iphone - NSInvalidArgumentException'，原因 : 'Unknown predicate type for predicate: BLOCKPREDICATE(0x70ad750)' Error

Question

我有一个核心数据数据库，我正在尝试使用 block 谓词创建获取请求，但我收到未知谓词错误:

NOTE: employeeToHouse is a property of type House that was created for me when I subclassed NSManagedObject

NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Place"];
request.predicate       = [NSPredicate predicateWithBlock:^BOOL(id evaluatedObject, NSDictionary *bindings) {
    Place *sortPlace            = (Place *)evaluatedObject;
    CLLocation *placeLocation   = [[CLLocation alloc] initWithLatitude:sortPlace.latitude.doubleValue 
                                                             longitude:sortPlace.longitude.doubleValue];
    CLLocationDistance distance = [placeLocation distanceFromLocation:self.userLocation];
    sortPlace.distanceToUser    = [NSNumber numberWithDouble:distance];
    if(distance<3000)
    {
        return YES;
    }
    return NO;
}];
request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@ "distanceToUser" 
                                                                                 ascending:YES 
                                                                                  selector:@selector(localizedCaseInsensitiveCompare:)]];

[self.loadingView removeSpinner];
[self setupFetchedResultsControllerWithFetchRequest:request];

然后我得到这个错误:

NSInvalidArgumentException', reason: 'Unknown predicate type for predicate: BLOCKPREDICATE(0x70ad750)'

我做错了什么吗？

Answer 1

据我所知，您不能将 block 谓词与 CoreData 一起使用。

在此处查看投票最多的答案:NSFetchRequest and predicateWithBlock

原因是 CoreData 无法将 block 中包含的 C 代码转换为 SQL 查询。