我有一些“详细信息”保存到我的核心数据中，并且我试图将其从NSFetchedResultsController调用到tableView中。无论出于什么原因，一旦块运行完毕，就不会填充tableView。
我一直在寻找并要求我在任何地方都可以尝试找出整个核心数据崩溃的原因。希望这里有人能帮助我!
HomeViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationItem.title = @"Home";
self.navigationController.navigationBar.tintColor = [UIColor colorWithRed:0 green:0.7 blue:2.3 alpha:1];
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCompose target:self action:@selector(addShindy:)];
self.tableView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"light_alu.png"]];
self.tableView.opaque = NO;
self.tableView.backgroundView = nil;
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:@selector(refresh:)
forControlEvents:UIControlEventValueChanged];
self.refreshControl = refreshControl;
[self setShindyDatabase:self.shindyDatabase];
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
if (!self.shindyDatabase) {
NSURL *url = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
self.shindyDatabase = [[UIManagedDocument alloc] initWithFileURL:url];
}
}
- (void)refresh:(UIRefreshControl *)sender
{
[self useDocument];
[sender endRefreshing];
}
- (void)addShindy:(UIBarButtonItem *)sender
{
AddShindyViewController *addShindyViewController = [[AddShindyViewController alloc] initWithNibName:@"AddShindyViewController" bundle:nil];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:addShindyViewController];
[self presentViewController:navController animated:YES completion:nil];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma Core Date Stack
- (void)fetchShindyDataIntoDocument:(UIManagedDocument *)document
{
dispatch_queue_t fetchIntoDocument = dispatch_queue_create("Fetch Into Document", nil);
dispatch_async(fetchIntoDocument, ^{
NSArray *shindys = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
for (NSDictionary *shindyInfo in shindys) {
[Shindy shindyWithShindyDBInfo:shindyInfo inManagedObjectContext:document.managedObjectContext];
}
[document saveToURL:document.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:NULL];
});
}
- (void)setShindyDatabase:(UIManagedDocument *)shindyDatabase
{
if (_shindyDatabase != shindyDatabase) {
_shindyDatabase = shindyDatabase;
[self useDocument];
}
}
- (void)useDocument
{
NSError *error = nil;
if (![[NSFileManager defaultManager] fileExistsAtPath:[self.shindyDatabase.fileURL path]]) {
NSLog(@"Create document");
[self.shindyDatabase saveToURL:self.shindyDatabase.fileURL forSaveOperation:UIDocumentSaveForCreating completionHandler:^(BOOL success) {
[self setupFetchedResultsController];
[self fetchShindyDataIntoDocument:self.shindyDatabase];
if (!success) {
NSLog(@"error for creation of document: %@", [error localizedDescription]);
}
}];
} else if (self.shindyDatabase.documentState == UIDocumentStateClosed) {
NSLog(@"Closed document");
[self.shindyDatabase.managedObjectContext.parentContext performBlock:^{
[self setupFetchedResultsController];
}];
} else if (self.shindyDatabase.documentState == UIDocumentStateNormal) {
NSLog(@"Normal Document");
[self setupFetchedResultsController];
}
if (error) {
NSLog(@"Error in useDocument: %@", [error localizedDescription]);
}
}
- (void)setupFetchedResultsController
{
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Shindy"];
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"details" ascending:YES];
request.sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
// request.predicate = [NSPredicate predicateWithFormat:@"details = %@", [self.shindyDatabase valueForKey:@"details"]];
self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:request
managedObjectContext:self.shindyDatabase.managedObjectContext
sectionNameKeyPath:nil
cacheName:nil];
}
#pragma mark - Table view data source
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 75;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"Cell"];
}
Shindy *shindy = [self.fetchedResultsController objectAtIndexPath:indexPath];
NSLog(@"%@", shindy.details);
cell.textLabel.text = shindy.details;
