Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFString objectForKey:]: unrecognized selector sent to instance

Question

I have the following code in the main header file

NSMutableArray *array;
NSDictionary *dict,*dict1;

.m file contains array of dictionaries which display the item name along with their resp prices, I have displayed this in UITableView

 - (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section
   {
      return [array 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];
        }
      cell.textLabel.text=[NSString stringWithFormat:@"%@ %@",[[array objectAtIndex:indexPath.row]objectForKey:@"name"],[[array objectAtIndex:indexPath.row]objectForKey:@"price"]];
                    return cell;        
   }

when the user selects any one item it sends the dictionary another dictionary called pass to VegQuantityViewController where quantity has to multiplied with the price

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if(indexPath.row==0)
    {           
         VegQuantity *vegetarian1 = [[VegQuantity alloc] initWithNibName:@"VegQuantity" bundle:nil];    
        vegetarian1.pass=dict;
        [self presentModalViewController:vegetarian1 animated:YES];
    }
    if(indexPath.row==1)
    {           
        VegQuantity *vegetarian1 = [[VegQuantity alloc] initWithNibName:@"VegQuantity" bundle:nil];
        vegetarian1.pass=dict1;
        [self presentModalViewController:vegetarian1 animated:YES];
     }
}

- (void)viewDidLoad 
{
    array=[NSMutableArray array];
    dict=[NSDictionary dictionaryWithObjectsAndKeys:@"20.00",@"price",@"tomato soup",@"name",nil];
    [array addObject:dict]; 
    dict1=[NSDictionary dictionaryWithObjectsAndKeys:@"10.00",@"price",@"Veg Manchow soup",@"name",nil];
    [array addObject:dict1];
    NSLog(@"The array of dictionaries contains%@",array);
    [super viewDidLoad];
}

VegQuantity.h

NSDictionary *pass;
IBOutlet UIButton *done;
IBOutlet UITextField *input,*output;
NSNumber *prices;
float x,y,c;

VegQuantity.m

The done button just retrieves the key for that particular dish and multiplies it with the quantity user inputs in the textfield and displays it in the output textfield I am facing NSInvalidArgumentException on pass objectForKey line, what can be the problem?

-(IBAction)done:(id)sender
{   
    prices=[pass objectForKey:@"price"];
    x=[input.text floatValue];
    y=[prices floatValue];
    c=x*y;
    output.text=[NSString stringWithFormat:@"%f",c];
}

Solution 1

Change below code in viewDidLoad method.

array=[[NSMutableArray alloc]init];
dict=[[NSDictionary alloc] initWithObjectsAndKeys:@"20.00",@"price",@"tomato soup",@"name",nil];
[array addObject:dict]; 
dict1=[[NSDictionary alloc]initWithObjectsAndKeys:@"10.00",@"price",@"Veg Manchow soup",@"name",nil];
[array addObject:dict1];

Solution 2

In your case array, dict and dict1 are autoreleased objects. Retain these member variable in the viewDidLoad method. Or have a retain property to these variables. It is crashing because the dict is being released. The crash says that the variable dict is of type CFString, which might be caused due to autoreleasing of that object.