解決編譯器中的警告：發送'BarCodeViewController * _strong'到不兼容類型的參數'id <PerksDetailsDelegate>'

Question

我有2個視圖控制器，PerksDetailsViewController和BarcodeViewController。我使用代表團將一個Card類和從PerksDetailsVC中獲得的點數傳遞給BarcodeVC。

我的應用程序的作品，但是我想擺脫這種警告：Sending 'BarCodeViewController *_strong' to parameter of incompatible type 'id<PerksDetailsDelegate>'

這是從線[self setDelegate:barCodeVC];

方法

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender 
{ 
    if ([segue.identifier isEqualToString:@"showBarCode"]) { 
     BarcodeViewController *barCodeVC = (BarcodeViewController *)segue.destinationViewController; 

     [self setDelegate:barCodeVC]; 

    } 
} 

下面裏面是一些代碼，可以有助於發現錯誤的部分

PerksDetailsViewController.m

#import Card.h 
#import PerksDetailsViewController.h 
#import BarcodeViewController.h 

@interface PerksDetailsViewController() 

@end 

@implementation 
@synthesize delegate = _delegate; 
@synthesize myCard = _myCard; 

- (IBAction)redeemPressed:(id)sender { 
    // get required points of a perk selected 

    NSNumberFormatter * f = [[NSNumberFormatter alloc] init]; 
    [f setNumberStyle:NSNumberFormatterDecimalStyle]; 

    self.pointsRequired = [f numberFromString: (self.pointsLabel.text)]; 

    NSLog(@"points required by the perk %@", self.pointsRequired); 

    [self.delegate perksDetailsViewController:self didPassRequiredPoints:self.pointsRequired withCard:self.myCard]; 
} 


- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender 
{ 
    if ([segue.identifier isEqualToString:@"showBarCode"]) { 
     BarcodeViewController *barCodeVC = (BarcodeViewController *)segue.destinationViewController; 

     [self setDelegate:barCodeVC]; 

    } 
} 

@end 

PerksDetailsViewController.h

#import <UIKit/UIKit.h> 
#import "Card.h" 
#import "BarcodeViewController.h" 

@class PerksDetailsViewController; 

@protocol PerksDetailsDelegate <NSObject> 

- (void)perksDetailsViewController:(PerksDetailsViewController *)sender 
      didPassRequiredPoints: (NSNumber *) requiredPoints 
          withCard: (Card *) selectedCard; 

@end 

@interface PerksDetailsViewController : UIViewController 

@property (nonatomic, strong) id <PerksDetailsDelegate> delegate; 

@property (nonatomic, strong) Card *myCard; 

@end 

BarcodeViewController.m

#import "PerksDetailsViewController.h" 

@interface BarcodeViewController() <PerksDetailsDelegate> 
@end 

@implementation BarcodeViewController 
@synthesize myCard = _myCard; 
@synthesize resultingPoints = _resultingPoints; 

- (void)perksDetailsViewController:(PerksDetailsViewController *)sender didPassRequiredPoints:(NSNumber *)requiredPoints withCard:(Card *)selectedCard 
{ 

    double perksPoints = [requiredPoints doubleValue]; 

     self.myCard = selectedCard; 
     self.resultingPoints = [NSNumber numberWithDouble:[selectedCard subtractPoints:perksPoints] ]; 
} 

@end 

Answer 1

在你的.h實現BarCodeViewController你需要告訴你實現協議的編譯器。

@interface BarCodeViewController : UIViewController <PerksDetailsDelegate> { 
... 
}