在覈心數據中傳遞對象

我是IOS編程的新手，並構建了我的核心數據概念。遵循蘋果文檔中的指導原則。我有一個表視圖控制器和一個可變數組StocksArray，作爲它的一個屬性。我有另一個視圖DetailedController，它用於獲取用戶輸入的核心數據模型的實體屬性。我將NSManagedObject傳遞給DetailedController對象並使用委託來更新可變數組StocksArray。在編譯時，出現錯誤---由於未捕獲異常'NSInvalidArgumentException'而終止應用程序，原因：'* - [NSMutableArray insertObject：atIndex：]：試圖在0處插入nil對象。如果有人能幫助我，我會很感激。在覈心數據中傳遞對象

#import"StockEntity.h" 
@protocol DetailedControllerdelegate <NSObject> 

-(void)addstockinarray:(StockEntity*)anObject; 

@end 



@interface DetailedController : UIViewController { 

IBOutlet UITextField* stocksymboltextfield; 
IBOutlet UITextField* stocknametextfield; 

//NSManagedObjectContext* context2; 

StockEntity* asinglestock; 

} 
@property (nonatomic, retain) IBOutlet UITextField* stocksymboltextfield; 
@property (nonatomic, retain) IBOutlet UITextField* stocknametextfield; 
//@property(nonatomic, retain) NSManagedObjectContext* context2; 
@property(nonatomic, retain) StockEntity* asinglestock; 
@property (nonatomic, assign) id <DetailedControllerdelegate> delegate; 

@implementation DetailedController 

@synthesize stocksymboltextfield, stocknametextfield,asinglestock, delegate;//context2; 

-(void)onDone:(id)sender{ 
[asinglestock setStockName:self.stocknametextfield.text]; 
[asinglestock setStockSymbol:self.stocksymboltextfield.text]; 

NSLog(@"lets s see: %@", [asinglestock StockName]); 
NSError *error = nil; 

if (![[asinglestock managedObjectContext] save:&error]) { 
    //handle the error 
} 


if ([delegate respondsToSelector:@selector(addstockinarray:)]) { 

    NSLog(@"before delegate"); 

    [delegate addstockinarray:asinglestock]; 

    NSLog(@"am in delegate"); 

} 


[self.navigationController popViewControllerAnimated:YES]; 

}

這是表視圖

@implementation maintable 

@synthesize stocksArray, managedObjectContext, addButton; 

- (id)initWithStyle:(UITableViewStyle)style { 
self = [super initWithStyle:style]; 
if (self) { 
    // Custom initialization. 

    self.stocksArray =[[NSMutableArray alloc]init]; 
} 
return self; 
} 

- (void)viewDidLoad { 
[super viewDidLoad]; 

//self.stocksArray =[[NSMutableArray alloc]init]; 
self.title = @"Stocks"; 

// Uncomment the following line to display an Edit button in the navigation bar for this view controller. 
self.navigationItem.leftBarButtonItem = self.editButtonItem; 

addButton = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemAdd 
                 target:self 
                 action:@selector(addStock)]; 
//addButton.enabled = NO; 
self.navigationItem.rightBarButtonItem = addButton; 
} 


-(void) addStock{ 

DetailedController *detail = [[DetailedController alloc]initWithNibName:NSStringFromClass([DetailedController class]) bundle:[NSBundle mainBundle]]; 
//detail.context2 = managedObjectContext; 
StockEntity *stock = (StockEntity*)[NSEntityDescription insertNewObjectForEntityForName:@"StockEntity" 
                   inManagedObjectContext:managedObjectContext]; 

detail.asinglestock = stock; 
detail.delegate = self; 

//[stocksArray insertObject:stock atIndex:0]; 


[self.navigationController pushViewController:detail animated:YES]; 

[detail release]; 



} 

-(void)addstockinarray:(StockEntity*)anObject{ 

if (anObject = NULL) { 
    NSLog(@"YESSS"); 
} 
[self.stocksArray addObject:anObject]; 

NSLog(@"LETTTTTT: %i", [self.stocksArray count]); 

} 




- (void)viewWillAppear:(BOOL)animated { 

[self.tableView reloadData]; 
[super viewWillAppear:animated]; 
}

來源

2012-11-29 user1443613

嘗試使用此方法處理墜毀的實施，

- (void)addstockinarray:(StockEntity*)anObject{ 

    if (anObject) { 
    [self.stocksArray addObject:anObject]; 
    } else { 
    NSLog(@"Object is nil, do the error handling here"); 
    } 

    NSLog(@"LETTTTTT: %i", [self.stocksArray count]); 
}

你的問題是，你正在試圖插入，零值陣列。你應該檢查爲什麼anObject是零，並修復它。如果我是正確的，asinglestock不知何故爲零，你試圖插入。

來源

2012-11-29 06:05:25 iDev

在覈心數據中傳遞對象

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