Question

现在已经过了3个星期，我一直在寻求这个网站的帮助，使用Core Data进行这个简单的保存/获取功能，但我无法让它工作。我不断收到人们的不同建议，并相应地更改我的代码，但永远无法使其正常工作。

非常令人沮丧的是，由于这个简单的错误让我花了很长时间，但我在击中之前的一周内完成了100倍的工作。在学习如何编程时，它真的很无聊。

以下是该方案： TableView默认为空，直到用户通过导航栏中的+按钮输入名称字符串。输入的字符串应该将一个单元格添加到视图中，并将名称作为标题。它应该保存到内存中，并在重新启动应用程序时获取。

问题： 我收到以下错误@ line：cell.textLabel.text = [eventsArray objectAtIndex:indexPath.row];

方法：- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

2011-04-11 22:40:49.824 Curl[2244:207] -[Routine isEqualToString:]: unrecognized selector sent to instance 0x5c09ad0
2011-04-11 22:40:50.005 Curl[2244:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Routine isEqualToString:]: unrecognized selector sent to instance 0x5c09ad0'

我的数据模型：

enter image description here

ViewController代码：

`@implementation RoutineTableViewController

@synthesize tableView;
@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.tableView setEditing: !self.tableView.editing animated:YES];

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

- (void)dealloc
{
    [managedObjectContext release];
    [eventsArray 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.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];

    [self.tableView 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)
        {
            [eventsArray addObject:entered];
            [tableView reloadData];
            [self addEvent];
        }
    }
}

#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";

    // Dequeue or create a new cell.

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

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

    cell.textLabel.text = [eventsArray objectAtIndex:indexPath.row];

    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.
         }
     }
 }`

Answer 1

cell.textLabel.text = [eventsArray objectAtIndex:indexPath.row];

这导致了这个问题，因为.......你将例程类对象作为文本分配给textLabel ......

cell.textLabel.text = [(Routine *)[eventsArray objectAtIndex:indexPath.row] <thePropertyYouWishToAssign from Routine class>];

或＆lt; * * 更新代码 * ** ＆gt;

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

＆lt; * * 更新代码 * ** ＆gt; < / p>

在你的情况下。

警告视图委托中的

.....

 if(eventsArray && entered)
    {
//******it will also insert object in coredata.... is it duplicating data?
           Routine *tempRoutine = (Routine *)[NSEntityDescription insertNewObjectForEntityForName:@"Routine" inManagedObjectContext:managedObjectContext]; tempRoutine.name = entered;
           [eventsArray addObject:tempRoutine];
           [tempRoutine release];
            [tableView reloadData];
             [self addEvent];
     }

谢谢，

似乎无法修复此基本保存/获取请求

1 个答案: