我的viewController中有标准的fetchedResultsController方法和委托方法，但它们没有被调用。我通过在这个方法中放入NSLog来测试这一点，控制台从未显示过这一点。
我确保将FetchedResultsController委托添加到.h和.m.
有什么想法吗？
接口
@interface LogViewController : UIViewController <NSFetchedResultsControllerDelegate, UITableViewDelegate, UITableViewDataSource>
@property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController;
@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
@property (nonatomic, retain) NSArray *logArray;
@property (nonatomic, retain) UIImageView *imageView;
@property (nonatomic, retain) Session *session;
@property (nonatomic, retain) IBOutlet UITableView *logTableView;
@end
实施
#import "LogViewController.h"
@implementation LogViewController
@synthesize fetchedResultsController = __fetchedResultsController;
@synthesize managedObjectContext;
@synthesize logArray;
@synthesize logTableView;
@synthesize imageView;
@synthesize session;
- (void)dealloc
{
[logArray release];
[logTableView release];
[session release];
[__fetchedResultsController release];
[managedObjectContext release];
[super dealloc];
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationItem.title = @"Log";
logTableView.backgroundColor = [UIColor clearColor];
logTableView.separatorColor = [UIColor blackColor];
self.navigationController.navigationBar.tintColor = [UIColor colorWithRed:24/255.0 green:83/255.0 blue:170/255.0 alpha:1.0];
self.logArray = [[NSArray alloc]initWithObjects:@"Today's Workout", @"Last Workout", @"Past Week", @"Past Month", @"All Workouts", nil];
if (managedObjectContext == nil)
{
self.managedObjectContext = [(CurlAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
}
}
- (void)viewDidUnload
{
self.logArray = nil;
self.logTableView = nil;
[super viewDidUnload];
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [self.logArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
TDBadgedCell *cell = [[[TDBadgedCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier] autorelease];
}
cell.textLabel.textColor = [UIColor blackColor];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
cell.textLabel.text = [logArray objectAtIndex:indexPath.row];
cell.backgroundColor = [UIColor clearColor];
UIImageView *myImageView = nil;
if (indexPath.row == 0)
{
myImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"customcell_background_top.png"]];
}
else if (indexPath.row == 4)
{
myImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"customcell_background_bottom.png"]];
}
else
{
myImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"customcell_background_middle.png"]];
}
[cell setBackgroundView:myImageView];
[myImageView release];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"MMM d, y"];
NSDate *date = nil;
if (indexPath.row == 0)
{
date = [NSDate date];
NSString *dateString = [dateFormatter stringFromDate:date];
cell.badgeString = dateString;
}
else if (indexPath.row == 1)
{
self.session = [[__fetchedResultsController fetchedObjects]lastObject];
NSDate *date = self.session.timeStamp;
NSString *dateString = [dateFormatter stringFromDate:date];
cell.badgeString = dateString;
}
else if (indexPath.row > 1)
{
cell.badgeString = [NSString stringWithFormat:@"%i", [[__fetchedResultsController fetchedObjects]count]];
}
cell.badgeColor = [UIColor colorWithRed:24/255.0 green:83/255.0 blue:170/255.0 alpha:1.0];
[dateFormatter release];
return cell;
}
-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
// [cell setBackgroundColor:[UIColor colorWithRed:209/255.0 green:209/255.0 blue:209/255.0 alpha:1.0]];
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
if (indexPath.row == 0 || indexPath.row == 1)
{
SessionViewController *detailViewController = [[SessionViewController alloc] initWithNibName:@"SessionViewController" bundle:nil];
detailViewController.title = [logArray objectAtIndex: indexPath.row];
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController release];
}
else
{
LogResultsViewController *detailViewController = [[LogResultsViewController alloc] initWithNibName:@"LogResultsTableViewController" bundle:nil];
detailViewController.title = [logArray objectAtIndex: indexPath.row];
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController release];
}
}
#pragma mark - Fetched results controller
- (NSFetchedResultsController *)fetchedResultsController
{
if (__fetchedResultsController != nil)
{
return __fetchedResultsController;
}
// Create the fetch request for the entity.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Session" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
[aFetchedResultsController release];
[fetchRequest release];
[sortDescriptor release];
[sortDescriptors release];
NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error])
{
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
*/
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return __fetchedResultsController;
NSLog(@"Number of Objects = %i",
[[__fetchedResultsController fetchedObjects] count]);
}
#pragma mark - Fetched results controller delegate
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
[self.logTableView beginUpdates];
}
- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
switch(type)
{
case NSFetchedResultsChangeInsert:
[self.logTableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[self.logTableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
newIndexPath:(NSIndexPath *)newIndexPath
{
UITableView *tableView = self.logTableView;
switch(type)
{
case NSFetchedResultsChangeInsert:
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeUpdate:
[self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
break;
case NSFetchedResultsChangeMove:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
[self.logTableView endUpdates];
}
@end
替换类似的调用
self.session = [[__fetchedResultsController fetchedObjects]lastObject];
用这个
self.session = [[self.fetchedResultsController fetchedObjects]lastObject];
I。E.使用延迟加载NSFetchedResultsController的getter
如果使用延迟加载，则必须使用getter，因为如果从不调用创建对象的getter，则实例变量将保持为零。