RKObjectManager映射结果问题

Question

我试图将来自[[RKObjectManager sharedManager] getObjectsAtPath:@"/groups" ...的结果存储在数组中，并想知道为什么数组没有将我的对象存储在getObjectsAtPath之外。

@property (strong, nonatomic) NSArray *groups;

- (void)loadGroups
{

[[RKObjectManager sharedManager]  getObjectsAtPath:@"/groups"  parameters:nil     
success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
    [self.refreshControl endRefreshing];

    self.groups = mappingResult.array;
    NSLog(@"GROUP COUNT INSIDE %@", [NSString stringWithFormat:@"%d", _groups.count]);
    NSLog(@"GROUP NAME INSIDE %@",[self.groups objectAtIndex:0]);
    NSLog(@"GROUP NAME INSIDE %@",[[self.groups objectAtIndex:0] valueForKey:@"groupName"]);
} failure:^(RKObjectRequestOperation *operation, NSError *error) {
    [self.refreshControl endRefreshing];
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"An Error Has Occurred" message:[error localizedDescription] delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alertView show];
}];

NSLog(@"GROUP NAME OUTSIDE %@",[self.groups objectAtIndex:0]);
NSLog(@"GROUP NAME OUTSIDE %@",[[self.groups objectAtIndex:0] valueForKey:@"groupName"]);
NSLog(@"GROUP COUNT OUTSIDE %@", [NSString stringWithFormat:@"%d", self.groups.count]);
}

NSLOG产出：

2013-11-10 12:04:33.281 Test[64618:11603] GROUP NAME OUTSIDE (null)
2013-11-10 12:04:33.294 Test[64618:11603] GROUP NAME OUTSIDE (null)
2013-11-10 12:04:33.345 Test[64618:11603] GROUP COUNT OUTSIDE 0
2013-11-10 12:04:33.482 Test[64618:11603] GROUP COUNT INSIDE 1
2013-11-10 12:04:33.483 Test[64618:11603] GROUP NAME INSIDE <NSManagedObject: 0x957b990> (entity: Group; id: 0x7693570 <x-coredata://174C4545-59FF-4A3A-A3B5-29520354ADD9/Group/p1> ; data: {
    groupDescription = "Admin Group";
    groupId = 1;
    groupName = Admin;
})
2013-11-10 12:04:33.484 Test[64618:11603] GROUP NAME INSIDE Admin

Answer 1

当你说“getObjectsAtPath之外”时，你指的是成功块之外。原因很简单，因为成功块还没有运行，所以您的属性还没有设置值。这是因为对getObjectsAtPath的调用是异步的，可能需要几十秒才能获得所请求的数据。在成功块被调用之前，您不应该期望数据是可用的。(调用getObjectsAtPath在线程完成之前不会阻塞它)。