How to use NSMutableDictionary in an UIAlertView?

Question

I am making a calorie counter and I have created an UIAlertView which gives me list of food items. I have made a NSMutableDictionary containing the food and the calories:

@implementation FoodDatabase

-(id)init 
{    
  self = [super init];
  if(self) 
  {
    food= [[NSMutableDictionary alloc] init];
    [food setObject:@"111" forKey:@"Rice"];       
  }
  return self;
}


-(NSString *) foodList: (NSString *) foodItem 
{
    for(NSString *key in [food allKeys]) 
    {        
        if([foodItem isEqual: key]) 
        {
            NSLog(@"%@",foodItem);
            return [food objectForKey:foodItem];
        }
    }
 }


@end

In another class, I have created an UIAlertView which gives a list of food items. This is the code snippet for the item Rice:

NSString *buttonTitle = [alertView buttonTitleAtIndex:buttonIndex];
if([buttonTitle isEqualToString:@"Rice"])
{        
    NSString *xyz = [foodData foodList: @"Rice"];
    food_calorie = ([xyz floatValue]);

    UIAlertView *rice_alert=[[UIAlertView alloc] initWithTitle:@"Enter quantity of rice consumed" message:@"100 gms = 111 calories" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Ok", nil];

    [rice_alert addTextFieldWithValue:@"" label:@"Enter quantity in gms"];

    RiceText = [rice_alert textFieldAtIndex:0];
    RiceText.keyboardType = UIKeyboardTypeNumberPad;
    RiceText.clearsOnBeginEditing = YES;
    RiceText.clearButtonMode = UITextFieldViewModeWhileEditing;
    RiceText.keyboardAppearance = UIKeyboardAppearanceAlert;
    rice_alert.tag = RiceAlertView;

    [rice_alert show];
    [rice_alert release];

}

I calculate the total calories by using the value entered by the user in the _RiceText_ and the value of the _object_ returned for a specific key (in this case rice). But it seems not to be returning the value of the _object_ as the NSLog shows _(null)_ for the value of _xyz_. Where am I going wrong??

Answer 1

The whole error is that the object foodData isn't initialized properly. So, initialize it

A nice documentation - https://developer.apple.com/library/ios/documentation/cocoa/reference/foundation/Classes/NSObject_Class/Reference/Reference.html

& fetching data from NSmutableDictionary

https://developer.apple.com/library/ios/documentation/cocoa/reference/foundation/Classes/NSDictionary_Class/Reference/Reference.html#//apple_ref/occ/instm/NSDictionary/objectForKey:

Remember the key that you use to compare in dictionary should have same casing (capital - small) as defined earlier. e.g You store an object for key 'example' but you can not retrieve it using ''Example' or 'EXAMPLE'. You can only use 'example' as defined earlier. And

---

You don't need to get arrays of keys from dictionary & fast-enumerate it

You can just get the object using objectForKey: method. Good luck.