我一直在使用核心数据来存储一些信息的项目，我有一个带有UISegmentedControl的UITableViewController和两个NSFetchedResultsController，因为我需要在切换分段控件时获取不同的数据。
当我第一次打开表视图时，我可以看到对应于分段控制器的第一个索引的数据，但是当我切换到第二个索引时，数据不显示，当我回到第一个索引时分段控制也没有显示数据。
这是代码
#import "TurnHistoryVC.h"
#import "AppDelegate.h"
#import "Turn.h"
#import "TurnInfoVC.h"
#import "Favorite.h"
@interface TurnHistoryVC ()
@property (nonatomic, retain) NSFetchedResultsController *currentFRC;
@property (nonatomic, strong) NSFetchedResultsController *fetchedResultsController;
@property (nonatomic, strong) NSFetchedResultsController *favoritesResultsController;
@end
@implementation TurnHistoryVC
@synthesize fetchedResultsController = _fetchedResultsController;
@synthesize favoritesResultsController = _favoritesResultsController;
- (void)viewWillAppear:(BOOL)animated{
NSInteger *turn_id = [[NSUserDefaults standardUserDefaults] integerForKey: @"turn_noti_id"];
if (turn_id != 0) {
[self performSegueWithIdentifier:@"myTurn" sender:self];
} else {
id delegate = [[UIApplication sharedApplication] delegate];
self.managedObjectContext = [delegate managedObjectContext];
NSError *error;
self.currentFRC = self.fetchedResultsController;
if (![[self currentFRC] performFetch:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
}
}
[self.tableView reloadData];
[super viewWillAppear:animated];
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Atrás" style:UIBarButtonItemStylePlain target:nil action:nil];
[self.tableView reloadData];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[self.currentFRC sections] count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
id <NSFetchedResultsSectionInfo> sectionInfo = [[self.currentFRC sections] objectAtIndex:section];
return [sectionInfo numberOfObjects];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
// Configure the cell.
[self configureCell:cell atIndexPath:indexPath];
return cell;
}
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath {
Turn *turn = [self.currentFRC objectAtIndexPath:indexPath];
cell.textLabel.text = [NSString stringWithFormat:@"Turno no. %@", turn.turn_number];
cell.detailTextLabel.text = turn.companie_info;
cell.tag = [turn.turn_id intValue];
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
// Display the authors' names as section headings.
// return @"";
return [[[self.currentFRC sections] objectAtIndex:section] name];
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *selectedCell = [tableView cellForRowAtIndexPath:indexPath];
NSLog(@"cell id: %i", selectedCell.tag);
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
self.editButtonItem.title = @"Listo";
// [tableView ]
// Delete the managed object.
NSManagedObjectContext *context = [self.currentFRC managedObjectContext];
[context deleteObject:[self.currentFRC objectAtIndexPath:indexPath]];
NSError *error;
if (![context save:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
// abort();
}
}
}
//Metodo para cambiar el texto del boton para borrar favoritos
-(NSString *)tableView:(UITableView *)tableView titleForDeleteConfirmationButtonForRowAtIndexPath:(NSIndexPath *)indexPath {
return @"Elimiar";
}
-(void)toggleEdit{
[self.tableView setEditing:!self.tableView.editing animated:YES];
if (self.tableView.editing){
[self.navigationItem.leftBarButtonItem setTitle:@"Listo"];
}else{
[self.navigationItem.leftBarButtonItem setTitle:@"Editar"];
}
}
#pragma mark - Navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([sender isKindOfClass:[UITableViewCell class]]){
if ([segue.destinationViewController isKindOfClass:[TurnInfoVC class]]){
TurnInfoVC *turnInfoVC = segue.destinationViewController;
NSIndexPath *indexPath = [self.tableView indexPathForCell:sender];
UITableViewCell *selectedCell = [self.tableView cellForRowAtIndexPath:indexPath];
turnInfoVC.turn_id = selectedCell.tag;
}
}
}
#pragma mark - Cambio de turnos pendientes a finalizados
- (IBAction)btnTurnTypes:(UISegmentedControl *)sender {
NSError *error;
NSLog(@"cambie de tab 0");
switch (sender.selectedSegmentIndex) {
case 0:
{
self.currentFRC = self.fetchedResultsController;
[self.tableView reloadData];
}
break;
case 1:
{
self.currentFRC = self.favoritesResultsController;
[self.tableView reloadData];
NSLog(@"cambie de tab 1");
}
break;
default:
break;
}
[self.tableView reloadData];
}
#pragma mark - Fetched results controller
/*
Returns the fetched results controller. Creates and configures the controller if necessary.
*/
- (NSFetchedResultsController *)fetchedResultsController {
if (_fetchedResultsController != nil) {
}
NSLog(@"turnos pendientes");
NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Turn"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"turn_confirmation==0 AND turn_status==1"];
fetchRequest.predicate = predicate;
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Turn" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Create the sort descriptors array.
NSSortDescriptor *categoryDescriptor = [[NSSortDescriptor alloc] initWithKey:@"companie_info" ascending:YES];
NSSortDescriptor *companyDescriptor = [[NSSortDescriptor alloc] initWithKey:@"turn_number" ascending:YES];
NSArray *sortDescriptors = @[categoryDescriptor, companyDescriptor];
[fetchRequest setSortDescriptors:sortDescriptors];
_fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"companie_info" cacheName:@"Root"];
_fetchedResultsController.delegate = self;
self.currentFRC = _fetchedResultsController;
return _fetchedResultsController;
}
- (NSFetchedResultsController *)favoritesResultsController {
if (_favoritesResultsController != nil) {
}
NSLog(@"turnos finalizados");
NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Turn"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"turn_confirmation==0 AND turn_status==0"];
fetchRequest.predicate = predicate;
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Turn" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Create the sort descriptors array.
NSSortDescriptor *categoryDescriptor = [[NSSortDescriptor alloc] initWithKey:@"companie_info" ascending:YES];
NSSortDescriptor *companyDescriptor = [[NSSortDescriptor alloc] initWithKey:@"turn_number" ascending:YES];
NSArray *sortDescriptors = @[categoryDescriptor, companyDescriptor];
[fetchRequest setSortDescriptors:sortDescriptors];
// Create and initialize the fetch results controller.
_favoritesResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"companie_info" cacheName:@"Root"];
_favoritesResultsController.delegate = self;
self.currentFRC = _favoritesResultsController;
return _favoritesResultsController;
}
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
NSLog(@"actualizando fuera del if");
// The fetch controller is about to start sending change notifications, so prepare the table view for updates.
if (controller == self.currentFRC) {
NSLog(@"actualizando dentro del if");
[self.tableView beginUpdates];
}
}
- (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:UITableViewRowAnimationAutomatic];
break;
case NSFetchedResultsChangeDelete:
[tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
break;
case NSFetchedResultsChangeUpdate:
[self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
break;
case NSFetchedResultsChangeMove:
[tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
[tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
break;
}
}
- (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:UITableViewRowAnimationAutomatic];
break;
case NSFetchedResultsChangeDelete:
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationAutomatic];
break;
}
}
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
// The fetch controller has sent all current change notifications, so tell the table view to process all updates.
[self.tableView endUpdates];
}
@end
我已经尝试了这个solution，但我无法让它工作，谢谢