Shindy + CreateDB.m
+ (Shindy *)shindyWithShindyDBInfo:(NSDictionary *)shindyInfo
inManagedObjectContext:(NSManagedObjectContext *)context
{
Shindy *shindy = nil;
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Shindy"];
// NSSortDescriptor *dateAndTimeSort = [NSSortDescriptor sortDescriptorWithKey:@"dateAndTime" ascending:YES];
NSSortDescriptor *detailsSort = [NSSortDescriptor sortDescriptorWithKey:@"details" ascending:YES];
// NSSortDescriptor *locationSort = [NSSortDescriptor sortDescriptorWithKey:@"location" ascending:YES];
// NSSortDescriptor *nameSort = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];
// NSSortDescriptor *photoSort = [NSSortDescriptor sortDescriptorWithKey:@"photo" ascending:YES];
// NSSortDescriptor *timePostedSort = [NSSortDescriptor sortDescriptorWithKey:@"timePosted" ascending:YES];
// title
request.sortDescriptors = [NSArray arrayWithObject:detailsSort];
// request.sortDescriptors = [NSArray arrayWithObjects:dateAndTimeSort, detailsSort, locationSort, nameSort, photoSort, timePostedSort, nil];
NSError *error = nil;
NSArray *matches = [context executeFetchRequest:request error:&error];
if (error) {
NSLog(@"document failed in file: %@", [error localizedDescription]);
}
if (!matches || ([matches count] > 1)) {
NSError *error = nil;
NSLog(@"error in DBInfo: %@", [error localizedDescription]);
} else if ([matches count] == 0) {
shindy = [NSEntityDescription insertNewObjectForEntityForName:@"Shindy" inManagedObjectContext:context];
// shindy.dateAndTime = [shindyInfo objectForKey:@"dateAndTime"];
shindy.details = [shindyInfo objectForKey:@"details"];
// shindy.location = [shindyInfo objectForKey:@"location"];
// shindy.name = [shindyInfo objectForKey:@"name"];
// shindy.photo = [shindyInfo objectForKey:@"photo"];
// shindy.timePosted = [shindyInfo objectForKey:@"timePosted"];
// title
// Guestlist? The rest?
// Use below for reference
// shindy.whoseShindy = [User userWithName:[shindyInfo objectForKey:@"whoseShindy"] inManagedObjectContext:context];
} else {
shindy = [matches lastObject];
}
return shindy;
}
编辑:
我想我还应该显示一个文件，该文件已被设置为
HomeViewController的子类。与您粘贴在Apple文档中的代码基本相同CoreDataTableViewController.h
#import <UIKit/UIKit.h>
#import <CoreData/CoreData.h>
@interface CoreDataTableViewController : UITableViewController <NSFetchedResultsControllerDelegate>
@property (strong, nonatomic) NSFetchedResultsController *fetchedResultsController;
- (void)performFetch;
@property (nonatomic) BOOL suspendAutomaticTrackingOfChangesInManagedObjectContext;
@property BOOL debug;
@end
CoreDataTableViewController.m
@interface CoreDataTableViewController()
@property (nonatomic) BOOL beganUpdates;
@end
@implementation CoreDataTableViewController
#pragma mark - Properties
@synthesize fetchedResultsController = _fetchedResultsController;
@synthesize suspendAutomaticTrackingOfChangesInManagedObjectContext = _suspendAutomaticTrackingOfChangesInManagedObjectContext;
@synthesize debug = _debug;
@synthesize beganUpdates = _beganUpdates;
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return YES;
}
#pragma mark - Fetching
- (void)performFetch
{
if (self.fetchedResultsController) {
if (self.fetchedResultsController.fetchRequest.predicate) {
if (self.debug) NSLog(@"[%@ %@] fetching %@ with predicate: %@", NSStringFromClass([self class]), NSStringFromSelector(_cmd), self.fetchedResultsController.fetchRequest.entityName, self.fetchedResultsController.fetchRequest.predicate);
} else {
if (self.debug) NSLog(@"[%@ %@] fetching all %@ (i.e., no predicate)", NSStringFromClass([self class]), NSStringFromSelector(_cmd), self.fetchedResultsController.fetchRequest.entityName);
}
NSError *error;
[self.fetchedResultsController performFetch:&error];
if (error) NSLog(@"[%@ %@] %@ (%@)", NSStringFromClass([self class]), NSStringFromSelector(_cmd), [error localizedDescription], [error localizedFailureReason]);
} else {
if (self.debug) NSLog(@"[%@ %@] no NSFetchedResultsController (yet?)", NSStringFromClass([self class]), NSStringFromSelector(_cmd));
