEvent" sortedBy:@"when" ascending:NO]; // NOTE: crashes on this next line NSFetchedResultsController *aFetchedResultsContorller = [[NSFetchedResultsController alloc] initWithFetchRequest:aFetchRequest managedObjectContext:[[PADataContext sharedInstance] managedObjectContext] sectionNameKeyPath:@"whenMonth" cacheName:@"AllEvent"]; self.eventsResultsController = aFetchedResultsContorller; [aFetchedResultsContorller release]; } return eventsResultsController_;}This is the code I use to create my NSFetchRequest:- (NSFetchRequest*)makeGetAllFetchRequestForEntity:(NSString*)entityName sortedBy:(NSString*)sortString ascending:(BOOL)ascending { NSFetchRequest *fetchRequest = [[[NSFetchRequest alloc] init] autorelease]; NSEntityDescription *entity = [NSEntityDescription entityForName:entityName inManagedObjectContext:[self managedObjectContext]]; [fetchRequest setEntity:entity]; if (sortString != nil) { // add sorting information NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:sortString ascending:ascending]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [fetchRequest setSortDescriptors:sortDescriptors]; [sortDescriptors release]; [sortDescriptor release]; } [entity release]; return fetchRequest;}The context object is created once and held throughout the lifetime of the app in a singleton.I have checked the ensure the eventsResultsController_ gets released when the view controller gets dealloced.In the stack, I'm told it crashed in the initWithFetchRequest:managedObjectContext:sectionNameKeyPath:cacheName method:#0 0x00f04057 in ___forwarding___#1 0x00f03f22 in __forwarding_prep_0___#2 0x00da1b4d in -[NSFetchedResultsController initWithFetchRequest:managedObjectContext:sectionNameKeyPath:cacheName:]#3 0x00008c94 in -[PAHistoryListTableView eventsResultsController] at PAHistoryListTableView.m:125#4 0x00008a5b in -[PAHistoryListTableView loadData] at PAHistoryListTableView.m:52#5 0x00008a2a in -[PAHistoryListTableView viewDidLoad] at PAHistoryListTableView.m:43... 解决方案 You created your entity with a non-retaining call:NSEntityDescription *entity = [NSEntityDescription entityForName:entityName inManagedObjectContext:[self managedObjectContext]];And then you released it:[entity release];Take out the release. This is trivial to find when you focus on the fact that it was the NSEntityDescription that was over-released. You only use that in one place, so it's easy to find the mistake. 这篇关于NSFetchedResultsController initWithFetchRequest引发EXE-BAD-ACCESS异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！