//设置通知
[[NSNotificationCenter defaultCenter] addobserver:self selector:@selector(dataChanged:) name:NSManagedobjectContextDidSaveNotification object:context];
//后来
- (void)dataChanged:(NSNotification *)notification{
NSDictionary *info = notification.userInfo;
NSSet *insertedobjects = [info objectForKey:NSInsertedobjectsKey];
NSSet *deletedobjects = [info objectForKey:NSDeletedobjectsKey];
NSSet *updatedobjects = [info objectForKey:NSUpdatedobjectsKey];
有没有从更新对象确定哪些字段实际上改变？
谢谢,
迈克尔
解决方法
以下应该做的诀窍,但您将需要使用NSManagedobjectContextwillSaveNotification,并通过用于保存对象的相同的NSManagedobjectContext访问更新的对象.
for(NSManagedobject *obj in updatedobjects){
NSDictionary *changes = [obj changedValues];
// Now process the changes as you need
}
参见评论中的讨论.