Xcode 4.5 still seems to be expecting @synthesize - else cannot access property

Question

I'm using Xcode 4.5 on a brand new installation of Mountain Lion. Compiler is LLVM4.1 and my project is using ARC. (I've dabbled with Xcode in the past, but not touched it for a while).

My question:

I understand that in newer versions of Xcode it is no longer necessary to include the @synthesize directive (and sure enough, when I ctrl-drag from a UI component in the .xib to the .h file the directives don't get created in the .m file), yet without them I am unable to access those properties, and instead get the "Unknown receiver xxx" error.

Simple example:

I created a Single View iPhone project with a label ('myLabel') and a button ('myButton'). I ctrl-dragged from the UILabel in ViewController.xib to ViewController.h to create the following property:

@property (strong, nonatomic) IBOutlet UILabel *myLabel;

and I created the button action by dragging and dropping too.

In the .m file I wrote the following code in the myButton method:

- (IBAction)myButton:(id)sender {
  NSLog(@"The label text is %@", [myLabel text]);
}

Result:

This gives me a compile time error ("Unknown receiver myLabel").

I can still access my property either using an underscore (i.e. [_myLabel text]) or by adding "@synthesize myLabel;" at the top of the .m file manually, but I thought I didn't need to do this, or that it should be done for me. Can anyone explain what I am doing wrong in the code (or perhaps if this is due to some setting I need to tweak?)

Thanks

p.s. I note that my .m file now also has its own @interface block at the top (presumably for declaring private vars?)

Answer 1

Automatic ivars are prefixed with an underscore to differentiate them from property names. So you will need to use _myLabel. If you don't like the default prefix, you can change the ivar name for the property using @synthesize