我正在关注Tim Roadley教程http://timroadley.com/2012/03/05/core-data-basics-part-7-search-bars/尝试向我的项目添加搜索栏，但我在执行应用程序时收到异常。这是例外：
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'unable to dequeue a cell with identifier Cell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard'.
这是我的代码，用教程代码更新。
#import "ToDoItemsTableViewController.h"
#import "AppDelegate.h"
#import "AddToDoItemViewController.h"
#import "ToDoSubItemsTableViewController.h"
@interface ToDoItemsTableViewController ()
@property (nonatomic, strong)NSManagedObjectContext *managedObjectContext;
@property (nonatomic, strong)NSFetchedResultsController *fetchedResultsController;
@end
@implementation ToDoItemsTableViewController
@synthesize searchResults;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
-(NSManagedObjectContext *)managedObjectContext{
return [(AppDelegate*)[[UIApplication sharedApplication]delegate]managedObjectContext];
}
- (void)viewDidLoad
{
[super viewDidLoad];
//navigation bar background image
[self.navigationController.navigationBar
setBackgroundImage:[UIImage imageNamed:@"navBar.png"]
forBarMetrics:UIBarMetricsDefault];
NSDictionary *textAttributes = [NSDictionary dictionaryWithObjectsAndKeys:
[UIColor blackColor],NSForegroundColorAttributeName,
[UIColor blackColor],NSBackgroundColorAttributeName,nil];
self.navigationController.navigationBar.titleTextAttributes = textAttributes;
NSError *error = nil;
if (![[self fetchedResultsController]performFetch:&error]){
NSLog(@"Error %@",error);
abort();
}
self.searchResults = [NSMutableArray arrayWithCapacity:[[self.fetchedResultsController fetchedObjects] count]];
[self.tableView reloadData];
}
-(void) viewWillAppear:(BOOL)animated{
[self.tableView reloadData];
}
- (void)viewDidUnload
{
self.searchResults = nil;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if ([[segue identifier]isEqualToString:@"addToDoItem"]){
UINavigationController *navigationController = segue.destinationViewController;
AddToDoItemViewController *addToDoItemViewController = (AddToDoItemViewController*)navigationController.topViewController;
ToDoItem *addToDoItem = [NSEntityDescription insertNewObjectForEntityForName:@"ToDoItem" inManagedObjectContext:self.managedObjectContext];
addToDoItem.todoDueDate = [NSDate date];
addToDoItemViewController.addToDoItem = addToDoItem;
}
if ([[segue identifier] isEqualToString:@"toToDoSubItems"]){
ToDoSubItemsTableViewController *todoSubItemsTableViewController = [segue destinationViewController];
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
ToDoItem *selectedToDoItem = (ToDoItem*)[self.fetchedResultsController objectAtIndexPath:indexPath];
todoSubItemsTableViewController.selectedToDoItem = selectedToDoItem;
}
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[self.fetchedResultsController sections]count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (tableView == self.searchDisplayController.searchResultsTableView)
{
return [self.searchResults count];
}
else {
id<NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections]objectAtIndex:section];
return [sectionInfo numberOfObjects];
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
// Configure the cell...
ToDoItem *toDoItem = nil;
if (tableView == self.searchDisplayController.searchResultsTableView)
{
NSLog(@"Configuring cell to show search results");
toDoItem = [self.searchResults objectAtIndex:indexPath.row];
}
else
{
ToDoItem *todoItem = [self.fetchedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text = todoItem.todoName;
NSDate *fechaToDO = todoItem.todoDueDate;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"EEEE, dd MMMM YYYY"];
NSString *fechaToDo = [dateFormatter stringFromDate:fechaToDO];
cell.detailTextLabel.text = fechaToDo;
}
return cell;
}
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
static NSString *header = @"customHeader";
UITableViewHeaderFooterView *vHeader;
vHeader = [tableView dequeueReusableHeaderFooterViewWithIdentifier:header];
if (!vHeader) {
vHeader = [[UITableViewHeaderFooterView alloc] initWithReuseIdentifier:header];
vHeader.textLabel.backgroundColor = [UIColor redColor];
vHeader.textLabel.textColor = [UIColor whiteColor];
vHeader.contentView.backgroundColor = [UIColor redColor];
}
if (section == 0) {
vHeader.textLabel.backgroundColor = [UIColor redColor];
vHeader.textLabel.textColor = [UIColor whiteColor];
vHeader.contentView.backgroundColor = [UIColor redColor];
}
else if (section == 1) {
vHeader.textLabel.backgroundColor = [UIColor orangeColor];
vHeader.textLabel.textColor = [UIColor blueColor];
vHeader.contentView.backgroundColor = [UIColor orangeColor];
}
else if (section == 2) {
vHeader.textLabel.backgroundColor = [UIColor greenColor];
vHeader.textLabel.textColor = [UIColor whiteColor];
vHeader.contentView.backgroundColor = [UIColor greenColor];
}
vHeader.textLabel.text = [self tableView:tableView titleForHeaderInSection:section];
