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我使用Core Data來跟蹤簡單待辦事項列表中的條目。我用一個簡單的UIAlertView和UITextField爲用戶添加新條目。這些條目使用NSManagedObject保存，但不會添加最新的入門到tableview中，即使是在我運行[self.tableView reloadData];添加新項目（使用核心數據）後UITableView不會更新
這GIF展示它是如何工作現在：
頭文件：
#import <UIKit/UIKit.h>
@interface PakkelisteViewController : UITableViewController <UIAlertViewDelegate>
@end
實現文件：
#import "PakkelisteViewController.h"
#import "AUFToDoItem.h"
@interface PakkelisteViewController()
@property NSMutableArray *toDoItems;
-(IBAction)addNewToDoItem;
@end
@implementation PakkelisteViewController
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// defaultTodos = [[NSMutableArray alloc] initWithObjects:@"Badetøy", @"Skrivesaker", @"Lommepenger", @"Godt humør", nil];
self.toDoItems = [[NSMutableArray alloc] init];
[self loadInitialData];
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
}
-(void)viewWillAppear:(BOOL)animated
{
// Fetch the devices from persistent data store
NSManagedObjectContext *managedObjectContext = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"AUFToDoItem"];
self.toDoItems = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy];
[self.tableView reloadData];
}
-(void)loadInitialData
{
}
-(IBAction)addNewToDoItem
{
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Legg til ny" message:nil delegate:self cancelButtonTitle:@"Avbryt" otherButtonTitles:@"Legg til", nil];
[alertView setAlertViewStyle:UIAlertViewStylePlainTextInput];
[[alertView textFieldAtIndex:0] setPlaceholder:@"Rent undertøy"];
[[alertView textFieldAtIndex:0] setAutocapitalizationType:UITextAutocapitalizationTypeSentences];
[alertView show];
}
-(BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView
{
NSString *inputText = [[alertView textFieldAtIndex:0] text];
if ([inputText length] > 0)
{
return YES;
}
else
{
return NO;
}
}
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex == 1)
{
NSManagedObjectContext *context = [self managedObjectContext];
// Create a new managed object
NSManagedObject *toDoItem = [NSEntityDescription insertNewObjectForEntityForName:@"AUFToDoItem" inManagedObjectContext:context];
[toDoItem setValue:[alertView textFieldAtIndex:0].text forKey:@"itemName"];
[toDoItem setValue:[NSDate date] forKey:@"creationDate"];
[toDoItem setValue:NO forKey:@"completed"];
NSError *error = nil;
// Save the object to persistent store
if (![context save:&error]) {
NSLog(@"Can't Save! %@ %@", error, [error localizedDescription]);
}
[self dismissViewControllerAnimated:YES completion:nil];
[self.tableView reloadRowsAtIndexPaths:[self.tableView indexPathsForVisibleRows] withRowAnimation:UITableViewRowAnimationFade];
// [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 the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return self.toDoItems.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
NSManagedObject *toDoItem = [self.toDoItems objectAtIndex:indexPath.row];
cell.textLabel.text = [toDoItem valueForKey:@"itemName"];
if ((BOOL)[toDoItem valueForKey:@"completed"] == YES)
{
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
else
{
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
/*
[tableView deselectRowAtIndexPath:indexPath animated:NO];
AUFToDoItem *tappedItem = [self.toDoItems objectAtIndex:indexPath.row];
tappedItem.completed = !tappedItem.completed;
[tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationNone];
*/
}
-(NSManagedObjectContext *)managedObjectContext {
NSManagedObjectContext *context = nil;
id delegate = [[UIApplication sharedApplication] delegate];
if ([delegate performSelector:@selector(managedObjectContext)]) {
context = [delegate managedObjectContext];
}
return context;
}
// 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
{
NSManagedObjectContext *context = [self managedObjectContext];
if (editingStyle == UITableViewCellEditingStyleDelete) {
[context deleteObject:[self.toDoItems objectAtIndex:indexPath.row]];
NSError *error = nil;
if (![context save:&error])
{
NSLog(@"Can't delete! %@ %@", error, [error localizedDescription]);
return;
}
[self.toDoItems removeObjectAtIndex:indexPath.row];
[self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
}
/*
// 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 storyboard-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.
}
*/
@end
if（cell == nil）in before add cell = nil;這個想法在我的代碼中完美工作。 –
取消註釋[self.tableView reloadData]; 它會正常工作。 –
@DarshanKunjadiya：不確定你的意思？ –