Question

1) I have the CoreData.framework imported. In Groups & Files I see it in the Framworks list together with UIKit.framework, Foundation.framework, CoreGraphics.framework.

2) I have this code, I am not sure what this error means

#import <UIKit/UIKit.h>

@interface SQLLiteDemoAppDelegate : NSObject <UIApplicationDelegate> {
   UIWindow *window;
   MyTableViewController *myTableViewController; //error on this line
}

@property (nonatomic, retain) IBOutlet UIWindow *window;

@end

MyTableViewController.h looks like this
#import <UIKit/UIKit.h>
#import <CoreData/CoreData.h>


@interface MyTableViewController : UITableViewController {
NSMutableArray *names;
}

@end

Answer 1

MyTableViewController is not declared where you’re using it so compiler can’t know how to treat that name. You have 2 options how to fix that:

1. just import the MyTableViewController.h in your SQLLiteDemoAppDelegate.h file

2. use forward declaration in your header class and import SQLLiteDemoAppDelegate.h in .m file:

   //SQLLiteDemoAppDelegate.h
   @class MyTableViewController;
   @interface SQLLiteDemoAppDelegate : NSObject <UIApplicationDelegate> {
   ...
   
   
   //SQLLiteDemoAppDelegate.m
   #import "MyTableViewController.h"
   ...