Hi,
I've attempted to add the TopSongs parser and Core Data files into my application, and it now builds succesfully, with no errors or warning messages. However, as soon as the app loads, it crashes, giving the following reason:
UPDATE: I've got it all working, but my TableView doesn't show any data, and the app doesn't respond to the following breakpoints.
Thanks.
UPDATE: Here's the new code that doesn't respond to the breakpoints.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)table {
return [[fetchedResultsController sections] count];
}
- (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section {
id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
return [sectionInfo numberOfObjects];
}
- (void)viewDidUnload {
[super viewDidUnload];
self.tableView = nil;
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSManagedObjectContextDidSaveNotification object:self.managedObjectContext];
[self.tableView reloadData];
}
- (UITableViewCell *)tableView:(UITableView *)table cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *kCellIdentifier = @"SongCell";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:kCellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:kCellIdentifier] autorelease];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
cell.textLabel.font = [UIFont boldSystemFontOfSize:14];
}
Incident *incident = [fetchedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text = [NSString stringWithFormat:NSLocalizedString(@"#%d %@", @"#%d %@"), incident.title];
return cell;
}
- (void)tableView:(UITableView *)table didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[table deselectRowAtIndexPath:indexPath animated:YES];
self.detailController.incident = [fetchedResultsController objectAtIndexPath:indexPath];
[self.navigationController pushViewController:self.detailController animated:YES];
}
UPDATE: Here's the code where all instances of fetch are found.
- (Category *)categoryWithName:(NSString *)name {
NSTimeInterval before = [NSDate timeIntervalSinceReferenceDate];
#ifdef USE_CACHING
// check cache
CacheNode *cacheNode = [cache objectForKey:name];
if (cacheNode != nil) {
// cache hit, update access counter
cacheNode.accessCounter = accessCounter++;
Category *category = (Category *)[managedObjectContext objectWithID:cacheNode.objectID];
totalCacheHitCost += ([NSDate timeIntervalSinceReferenceDate] - before);
cacheHitCount++;
return category;
}
#endif
// cache missed, fetch from store - if not found in store there is no category object for the name and we must create one
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:self.categoryEntityDescription];
NSPredicate *predicate = [self.categoryNamePredicateTemplate predicateWithSubstitutionVariables:[NSDictionary dictionaryWithObject:name forKey:kCategoryNameSubstitutionVariable]];
[fetchRequest setPredicate:predicate];
NSError *error = nil;
NSArray *fetchResults = [managedObjectContext executeFetchRequest:fetchRequest error:&error];
[fetchRequest release];
NSAssert1(fetchResults != nil, @"Unhandled error executing fetch request in import thread: %@", [error localizedDescription]);
Category *category = nil;
if ([fetchResults count] > 0) {
// get category from fetch
category = [fetchResults objectAtIndex:0];
} else if ([fetchResults count] == 0) {
// category not in store, must create a new category object
category = [[Category alloc] initWithEntity:self.categoryEntityDescription insertIntoManagedObjectContext:managedObjectContext];
category.name = name;
[category autorelease];
}
#ifdef USE_CACHING
// add to cache
// first check to see if cache is full
if ([cache count] >= cacheSize) {
// evict least recently used (LRU) item from cache
NSUInteger oldestAccessCount = UINT_MAX;
NSString *key = nil, *keyOfOldestCacheNode = nil;
for (key in cache) {
CacheNode *tmpNode = [cache objectForKey:key];
if (tmpNode.accessCounter < oldestAccessCount) {
oldestAccessCount = tmpNode.accessCounter;
[keyOfOldestCacheNode release];
keyOfOldestCacheNode = [key retain];
}
}
// retain the cache node for reuse
cacheNode = [[cache objectForKey:keyOfOldestCacheNode] retain];
// remove from the cache
[cache removeObjectForKey:keyOfOldestCacheNode];
} else {
// create a new cache node
cacheNode = [[CacheNode alloc] init];
}
cacheNode.objectID = [category objectID];
cacheNode.accessCounter = accessCounter++;
[cache setObject:cacheNode forKey:name];
[cacheNode release];
#endif
totalCacheMissCost += ([NSDate timeIntervalSinceReferenceDate] - before);
cacheMissCount++;
return category;
}
And this one...
- (void)fetch {
NSError *error = nil;
BOOL success = [self.fetchedResultsController performFetch:&error];
NSAssert2(success, @"Unhandled error performing fetch at SongsViewController.m, line %d: %@", __LINE__, [error localizedDescription]);
[self.tableView reloadData];
}
- (NSFetchedResultsController *)fetchedResultsController {
if (fetchedResultsController == nil) {
NSFetchRequest *fetchRequest = [[[NSFetchRequest alloc] init] autorelease];
[fetchRequest setEntity:[NSEntityDescription entityForName:@"Song" inManagedObjectContext:managedObjectContext]];
NSArray *sortDescriptors = nil;
NSString *sectionNameKeyPath = nil;
if ([fetchSectioningControl selectedSegmentIndex] == 1) {
sortDescriptors = [NSArray arrayWithObjects:[[[NSSortDescriptor alloc] initWithKey:@"category.name" ascending:YES] autorelease], [[[NSSortDescriptor alloc] initWithKey:@"rank" ascending:YES] autorelease], nil];
sectionNameKeyPath = @"category.name";
} else {
sortDescriptors = [NSArray arrayWithObject:[[[NSSortDescriptor alloc] initWithKey:@"rank" ascending:YES] autorelease]];
}
[fetchRequest setSortDescriptors:sortDescriptors];
fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:sectionNameKeyPath cacheName:@"SongsCache"];
}
return fetchedResultsController;
}