iOS：不会调用委托回调

Question

问题是并不是所有的委托方法都被调用了。

登录.h

#import <Foundation/Foundation.h>
@protocol LTLoginDelegate;

@interface LTLogin : NSObject

@property(nonatomic, weak) id <LTLoginDelegate> delegate;

-(void)commitLogin:(NSString*)login password:(NSString*)password;
-(void)login:(LTLogin*)login didBecomeActive:(BOOL)success;
-(void)login:(LTLogin*)login didFailWithError:(NSError*)error;
-(void)login:(LTLogin*)login didSuccessWithMessage:(NSString*)message;

-(void)storeLoginCredentials;

@end

@protocol LTLoginDelegate <NSObject>

@optional
-(void)storeLoginCredentials;
-(void)login:(LTLogin*)login didSuccessStoringCredentials:(BOOL)success;
-(void)login:(LTLogin*)login didFailStoringCredentials:(BOOL)success;

@required
-(void)login:(LTLogin*)login didBecomeActive:(BOOL)success;
-(void)login:(LTLogin*)login didFailWithError:(NSError*)error;
-(void)login:(LTLogin*)login didSuccessWithMessage:(NSString*)message;

@end

登录.m

@implementation LTLogin

-(void)commitLogin:(NSString *)login password:(NSString *)password {

    // >>> ....
    if([self.delegate respondsToSelector:@selector(login:didBecomeActive:)]) {

        [self.delegate login:self didBecomeActive:YES];
    }
}


-(void)login:(LTLogin *)login didBecomeActive:(BOOL)success {

    // >>> ....
    // Don't get called here at all!!!!!!
    [self.delegate login:self didSuccessWithMessage:@"Success"];
}

-(void)login:(LTLogin *)login didSuccessWithMessage:(NSString *)message {


}

@end

控制器.m

-(void)viewDidAppear:(BOOL)animated {

#if LOG == 0
    NSLog(@"This one");
#endif

    LTLogin *login = [[LTLogin alloc]init];
    login.delegate = self;
    [login commitLogin:@"john.doe@hmail.con" password:@"123123"];
}

-(void)login:(LTLogin *)login didFailWithError:(NSError *)error {

#if LOG == 1
    NSLog(@"login didFailWithError: Error %@",error);
#endif

}

-(void)login:(LTLogin *)login didSuccessWithMessage:(NSString *)message {

#if LOG == 1
    NSLog(@"login didSucceedWithMessage: %@",message);
#endif

}

-(void)login:(LTLogin *)login didBecomeActive:(BOOL)success {

#if LOG == 1
    NSLog(@"login didBecomeActive");
#endif
// Gets called here only!!!!!!

}

didBecomeActive 不会在登录控制器上被调用。我的目标是构建一个相互调用的回调方法链。

Answer 1

问题在于调用者“self.delegate”到“self”。将旧版本的 commitLogin 替换为

-(void)commitLogin:(NSString *)login password:(NSString *)password {

    // >>> ....
    if([self.delegate respondsToSelector:@selector(login:didBecomeActive:)]) {

        [self login:self didBecomeActive:YES];
    }
}

Answer 2

方法-(void)login:(LTLogin *)login didBecomeActive:(BOOL)success 只会在当前委托上被调用。在-(void)viewDidAppear:(BOOL)animated 中，您将其设置为Controller。如果您想拥有多个代表，您可以使用observer pattern 或NSNotificationCenter。请记住同时添加您的控制器和 LTLogin 实例。