Question

我必须解决我认为相关的主要问题，因为它们都出现在同一行代码中。

数据模型

注意：我尽可能地简化了代码和模型。

我的Core数据模型中有3个实体。

Merchant（可以有多个Branch es，可以有很多Sector s）
Sector（可以有多个Merchant s）
Branch（可以有一个Merchant）

将数据（以JSON格式）下载到应用程序。每个Merchant在扇区被迭代后被提取，如果扇区存在则将其提取并添加到NSMutableArray。

...
//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

该应用程序将挂起：

 [currentMerchant addSector:merchantSectors];

或有时会抛出异常：

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

Branch解析代码几乎完全相同但从未出现过这些问题，或者应用程序在成为问题之前会挂起或崩溃（??）。

如果应用程序被删除并重新安装，代码将正常工作，现有的相同关系是否可能导致此问题？

编辑：使用NSInvocationOperation调用JSON的解析，因此当它挂起时，界面保持响应。崩溃版本会杀死应用程序。

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 add<Key>Object:和remove<Key>Object:自动生成的方法（如Custom To-Many Relationship Accessor Methods中所述）逐个添加部门到商家

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currentMerchants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Mecrhant实体的小写sectors名称与Sector实体的多对多关系：小写不要与Sector类名不明确，并且使用s at和to请确保，此属性的getter方法返回多个对象。

在添加具有关系的实体的NSSet之后应用程序挂起/崩溃

数据模型

Merchant.h

Merchant.m

1 个答案: