NSFetchedResultsControllerDelegate方法未从UIViewController调用

Question

只是一个警告，这是我的第一个问题，对我温柔。

我有一个符合NSFetchedResultsControllerDelegate协议的UITableViewController。一切都很完美。我想将其更改为UIViewController，以便能够向视图添加更多内容而不仅仅是tableview。我创建了tableView属性并设置了委托和数据源。一切正常，除了没有调用FRC委托方法并且表没有更新。插入，编辑和删除存储在数据库中，但是当我在上下文中更改某些内容时，表不会更新。

所有代码都是使用获取结果控制器的基本模板代码。当它在行中设置委托时：

aFetchedResultsController.delegate = self;

应该正确设置委托，但事实并非如此。同样，我做的唯一更改是从UITableViewController中删除单词Table。它适用于UITableViewController，但不适用于UIViewController。我对此进行了广泛的研究，但没有找到答案。

感谢。

以下是一些代码：

#import <UIKit/UIKit.h>
#import <CoreData/CoreData.h>
.
.
.

@class NowWhatDetailViewController;
@class Event;

@interface NowWhatMasterViewController : UITableViewController <NSFetchedResultsControllerDelegate, ChangeDateViewControllerDelgate, EditEventViewControllerDelgate, PasswordViewControllerDelegate,
    UITableViewDelegate, UITableViewDataSource> {

    NSMutableArray *saveButtonItems;

    IBOutlet UILabel *nextEventLabel;
    IBOutlet UILabel *timeToNextEventLabel;


}


@property (strong, nonatomic) NowWhatDetailViewController *detailViewController;
@property (strong, nonatomic) NSFetchedResultsController *fetchedResultsController;
@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;

@property (nonatomic, weak) id <ChangeDateViewControllerDelgate> delegate;

@property (nonatomic, retain) IBOutlet UITableView *tableView;
.
.
.

@end


And the important sections of NowWhatMasterViewController.m


#import "NowWhatMasterViewController.h"


@interface NowWhatMasterViewController () {


}

@end

@implementation NowWhatMasterViewController {

    Event *lastEditedEvent;

}


- (void)viewDidLoad
{
    [super viewDidLoad];


    [self performFetch];

    [[self.splitViewController.viewControllers lastObject] topViewController];

    self.detailViewController.viewNSDate = self.viewNSDate;
    self.detailViewController.viewDate = self.viewDate;
    self.detailViewController.viewSchedule = self.viewSchedule;
    self.detailViewController.managedObjectContext = self.managedObjectContext;
    self.detailViewController.fetchedResultsControllerDetail = self.fetchedResultsController;

    [self.detailViewController updateDetailView];


    // show the bottom toolbar
    [self.navigationController setToolbarHidden:NO];

    saveButtonItems = [self.toolbarItems mutableCopy];

    nextEventLabel.text = @"next event";
    timeToNextEventLabel.text = @"starts in ## minutes";



}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
    self.fetchedResultsController = nil;

}

- (void)viewDidUnload {
    self.fetchedResultsController = nil;
}

#pragma mark - Table View

/*
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return [dayEvents count];
}
*/

- (void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath
{

    Event *event = [self.fetchedResultsController objectAtIndexPath:indexPath];

    [self performSegueWithIdentifier:@"EditEvent" sender:event];
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][section];
    return [sectionInfo numberOfObjects];
    //return [dayEvents count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"EventCell"];
    [self configureCell:cell atIndexPath:indexPath];
    return cell;
}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.

    if (_isLocked) {
        return NO;
    } else {
        return YES;
    }
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
        [context deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];

        NSError *error = nil;
        if (![context save:&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. 
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        }
    }   
}

- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    // The table view should not be re-orderable.
    return NO;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    Event *event = [self.fetchedResultsController objectAtIndexPath:indexPath];
    [event toggleChecked];
    [self configureCheckmarkForCell:cell withEvent:event];

    [tableView deselectRowAtIndexPath:indexPath animated:YES];


    // this updates the detail controller when a row is selected.  Not sure we want to do that
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
        NSManagedObject *object = [[self fetchedResultsController] objectAtIndexPath:indexPath];
        self.detailViewController.detailItem = object;
    }
}


#pragma mark - Fetched results controller

- (NSFetchedResultsController *)fetchedResultsController
{
    if (_fetchedResultsController != nil) {
        return _fetchedResultsController;
    }


    NSLog(@"the fetched results controller is getting the events for %@", self.viewNSDate);

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    // Edit the entity name as appropriate.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" 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:@"eventNSDate" ascending:YES];
    NSArray *sortDescriptors = @[sortDescriptor];
    [fetchRequest setSortDescriptors:sortDescriptors];

    // setup the predicate to return just the wanted date and schedule
    NSPredicate *requestPredicate = [NSPredicate predicateWithFormat:[NSString stringWithFormat:@"(eventDate like '%@') AND (schedule.scheduleName like '%@')", [Event returnDateString:self.viewNSDate], self.viewSchedule.scheduleName]];
    [fetchRequest setPredicate:requestPredicate];

    // Clear out any previous cache
    [NSFetchedResultsController deleteCacheWithName:@"Master"];


    // 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:@"Master"];
    aFetchedResultsController.delegate = self;
    self.fetchedResultsController = aFetchedResultsController;

    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. 
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

    // manually set the delegate?

    return _fetchedResultsController;
}    

- (void)performFetch
{
    NSError *error;
    if (![self.fetchedResultsController performFetch:&error]) {
        //FATAL_CORE_DATA_ERROR(error);
        NSLog(@"database error");
        return;
    }
}



- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
    [self.tableView beginUpdates];
}

- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
           atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
    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
{
    UITableView *tableView = self.tableView;

    switch(type) {
        case NSFetchedResultsChangeInsert:
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeDelete:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeUpdate:
            [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
            break;

        case NSFetchedResultsChangeMove:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
    }
}

- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
    [self.tableView endUpdates];
}