Can't compile code when working with CALayer

Question

For some reason I get linker errors when I try and use CALayer:

  "_OBJC_CLASS_$_CALayer", referenced from:

I have imported the following headers:

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>

Code:

arrowImage = [[CALayer alloc] init];

Solution

Make sure you also add the QuartzCore framework to your target. Just importing the header isn't enough.

XCode Screenshot

Comments

[Simon Epskamp]

If you dont know how to do this: * right-click on you project in the Groups & Files window (on the left) * click add -> existing frameworks * select QuartzCore.framework & click Add

[Tustin2121]

Update for XCode 4: to do this, click your project in the project navigator, in the summary tab, scroll down to Linked Frameworks, and add it there. You'll have to organize the added framework in your project navigator afterwards. :)

[DrMickeyLauer]

or just @import QuartzCore;, if you are using the new Objective-C module support.