添加具有关系的实体 NSSet 后应用程序挂起/崩溃

Question

我必须解决我认为相关的主要问题，因为它们都发生在同一行代码上。

数据模型

注意：我已尽我所能简化了代码和模型。

我的核心数据模型中有 3 个实体。

• Merchant（可以有多个Branch，可以有多个Sector）
• Sector（可以有多个商家）
• 分支（可以有一个商家）

数据下载（以 JSON 格式）到应用程序。每个 Merchant 都会在提取的扇区上进行迭代，如果扇区存在，则将其提取并添加到 NSMutableArray 中。

...
//Iterating through Merchants
...
for(NSDictionary *sector in sectors) {
    NSLog(@"\tfetch sectors ID %@", [sector objectForKey:@"sector_id"]);
        
    NSPredicate *sectorPredicate = [NSPredicate predicateWithFormat:@"%K == %d", @"sectorID", [[sector objectForKey:@"sector_id"] integerValue]];
    [sectorRequest setPredicate:sectorPredicate];
                        
    NSArray *existingSector = [self.managedObjectContext executeFetchRequest:sectorRequest error:&error];
                
    if(!error && [existingSector count] == 1) {
        NSLog(@"\tfound sector");
    [merchantSectors addObject:[existingSector objectAtIndex:0]];
    }
    else {
        NSLog(@"\tcreate a new sector");
            
        //Create a new sector
        Sector *newSector = [[Sector alloc] initWithEntity:sectorEntity insertIntoManagedObjectContext:self.managedObjectContext];
        newSector.sectorID = [NSNumber numberWithInteger:[[sector objectForKey:@"sector_id"] integerValue]];
        newSector.name = [sector objectForKey:@"name"];
            
        [merchantSectors addObject:newSector];
            
        [newSector release]; newSector = nil;
    }
}
    
[sectorRequest release]; sectorRequest = nil;
    
NSLog(@"\tadd sectors to merchant");
[currentMerchant addSector:merchantSectors]; //<---- crash and hang

应用程序要么挂在：

 [currentMerchant addSector:merchantSectors];

要么有时抛出异常：

*** Terminating app due to uncaught exception \
'NSInternalInconsistencyException', reason: \ 
'-[__NSCFSet addObject:]: mutating method sent to immutable object'

Branch 解析代码几乎相同，但从来没有这些问题，或者应用程序会在成为问题之前挂起或崩溃（??）。

如果删除应用程序并重新安装代码将正常工作，是否可能是现有的相同关系导致了此问题？

编辑： JSON 的解析是使用 NSInitationOperation 调用的，因此当它挂起时，界面仍保持响应。崩溃版本会杀死该应用程序。

编辑2： Merchant.h 和 Merchant.m

Merchant.h

#import <CoreData/CoreData.h>

@class Branch;
@class Sector;

@interface Merchant :  NSManagedObject  
{
}

@property (nonatomic, retain) NSString * street;
@property (nonatomic, retain) NSString * locality;
@property (nonatomic, retain) NSString * city;
@property (nonatomic, retain) NSNumber * merchantID;
@property (nonatomic, retain) NSString * postcode;
@property (nonatomic, retain) NSString * property;
@property (nonatomic, retain) NSString * organisation;
@property (nonatomic, retain) NSDate * expires;
@property (nonatomic, retain) NSSet * Branch;
@property (nonatomic, retain) NSSet* Sector;

@end


@interface Merchant (CoreDataGeneratedAccessors)
- (void)addBranchObject:(Branch *)value;
- (void)removeBranchObject:(Branch *)value;
- (void)addBranch:(NSSet *)value;
- (void)removeBranch:(NSSet *)value;
- (void)addSectorObject:(Sector *)value;
- (void)removeSectorObject:(Sector *)value;
- (void)addSector:(NSSet *)value;
- (void)removeSector:(NSSet *)value;

@end

Merchant.m

#import "Merchant.h"
#import "Branch.h"

@implementation Merchant 

@dynamic street;
@dynamic locality;
@dynamic city;
@dynamic merchantID;
@dynamic postcode;
@dynamic property;
@dynamic organisation;
@dynamic expires;
@dynamic Branch;
@dynamic Sector;

@end

Answer 1

尝试使用 CoreData addObject: 和 removeObject: 自动生成的方法（如自定义到-许多关系访问器方法）

for(NSDictionary *sector in sectors) {
    NSPredicate *sectorPredicate = [NSPredicate predicateWithFormat:@"%K == %d", @"sectorID", [[sector objectForKey:@"sector_id"] integerValue]];
    [sectorRequest setPredicate:sectorPredicate];

    NSArray *existingSector = [self.managedObjectContext executeFetchRequest:sectorRequest error:&error];

    if(!error && [existingSector count] == 1) 
    {
        [currentMerchant addSectorObject:[existingSector lastObject]];
    }
    else 
    {
        Sector *newSector = [[Sector alloc] initWithEntity:sectorEntity insertIntoManagedObjectContext:self.managedObjectContext];
        newSector.sectorID = [NSNumber numberWithInteger:[[sector objectForKey:@"sector_id"] integerValue]];
        newSector.name = [sector objectForKey:@"name"];

        [currentMerchant addSectorObject:newSector];

        [newSector release];
    }
}

或者您可以通过mutableSetValueForKey：检索包含当前商家扇区的可变代理对象并向其添加扇区：

NSMutableSet *merchantSectors = [currentMerchant mutableSetValueForKey:@"sector"];
for(NSDictionary *sector in sectors) {
    NSPredicate *sectorPredicate = [NSPredicate predicateWithFormat:@"%K == %d", @"sectorID", [[sector objectForKey:@"sector_id"] integerValue]];
    [sectorRequest setPredicate:sectorPredicate];

    NSArray *existingSector = [self.managedObjectContext executeFetchRequest:sectorRequest error:&error];

    if(!error && [existingSector count] == 1) 
    {
        [merchantSectors addObject:[existingSector lastObject]];
    }
    else 
    {
        Sector *newSector = [[Sector alloc] initWithEntity:sectorEntity insertIntoManagedObjectContext:self.managedObjectContext];
        newSector.sectorID = [NSNumber numberWithInteger:[[sector objectForKey:@"sector_id"] integerValue]];
        newSector.name = [sector objectForKey:@"name"];

        [merchantSectors addObject:newSector];

        [newSector release];
    }
}

无论如何，为了方便起见，最好使用小写sectors< /code> Mecrhant 实体的名称，用于与 Sector 实体的一对多关系：小写，以免与 Sector 类名和 s 混淆，并且可以肯定的是，该属性的 getter 方法返回多个对象。