iphone - Undeclared identifier error when adding Core Data to existing Xcode project -

i have existing project , want use coredata.

upon creation of project, coredata.framework added under frameworks group, , under link binary libraries in project's target -> build phases. didn't check "use core data" when created project--the check box not there--it in project. use xcode version 4.6.3.

reading tutorials, went app-prefix.pch , added import coredata. looks this:

#import <availability.h>  #ifndef __iphone_5_0 #warning "this project uses features available in ios sdk 5.0 , later." #endif  #ifdef __objc__     #import <uikit/uikit.h>     #import <coredata/coredata.h>     #import <foundation/foundation.h> #endif 

then, added following in appdelegate.h:

@property (readonly, nonatomic, strong) nsmanagedobjectcontext *managedobjectcontext; @property (readonly, nonatomic, strong) nsmanagedobjectmodel *managedobjectmodel; @property (readonly, nonatomic, strong) nspersistentstorecoordinator *persistentstorecoordinator;  - (void)savecontext; 

and now, when override getter managedobjectcontext, xcode throws error:

use of undeclared identifier '_managedobjectcontext'; did mean 'nsmanagedobjectcontext'?

this getter method in appdelegate.m:

- (nsmanagedobjectcontext *)managedobjectcontext {     if(_managedobjectcontext != nil)         return _managedobjectcontext;      nspersistentstorecoordinator* psc = [self persistentstorecoordinator];      if(psc != nil)     {         _managedobjectcontext = [[nsmanagedobjectcontext alloc] init];         [_managedobjectcontext setpersistentstorecoordinator:psc];     }      return _managedobjectcontext; } 

i tried putting .pch file in copy bundle resources no avail. help?

you've set correctly (note don't need add pch copy bundle resources build phase). reason you're getting error because _managedobjectcontext ivar not getting synthesized, because you're overriding getter on read-only property. either need change property readwrite (which wouldn't recommend), redefine property readwrite in class extension, or define ivar manually in class extension or implementation block.