Question

i am getting the following error when I load the view with my UIPickerView:

* Terminating app due to uncaught exception ‘NSInvalidArgumentException’, reason: ‘-[NSCFNumber isEqualToString:]: unrecognized selector sent to instance 0x5906000’

Here is all my code related to the picker:

-(void)viewDidLoad:
NSMutableArray * array = [[NSMutableArray alloc] initWithCapacity:700];
    for ( int i = 1 ; i <= 100 ; i ++ )
        [array addObject:[NSNumber numberWithInt:i]];
    weightArray = array;
    //[array release];

 #pragma mark - Weight Picker 
    - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView 
    {
        return 1;
    }

    - (NSInteger)pickerView:(UIPickerView *)thePickerView numberOfRowsInComponent:(NSInteger)component 
    {
        return [weightArray count];
    }

    - (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component 
    {
        return [weightArray objectAtIndex:row];
    }

    - (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component 
    {

       // NSLog(@"Selected Color: %@. Index of selected color: %i", [weightArray objectAtIndex:row], row);
    }

Update

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
    if (thePickerView.tag==1)
    {
        //float weight = [[pickerArray objectAtIndex:row] intValue];
        UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 300, 37)];
        float weight = [[pickerArray objectAtIndex:row] floatValue];
        label.text = [NSString stringWithFormat:@"%f lb", weight];
        //label.text = [NSString stringWithFormat:@"%f lb", weight];
        label.textAlignment = UITextAlignmentCenter;
        label.backgroundColor = [UIColor clearColor];
        label.font = [UIFont systemFontOfSize:30];
        [label autorelease];
        return label;
    }

    else
    {
        int reps = [[pickerArray objectAtIndex:row] intValue];
        UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 300, 37)];
        label.text = [NSString stringWithFormat:@"%d reps", reps];
        label.textAlignment = UITextAlignmentCenter;
        label.backgroundColor = [UIColor clearColor];
        label.font = [UIFont systemFontOfSize:30];
        [label autorelease];
        return label;
    }
}

Answer 1

Faisal,
I think problem lies

- (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component 
    {
        return [weightArray objectAtIndex:row];
    }

in above method… weightArray is array of NSNumber. and you are treating it as string you should rather try following

- (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component 
    {
        int weight = [[weightArray objectAtIndex:row] intValue];
        NSString *pickerTitle = [NSString stringWithFormat:@"%d",weight];
        return pickerTitle;
    }

Regarding Picker methods

 #pragma mark - Weight Picker 
    - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView 
    {
       use like this...
       if(thePickerView.tag==1)
       {
        return 1;
       }
      else if(thePickerView.tag==2)
       {
        return 2; //just for example...
       }
      else 
        return 1;
    }

    - (NSInteger)pickerView:(UIPickerView *)thePickerView numberOfRowsInComponent:(NSInteger)component 
    {
        return [weightArray count];
    }

    - (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component 
    {
        if(thePickerView.tag==1)
        {
          return [weightArray objectAtIndex:row];
        }
         else if(thePickerView.tag==1)
        {
          return ;//your other value and so on.....
        }
    }

Thanks,