核心数据在应用启动时复制TableView单元格 [英] Core Data Duplicating TableView Cells Upon App Launch

问题描述

当我重新启动我的应用程序时，我的表视图中的单元格被复制。

When I relaunch my app, my cells in my table view are duplicated. Otherwise they are fine when being added and deleted, etc.

以下是我的代码：

@implementation RoutineTableViewController

@synthesize routineTableView;
@synthesize eventsArray;
@synthesize entered;
@synthesize managedObjectContext;

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    if (managedObjectContext == nil) 
    { 
        managedObjectContext = [(CurlAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; 
    }

    NSFetchRequest *request = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Routine" inManagedObjectContext:managedObjectContext];
    [request setEntity:entity];

    NSError *error = nil;
    NSMutableArray *mutableFetchResults = [[managedObjectContext executeFetchRequest:request error:&error] mutableCopy];
    if (mutableFetchResults == nil) {
        // Handle the error.
    }
    [self setEventsArray:mutableFetchResults];
    [mutableFetchResults release];
    [request release];

    UIBarButtonItem * addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(showPrompt)];
    [self.navigationItem setLeftBarButtonItem:addButton];
    [addButton release];

    UIBarButtonItem *editButton = [[UIBarButtonItem alloc]initWithTitle:@"Edit" style:UIBarButtonItemStyleBordered target:self action:@selector(toggleEdit)];
    self.navigationItem.rightBarButtonItem = editButton;
    [editButton release];

    [super viewDidLoad];
}

- (void)viewDidUnload
{
    self.eventsArray = nil;
    [super viewDidUnload];
}

-(void)toggleEdit
{
    [self.routineTableView setEditing: !self.routineTableView.editing animated:YES];

    if (self.routineTableView.editing)
        [self.navigationItem.rightBarButtonItem setTitle:@"Done"];
    else
        [self.navigationItem.rightBarButtonItem setTitle:@"Edit"];
}

- (void)dealloc
{
    [managedObjectContext release];
    [eventsArray release];
    [entered release];
    [super dealloc];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

#pragma mark -
#pragma mark Add an event

-(void)addEvent
{    
    Routine *routine = (Routine *)[NSEntityDescription insertNewObjectForEntityForName:@"Routine" inManagedObjectContext:managedObjectContext];

    routine.name=entered;

    NSError *error = nil;
    if (![managedObjectContext save:&error]) {
        // Handle the error.
    }
    NSLog(@"%@", error);

    /*
    [eventsArray insertObject:routine atIndex:0];

    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];

    [self.routineTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];

    [self.routineTableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES];
     */
     }

-(void)showPrompt
{
    AlertPrompt *prompt = [AlertPrompt alloc];
    prompt = [prompt initWithTitle:@"Add Workout Day" message:@"\n \n Please enter title for workout day" delegate:self cancelButtonTitle:@"Cancel" okButtonTitle:@"Add"];
    [prompt show];
    [prompt release];
}

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex
{


    if (buttonIndex != [alertView cancelButtonIndex])
    {
        entered = [(AlertPrompt *)alertView enteredText];

        if(eventsArray && entered)
        {
            Routine *tempRoutine = (Routine *)[NSEntityDescription insertNewObjectForEntityForName:@"Routine" inManagedObjectContext:managedObjectContext]; 
            tempRoutine.name = entered;
            [eventsArray addObject:tempRoutine];
            [routineTableView reloadData];
            [self addEvent];
            NSLog(@"tempRoutine.name is: %@",tempRoutine.name);
        }
    }
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [eventsArray count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil)
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
    }

    Routine *tempRoutine = (Routine *)[eventsArray objectAtIndex:indexPath.row];
    cell.textLabel.text = tempRoutine.name;
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

    return cell;
}

// 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;
}

-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
 {

     if (editingStyle == UITableViewCellEditingStyleDelete) {

         // Delete the managed object at the given index path.
         NSManagedObject *eventToDelete = [eventsArray objectAtIndex:indexPath.row];
         [managedObjectContext deleteObject:eventToDelete];

         // Update the array and table view.
         [eventsArray removeObjectAtIndex:indexPath.row];
         [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];

         // Commit the change.
         NSError *error = nil;
         if (![managedObjectContext save:&error]) {
             // Handle the error.
         }
     }

推荐答案

I

Routine *tempRoutine = (Routine *)[NSEntityDescription insertNewObjectForEntityForName:@"Routine" inManagedObjectContext:managedObjectContext]; 
            tempRoutine.name = entered;
        ---->    [eventsArray addObject:tempRoutine];
            [routineTableView reloadData];
         ---->   [self addEvent]; //comment this line in alertViewDelegate

或者您可以使用以下代码更改.....有语法错误

or you can use following code changes..... it may have syntax error

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex
{


    if (buttonIndex != [alertView cancelButtonIndex])
    {
        entered = [(AlertPrompt *)alertView enteredText];

        if(eventsArray && entered)
        {
           [self addEvent];

        }
    }
}


-(void)addEvent
{    
    Routine *routine = (Routine *)[NSEntityDescription insertNewObjectForEntityForName:@"Routine" inManagedObjectContext:managedObjectContext];

    routine.name=entered;

    NSError *error = nil;
    if (![managedObjectContext save:&error]) {
        // Handle the error.
    }
    NSLog(@"%@", error);


    [eventsArray addObject:routine];

    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:[eventsArray count] inSection:0];

    [self.routineTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];

    [self.routineTableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES];

     }

谢谢，

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