objective-c - NSDictionary 不会填满

Question

我有以下一段代码。

-(NSDictionary *)getPlayers
{

    NSManagedObjectContext *context = self.genkDatabase.managedObjectContext;

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Team"
                                              inManagedObjectContext:context];
    fetchRequest.predicate = [NSPredicate predicateWithFormat:@"position ==[c] %@", @"Doelman"];
    [fetchRequest setEntity:entity];

    NSError *error;
    NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
    if (fetchedObjects == nil) {
        // Handle the error.
    }else

        for (Team *info in fetchedObjects) {

            [_photos setObject:info.image  forKey:@"player_imgUrl"];
            [_photos setObject:info.name forKey:@"player_name"];


        }
    NSLog(@"%@",_photos);
    return _photos;

但出于某种原因，我的 NSLog 总是返回 (null)。但是当我这样做的时候

[_photos setObject:info.image  forKey:@"player_imgUrl"];
            [_photos setObject:info.name forKey:@"player_name"];

            NSLog(@"name: %@",info.name );
            NSLog(@"url: %@",info.image );

它返回正确的数据。

有人可以帮忙吗？

亲切的问候。

Answer 1

确保您已使用以下代码行在某处实例化了您的 _photos 字典:

_photos = [[NSMutableDictionary alloc] init];

仅将其定义为实例变量或属性是不够的。