Use of undeclared identifier - objective-c

Question

Am trying to configure a two component picker, and am getting some errors which I have commented out:
Implementation file:
#import "BIDDoubleComponentPickerViewController.h"
#implementation BIDDoubleComponentPickerViewController
#synthesize doublePicker;
#synthesize fillingTypes;
#synthesize breadTypes;
- (IBAction)buttonPressed:(id)sender
{
NSInteger fillingRow = [doublePicker selectedRowInComponent:kFillingComponent]; // Use of undeclared identifier 'kFillingComponent'
NSInteger breadRow = [doublePicker selectedRowInComponent:kBreadComponent]; // Use of undeclared identifier 'kBreadComponent'
NSString *bread = [breadTypes objectAtIndex:breadRow];
NSString *filling = [fillingTypes objectAtIndex:fillingRow];
NSString *message = [[NSString alloc]initWithFormat:#"Your %# on %# bread will be right up", filling, bread];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Thank you for your order"
message:message
delegate:nil
cancelButtonTitle:#"Great!"
otherButtonTitles:nil];
[alert show];
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
NSArray *fillingArray = [[NSArray alloc] initWithObjects:#"Ham", #"Turkey", #"Peanut Butter", #"Tuna Salad", #"Chicken Salad", #"Roast Beef", #"Vegemite", nil];
self.fillingTypes = fillingArray;
NSArray *breadArray = [[NSArray alloc] initWithObjects:#"White", #"Whole Wheat", #"Rye", #"Sourdough Bread", #"Seven Grain", nil];
self.breadTypes = breadArray;
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
self.doublePicker = nil;
self.breadTypes = nil;
self.fillingTypes = nil;
}
#pragma mark - View lifecycle
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
#pragma mark -
#pragma mark Picker Data Source Methods
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if (component == kBreadComponent) { // Use of undeclared identifier 'kBreadComponent'
return [self.breadTypes.count]; // Expected identifier
return [self.fillingTypes objectAtIndex:row]; // Use of undeclared identifier 'row'
}
}
#pragma mark Picker Delegate Methods
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if (component == kBreadComponent) { // Use of undeclared identifier 'kBreadComponent'
return [self.breadTypes objectAtIndex:row];
return [self.fillingTypes objectAtIndex:row];
}
}
#end
Interface file:
#import <UIKit/UIKit.h>
#interface BIDDoubleComponentPickerViewController : UIViewController
<UIPickerViewDelegate, UIPickerViewDataSource>
#property (strong, nonatomic) IBOutlet UIPickerView *doublePicker;
#property (strong, nonatomic) NSArray *fillingTypes;
#property (strong, nonatomic) NSArray *breadTypes;
- (IBAction)buttonPressed:(id)sender;
#end

Answer 1

kBreadComponent and kFillingComponent are not declared anywhere. If they're declared in a header (.h) file, you need to #import it.

Answer 2

Your numberOfRowsInComponent and titleForRow methods are similar, and they are wrong: they have two consequent unconditional return, and this means that the second one will never be executed.
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return self.breadTypes.count;
}
#pragma mark Picker Delegate Methods
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if (component == kBreadComponent) {
return [self.fillingTypes objectAtIndex:row];
}
return nil; // Or something, empty string for example. Method requires to return a NSString, so you have to return at least nil;
}
Still you have to find kBreadComponent and kFillingComponent and #import the file with the definitions of them.