Question

In WebServiceAPI.h, which I referred in the code below, i declared a protocol with a required metod -(void) apiFinished:(WebServiceAPI *)api. When compiling the code i get this error: WebServiceAPI.h:13: error: expected ‘)’ before ‘WebServiceAPI’ (line 13 is where the method of the protocol is declared). where am I doing wrong?

#import <Foundation/Foundation.h>
@protocol WebServiceAPIDelegate
@required
    -(void) apiFinished:(WebServiceAPI *)api;
@end

@interface WebServiceAPI : NSObject{
    NSString *address;
    NSMutableData *dataWebService;
}

@property (nonatomic, assign) id <WebServiceAPIDelegate>delegate;
@property(nonatomic, retain) NSString *address;
@property(nonatomic, retain) NSMutableData *dataWebService;
@end

Answer 1

The problem is that WebServiceAPIDelegate doesn’t know about the class WebServiceAPI when it is defined. Add a @class directive before you create WebServiceAPIDelegate @protocol declaration.

// Add the following line to let the compiler stop worrying about 
// the existance of class WebServiceAPI

@class WebServiceAPI;

@protocol WebServiceAPIDelegate
@required
    -(void) apiFinished:(WebServiceAPI *)api;
@end