return vHeader;
}
-(NSString*)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{
id <NSFetchedResultsSectionInfo> theSection = [[self.fetchedResultsController sections]objectAtIndex:section];
NSString *sectionname = [theSection name];
if ([sectionname isEqualToString:@"0"]){
NSString *valor = [NSString stringWithFormat:@"O V E R D U E (%d)", [self.tableView
numberOfRowsInSection:section]];
return valor;
}
else if ([sectionname isEqualToString:@"1"]){
NSString *valor = [NSString stringWithFormat:@"T O D A Y (%d)", [self.tableView
numberOfRowsInSection:section]];
return valor;
}
else if ([sectionname isEqualToString:@"2"]){
NSString *valor = [NSString stringWithFormat:@"U P C O M I N G (%d)", [self.tableView
numberOfRowsInSection:section]];
return valor;
}
if ([[self.fetchedResultsController sections]count]>0){
id<NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections]objectAtIndex:section];
return [sectionInfo name];
}
else{
return nil;
}
}
#pragma mark - Fetched Results Controller Section
-(NSFetchedResultsController*)fetchedResultsController{
if (_fetchedResultsController != nil){
return _fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]init];
NSManagedObjectContext *context = self.managedObjectContext;
NSEntityDescription *entity = [NSEntityDescription entityForName:@"ToDoItem" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]initWithKey:@"todoDueDate" ascending:YES];
NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc]initWithKey:@"todoName" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc]initWithObjects:sortDescriptor,sortDescriptor1, nil];
fetchRequest.sortDescriptors = sortDescriptors;
_fetchedResultsController = [[NSFetchedResultsController alloc]initWithFetchRequest:fetchRequest managedObjectContext:context sectionNameKeyPath:@"sectionIdentifier" cacheName:nil];
_fetchedResultsController.delegate = self;
return _fetchedResultsController;
}
#pragma mark - Fetched Results Controller Delegates
-(void)controllerWillChangeContent:(NSFetchedResultsController *)controller {
[self.tableView beginUpdates];
}
-(void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
[self.tableView endUpdates];
}
-(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:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeUpdate:{
ToDoItem *changeToDoItem = [self.fetchedResultsController objectAtIndexPath:indexPath];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
cell.textLabel.text = changeToDoItem.todoName;
NSDate *fechaToDO = changeToDoItem.todoDueDate;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"EEEE, dd MMMM YYYY"];
NSString *fechaToDo = [dateFormatter stringFromDate:fechaToDO];
cell.detailTextLabel.text = fechaToDo;
}
break;
case NSFetchedResultsChangeMove:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
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:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return YES;
}
*/
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
NSManagedObjectContext *context = [self managedObjectContext];
ToDoItem *ToDoItemToDelete = [self.fetchedResultsController objectAtIndexPath:indexPath];
[context deleteObject:ToDoItemToDelete];
NSError *error = nil;
if (![context save:&error]){
NSLog(@"Error: %@",error);
}
}
}
/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
}
*/
/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/
/*
#pragma mark - Navigation
// In a story board-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
#pragma mark -
#pragma mark Content Filtering
- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
NSLog(@"Previous Search Results were removed.");
[self.searchResults removeAllObjects];
for (ToDoItem *toDoItem in [self.fetchedResultsController fetchedObjects])
{
if ([scope isEqualToString:@"All"] || [toDoItem.todoName isEqualToString:scope])
{
NSComparisonResult result = [toDoItem.todoName compare:searchText
options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch)
range:NSMakeRange(0, [searchText length])];
if (result == NSOrderedSame)
{
NSLog(@"Adding toDoItem.todoName '%@' to searchResults as it begins with search text '%@'", toDoItem.todoName, searchText);
[self.searchResults addObject:toDoItem];
}
}
}
}
#pragma mark -
#pragma mark UISearchDisplayController Delegate Methods
- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
[self filterContentForSearchText:searchString scope:@"All"];
return YES;
}
- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchScope:(NSInteger)searchOption
{
[self filterContentForSearchText:[self.searchDisplayController.searchBar text] scope:@"All"];
return YES;
}
@end
欢迎任何建议或帮助。
答案 0 :(得分：1)
尝试以这种方式纠正您的代码：
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
重要说明：您必须使用以下命令注册类或nib文件 registerNib：forCellReuseIdentifier：或 registerClass：forCellReuseIdentifier：调用它之前的方法 方法
这是另一种方法：
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];