Cyclic한 import 해결(xcode unknown type name)

stackoverflow.com 참조:

요약하자면 .h에서는 @class로 선언만 해주고 .m에서 실제로 #import하라는 얘기이다.

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I got code like this: Match.h: #import <Foundation/Foundation.h> #import "player.h" @interface Match : NSObject {     Player *firstPlayer; } @property (nonatomic, retain) Player *firstPlayer; @end Player.h: #import <Foundation/Foundation.h> #import "game.h" @interface Player : NSObject { } - (Player *) init; //- (NSInteger)numberOfPoints; //- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil; @property (nonatomic, retain) NSString *name; @property (nonatomic, retain) NSString *surname; @property (nonatomic, assign) NSInteger *player_id; @property (nonatomic, retain) NSString *notes; @end Game.h: #import <Foundation/Foundation.h> #import "match.h" #import "player.h" @interface Game : NSObject {     NSMutableArray *matches;     NSMutableArray *players;     NSString *name; } -(Game *) init; @property (nonatomic, retain) NSMutableArray *matches; @property (nonatomic, retain) NSMutableArray *players; @property (nonatomic, retain) NSString *name; @end Xcode won't compile my project and show me error unknown type 'Player' in Match.h when I declare *firstPlayer. I tried cleaning project, rebuilding it but without any result... iphone objective-c ios link|edit asked Oct 26 '11 at 0:00 Esse 44928

4   You have a cycle in your imports: Match.h imports Player.h imports Game.h imports Match.h. See this question. – Bavarious Oct 26 '11 at 0:07 possible duplicate of Objective-C header file not recognizing custom object as a type – Iulius Cæsar Oct 26 '11 at 1:56 feedback

1 Answer

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up vote14down voteaccepted	The normal way to solve this cycles is to forward declare classes: In Match.h: @class Player; @interface Match ...     Player * firstPlayer; and do #import "Player.h only in Match.m, not in Match.h Same for the other two .h files. link|edit edited Oct 26 '11 at 0:57 Justin 26.5k21947 answered Oct 26 '11 at 0:53 ott-- 1,728239
	thank you - that helped :) – Esse Oct 26 '11 at 10:19