代表爲NULL

Question

我有一個表格視圖從哪裏發送請求的數據從網址。我能夠獲取數據，但我想用委託將數據發送回表視圖。

問題是，當我給你我的self.delegate它包含一個值，但是當我試圖發回數據self.delegate變成000000。

在viewcontroller.m

GNRequestManager *request = [[GNRequestManager alloc]initWithDelegate:self]; 

在GNRequestManager.h

#import <Foundation/Foundation.h> 
#import "GNDownloadManager.h" 

@protocol RequestManagerDelegate <NSObject> 

- (void)didReceiveData:(NSMutableArray *)data; 

@end 


@interface GNRequestManager : NSObject 

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

-(id)initWithDelegate:(id<RequestManagerDelegate>)inDelegate; 

- (void)requestWithURL:(NSString *)urlString; 

-(void)didReceiveResponse:(NSMutableArray *)downloadData; 



@end 

在GNRequestManager.m

-(id)initWithDelegate:(id<RequestManagerDelegate>)inDelegate 
{ 
    self = [super init]; 

    if (self) 
    { 
     self.delegate = inDelegate; // **self.delegate has a value** 

    } 

    return self; 
} 



- (void)didReceiveResponse:(NSMutableArray *)downloadData // Fetch the data in downloadData 

{ 

    if(!itemArray) 
    { 
     itemArray = [[NSMutableArray alloc]init]; 
    } 

    itemArray = downloadData; 

    [self.delegate didReceiveData:itemArray]; // **self.delegate does not contain any value** 

} 

Answer 1

我曾經有過這個問題。據我所知，您將delegate作爲weak修飾符的屬性進行存儲。這意味着您的GNRequestManager不會增加您的委託對象的引用計數。 如果要創建委託對象，如：

GNDelegateObject *delegate = [GNDelegateObject new]; 
GNRequestManager *manager = [[GNRequestManager alloc] initWithDelegate:delegate]; 

委託對象將被釋放。

您應該在其他地方（不在GNRequestManager中）強烈引用您的委託對象。

UPD：你已經更新的問題，該委託設置，如：

GNRequestManager *request = [[GNRequestManager alloc]initWithDelegate:self]; 

其中self是UIViewController子類的實例。

此視圖控制器仍然在視圖控制器層次結構中嗎？也許，你已經解散/彈出它，以便它現在被釋放？