Why does the compiler say I haven't declared my variable?

Question

Hello all,

I am getting an error in Xcode that says "whatEverVariable is undeclared" This is happening inside the .m file and also outside of the class itself. I have declared the variable inside the curly braces of the .h file and am using @property and @synthesize to access the variable. However I am getting that above error in the .m file sometimes and even in other classes where I have #imported the class that contains the variable. Am I missing something about Objective-C in general here or what? I guess what I am asking is why would things be undeclared if they are declared.

Also I am getting "button may not respond to "setTitle" as an error as well has this been deprecated or something to "setTitle: forState:" because I am not wanting to use that.

I would post an example but I really think I am missing some obvious thing here. Does anyone have any thoughts on what would cause the errors? Sorry to be so general, but I have to be a moron or something?

This is saying "picturesInArray is undeclared"

#import <Foundation/Foundation.h> 
@interface Pictures : NSObject { 
    NSMutableArray *picturesInArray; 
} 

@property (nonatomic, retain) NSMutableArray *picturesInArray; 

-(IBAction)pictureButtonPressed:(id)sender; 

@end 


#import "Pictures.h" 
@implementation Pictures 

@synthesize picturesInArray; 

-(IBAction)pictureButtonPressed:(id)sender { 

    if (pictureIndex >= [picturesInArray count] || pictureIndex < 0) { 
        pictureIndex = 0;    

        [imageView setImage:[picturesInArray objectAtIndex:pictureIndex]]; 

        [imageView setNeedsDisplay]; 
    }    
}

Answer 1

Could you post the sample code?

My guess is that you aren't declaring the object/variable type that whatEverVariable is at some point. Make sure that your header looks like this:

MyClass.h:

@interface MyClass : NSObject 
{
    NSString* whatEverVariable;
}

@property(readwrite, assign) NSString* whatEverVariable;

@end

MyClass.m:

@implementation MyClass

//whatever methods

@synthesize whatEverVariable;

@end

Notice that in your @property you are declaring the type of the variable again.

As for the button, make sure that it is of type NSButton.

Also, have you imported ? That imports a lot of the headers for things like NSButton.

Answer 2

This is saying "picturesInArray is undeclared" Sorry about putting it in "comments above it made it hard to read!

#import <Foundation/Foundation.h> 
@interface Pictures : NSObject { 
    NSMutableArray *picturesInArray; 
} 

@property (nonatomic, retain) NSMutableArray *picturesInArray; 

-(IBAction)pictureButtonPressed:(id)sender; 

@end 


#import "Pictures.h" 
@implementation Pictures 

@synthesize picturesInArray; 

-(IBAction)pictureButtonPressed:(id)sender { 

    if (pictureIndex >= [picturesInArray count] || pictureIndex < 0) { 
        pictureIndex = 0;    

        [imageView setImage:[picturesInArray objectAtIndex:pictureIndex]]; 

        [imageView setNeedsDisplay]; 
    }    
}

Answer 3

This is saying "picturesInArray is undeclared"

Are you sure it's not saying “pictureIndex is undeclared”? Because that's the variable that's undeclared in the code you showed.