}
[self.tableView reloadData];
}
- (void)setFetchedResultsController:(NSFetchedResultsController *)newfrc
{
NSFetchedResultsController *oldfrc = _fetchedResultsController;
if (newfrc != oldfrc) {
_fetchedResultsController = newfrc;
newfrc.delegate = self;
if ((!self.title || [self.title isEqualToString:oldfrc.fetchRequest.entity.name]) && (!self.navigationController || !self.navigationItem.title)) {
self.title = newfrc.fetchRequest.entity.name;
}
if (newfrc) {
if (self.debug) NSLog(@"[%@ %@] %@", NSStringFromClass([self class]), NSStringFromSelector(_cmd), oldfrc ? @"updated" : @"set");
[self performFetch];
} else {
if (self.debug) NSLog(@"[%@ %@] reset to nil", NSStringFromClass([self class]), NSStringFromSelector(_cmd));
[self.tableView reloadData];
}
}
}
#pragma mark - UITableViewDataSource
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[self.fetchedResultsController sections] count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [[[self.fetchedResultsController sections] objectAtIndex:section] numberOfObjects];
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
return [[[self.fetchedResultsController sections] objectAtIndex:section] name];
}
- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index
{
return [self.fetchedResultsController sectionForSectionIndexTitle:title atIndex:index];
}
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView
{
return [self.fetchedResultsController sectionIndexTitles];
}
#pragma mark - NSFetchedResultsControllerDelegate
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
if (!self.suspendAutomaticTrackingOfChangesInManagedObjectContext) {
[self.tableView beginUpdates];
self.beganUpdates = YES;
}
}
- (void)controller:(NSFetchedResultsController *)controller
didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
atIndex:(NSUInteger)sectionIndex
forChangeType:(NSFetchedResultsChangeType)type
{
if (!self.suspendAutomaticTrackingOfChangesInManagedObjectContext)
{
switch(type)
{
case NSFetchedResultsChangeInsert:
[self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
}
- (void)controller:(NSFetchedResultsController *)controller
didChangeObject:(id)anObject
atIndexPath:(NSIndexPath *)indexPath
forChangeType:(NSFetchedResultsChangeType)type
newIndexPath:(NSIndexPath *)newIndexPath
{
if (!self.suspendAutomaticTrackingOfChangesInManagedObjectContext)
{
switch(type)
{
case NSFetchedResultsChangeInsert:
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeUpdate:
[self.tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeMove:
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
}
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
if (self.beganUpdates) [self.tableView endUpdates];
}
- (void)endSuspensionOfUpdatesDueToContextChanges
{
_suspendAutomaticTrackingOfChangesInManagedObjectContext = NO;
}
- (void)setSuspendAutomaticTrackingOfChangesInManagedObjectContext:(BOOL)suspend
{
if (suspend) {
_suspendAutomaticTrackingOfChangesInManagedObjectContext = YES;
} else {
[self performSelector:@selector(endSuspensionOfUpdatesDueToContextChanges) withObject:0 afterDelay:0];
}
}
@end
最后但并非最不重要的一点是，我有HomeViewController的头文件，该头文件实现了CoreDataTableViewController。希望这有助于更好地解释我所拥有的。
HomeViewController.h
#import <UIKit/UIKit.h>
#import <FacebookSDK/FacebookSDK.h>
#import "CoreDataTableViewController.h"
@interface HomeViewController : CoreDataTableViewController
@property (strong, nonatomic) UIManagedDocument *shindyDatabase;
@property (nonatomic, strong) NSFetchedResultsController *fetchedResultsController;
@end
最佳答案
很难知道发生了什么，但是，我认为您需要在块完成后执行以下步骤(我想是因为我在您的代码中看不到任何相似之处)。
所以，
NSError *error = nil;
if (![[self fetchedResultsController] performFetch:&error]) {
// error handling here...
}
[yourTable reloadData];
尝试让我知道。如果不起作用，请尝试编辑一个最低限度的问题，因为要遵循的代码太多。
希望能有所帮助。
关于objective-c - NSFetchedResultsController和UITableViewController无法通信，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/14049630/