Question

My app is crashing (freezing) when I click the add button on my uialertview and it is supposed to add a cell to the table. The error is related to the line of code I posted here:

Here is the error message:

SIGABRT at this line: cell.textLabel.text = [self.eventsArray objectAtIndex:indexPath.row];
Ok i figured out the problem is because eventArray holds an object rather than the string I need. How can I modify my code so that the save/fetch works correctly?

What is supposed to happen is that when the user enters a string into the alert view and presses ok, it is supposed to save into the name attribute of the routine entity and the table view should update itself accordingly.

Here is my viewController Code:

#import "RoutineTableViewController.h"
#import "AlertPrompt.h"
#import "Routine.h"
#import "CurlAppDelegate.h"

@implementation RoutineTableViewController

@synthesize tableView;
@synthesize eventsArray;
@synthesize managedObjectContext;

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

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

-(void)addEvent
{
    CurlAppDelegate *curlAppDelegate = [[UIApplication sharedApplication] delegate];
    NSManagedObjectContext *context = [curlAppDelegate managedObjectContext];

    Routine *routine = (Routine *)[NSEntityDescription insertNewObjectForEntityForName:@"Routine" inManagedObjectContext:context];

    NSManagedObject *newRoutineEntry;
    newRoutineEntry = [NSEntityDescription insertNewObjectForEntityForName:@"Routine" inManagedObjectContext:context];

    NSError *error = nil;
    if (![context 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];
}



#pragma mark - View lifecycle

- (void)viewDidLoad
{
    CurlAppDelegate *curlAppDelegate = [[UIApplication sharedApplication] delegate];
    NSManagedObjectContext *context = [curlAppDelegate managedObjectContext];

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

    NSError *error = nil;
    NSMutableArray *mutableFetchResults = [[context 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)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)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])
    {
        NSString *entered = [(AlertPrompt *)alertView enteredText];
        if(eventsArray && entered)
        {
            [eventsArray addObject:entered];
            [tableView reloadData];
            [self addEvent];
        }
    }
}

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

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
}

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#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:UITableViewCellEditingStyleDelete reuseIdentifier:CellIdentifier] autorelease];
    cell.textLabel.text = [self.eventsArray objectAtIndex:indexPath.row];

    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;
}

Here is console output:

2011-03-30 02:31:44.725 Curl[3303:707] -[Routine isEqualToString:]: unrecognized selector sent to instance 0x19d650
2011-03-30 02:31:44.824 Curl[3303:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Routine isEqualToString:]: unrecognized selector sent to instance 0x19d650'
*** Call stack at first throw:
(
    0   CoreFoundation                      0x3234564f __exceptionPreprocess + 114
    1   libobjc.A.dylib                     0x36588c5d objc_exception_throw + 24
    2   CoreFoundation                      0x323491bf -[NSObject(NSObject) doesNotRecognizeSelector:] + 102
    3   CoreFoundation                      0x32348649 ___forwarding___ + 508
    4   CoreFoundation                      0x322bf180 _CF_forwarding_prep_0 + 48
    5   UIKit                               0x354fcf65 -[UILabel setText:] + 32
    6   Curl                                0x0000682b -[RoutineTableViewController tableView:cellForRowAtIndexPath:] + 286
    7   UIKit                               0x355589ed -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:] + 516
    8   UIKit                               0x3555876b -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:] + 34
    9   UIKit                               0x3562a053 -[_UITableViewUpdateSupport(Private) _setupAnimationsForNewlyInsertedCells] + 3722
    10  UIKit                               0x35627b99 -[_UITableViewUpdateSupport initWithTableView:updateItems:oldRowData:newRowData:oldRowRange:newRowRange:context:] + 320
    11  UIKit                               0x35626dc1 -[UITableView(_UITableViewPrivate) _updateWithItems:withOldRowData:oldRowRange:newRowRange:context:] + 972
    12  UIKit                               0x35626473 -[UITableView(_UITableViewPrivate) _endCellAnimationsWithContext:] + 4750
    13  UIKit                               0x3562501d -[UITableView _updateRowsAtIndexPaths:updateAction:withRowAnimation:] + 204
    14  UIKit                               0x356302b9 -[UITableView insertRowsAtIndexPaths:withRowAnimation:] + 20
    15  Curl                                0x00005dc3 -[RoutineTableViewController addEvent] + 398
    16  Curl                                0x000064b1 -[RoutineTableViewController alertView:willDismissWithButtonIndex:] + 228
    17  UIKit                               0x35621ee1 -[UIAlertView dismissWithClickedButtonIndex:animated:] + 192
    18  UIKit                               0x35621d25 -[UIAlertView(Private) _buttonClicked:] + 280
    19  CoreFoundation                      0x322b5571 -[NSObject(NSObject) performSelector:withObject:withObject:] + 24
    20  UIKit                               0x35513ec9 -[UIApplication sendAction:to:from:forEvent:] + 84
    21  UIKit                               0x35513e69 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 32
    22  UIKit                               0x35513e3b -[UIControl sendAction:to:forEvent:] + 38
    23  UIKit                               0x35513b8d -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 356
    24  UIKit                               0x35514423 -[UIControl touchesEnded:withEvent:] + 342
    25  UIKit                               0x35512bf5 -[UIWindow _sendTouchesForEvent:] + 368
    26  UIKit                               0x3551256f -[UIWindow sendEvent:] + 262
    27  UIKit                               0x354fb313 -[UIApplication sendEvent:] + 298
    28  UIKit                               0x354fac53 _UIApplicationHandleEvent + 5090
    29  GraphicsServices                    0x30557e77 PurpleEventCallback + 666
    30  CoreFoundation                      0x3231ca97 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 26
    31  CoreFoundation                      0x3231e83f __CFRunLoopDoSource1 + 166
    32  CoreFoundation                      0x3231f60d __CFRunLoopRun + 520
    33  CoreFoundation                      0x322afec3 CFRunLoopRunSpecific + 230
    34  CoreFoundation                      0x322afdcb CFRunLoopRunInMode + 58
    35  GraphicsServices                    0x3055741f GSEventRunModal + 114
    36  GraphicsServices                    0x305574cb GSEventRun + 62
    37  UIKit                               0x35525d69 -[UIApplication _run] + 404
    38  UIKit                               0x35523807 UIApplicationMain + 670
    39  Curl                                0x0000304f main + 82
    40  Curl                                0x00002ff8 start + 40
)
terminate called after throwing an instance of 'NSException'
(gdb) 

Answer 1

Here is the issue in the above code

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

because

 [eventsArray insertObject:routine atIndex:0];

eventsArray hold the object of Routine class not NSString.
So Do’nt do

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

Edited:

Routine* myRoutine = [self.eventsArray objectAtIndex:indexPath.row];
//you need to get your stored text value from Routine class 
//let's say it myText
cell.textLabel.text = myText;