在我的Lion应用中，我有这样的数据模型:
Item内的关系子项是有序的。
Xcode 4.1 (build 4B110)为我创建了文件Item.h, Item.h。m, SubItem.h和SubItem.h。
下面是Item.h的内容(自动生成):
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
@class SubItem;
@interface Item : NSManagedObject {
@private
}
@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) NSOrderedSet *subitems;
@end
@interface Item (CoreDataGeneratedAccessors)
- (void)insertObject:(SubItem *)value inSubitemsAtIndex:(NSUInteger)idx;
- (void)removeObjectFromSubitemsAtIndex:(NSUInteger)idx;
- (void)insertSubitems:(NSArray *)value atIndexes:(NSIndexSet *)indexes;
- (void)removeSubitemsAtIndexes:(NSIndexSet *)indexes;
- (void)replaceObjectInSubitemsAtIndex:(NSUInteger)idx withObject:(SubItem *)value;
- (void)replaceSubitemsAtIndexes:(NSIndexSet *)indexes withSubitems:(NSArray *)values;
- (void)addSubitemsObject:(SubItem *)value;
- (void)removeSubitemsObject:(SubItem *)value;
- (void)addSubitems:(NSOrderedSet *)values;
- (void)removeSubitems:(NSOrderedSet *)values;
@end
下面是Item.m的内容(自动生成):
#import "Item.h"
#import "SubItem.h"
@implementation Item
@dynamic name;
@dynamic subitems;
@end
如您所见，Item类提供了一个名为addSubitemsObject:的方法。不幸的是，当你试图以这种方式使用它时:
Item *item = [NSEntityDescription insertNewObjectForEntityForName:@"Item" inManagedObjectContext:self.managedObjectContext];
item.name = @"FirstItem";
SubItem *subItem = [NSEntityDescription insertNewObjectForEntityForName:@"SubItem" inManagedObjectContext:self.managedObjectContext];
[item addSubitemsObject:subItem];
出现以下错误:
2011-09-12 10:28:45.236 Test[2002:707] *** -[NSSet intersectsSet:]: set argument is not an NSSet
你能帮我吗?
更新:
在我的错误报告刚刚过去1787天之后，今天(2016年8月1日)，苹果公司给我写了这样的话:“请用最新的iOS 10测试版验证这个问题，并在bugreport.apple.com上更新你的错误报告。”让我们希望这是正确的时间:)
我已经找到窃听器了。它发生在willChangeValueForKey:withSetMutation:usingObjects:中。
这个呼叫会触发一连串的通知，可能很难追踪，当然，一个回复者的变化可能会影响到另一个，我怀疑这就是为什么苹果什么都没做的原因。
然而，这在Set中是可以的，只有OrderedSet上的Set操作会发生故障。这意味着只有四个方法需要修改。因此，我所做的只是将Set操作转换为等效的Array操作。这些工作非常完美，开销最小(但必要)。
On a critical level, this solution does suffer from one critical flaw; if you are adding objects and one of the objects already exists, then it is either not added or moved to the back of the ordered list (I don't know which). In either case, the expected ordered index of the object by the time we arrive at didChange is different from what was anticipated. This may break some people's apps, but it doesn't affect mine, since I am only ever adding new objects or I confirm their final locations before I add them.
- (void)addChildrenObject:(BAFinancialItem *)value {
if ([self.children containsObject:value]) {
return;
}
NSIndexSet * indexSet = [NSIndexSet indexSetWithIndex:self.children.count];
[self willChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
[[self primitiveValueForKey:ChildrenKey] addObject:value];
[self didChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
}
- (void)removeChildrenObject:(BAFinancialItem *)value {
if (![self.children containsObject:value]) {
return;
}
NSIndexSet * indexSet = [NSIndexSet indexSetWithIndex:[self.children indexOfObject:value]];
[self willChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
[[self primitiveValueForKey:ChildrenKey] removeObject:value];
[self didChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
}
- (void)addChildren:(NSOrderedSet *)values {
if ([values isSubsetOfOrderedSet:self.children]) {
return;
}
NSIndexSet * indexSet = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(self.children.count, values.count)];
[self willChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
[[self primitiveValueForKey:ChildrenKey] unionOrderedSet:values];
[self didChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
}
- (void)removeChildren:(NSOrderedSet *)values {
if (![self.children intersectsOrderedSet:values]) {
return;
}
NSIndexSet * indexSet = [self.children indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
return [values containsObject:obj];
}];
[self willChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
[[self primitiveValueForKey:ChildrenKey] minusOrderedSet:values];
[self didChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
}
当然，还有一个更简单的解决方案。内容如下;
- (void)addChildrenObject:(BAFinancialItem *)value {
if ([self.children containsObject:value]) {
return;
}
[self insertObject:value inChildrenAtIndex:self.children.count];
}
- (void)removeChildrenObject:(BAFinancialItem *)value {
if (![self.children containsObject:value]) {
return;
}
[self removeObjectFromChildrenAtIndex:[self.children indexOfObject:value]];
}
- (void)addChildren:(NSOrderedSet *)values {
if ([values isSubsetOfOrderedSet:self.children]) {
return;
}
[self insertChildren:values atIndexes:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(self.children.count, values.count)]];
}
- (void)removeChildren:(NSOrderedSet *)values {
if (![self.children intersectsOrderedSet:values]) {
return;
}
[self removeChildrenAtIndexes:[self.children indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
return [values containsObject:obj];
}]];
}
