Question

我有一个对象selectedActivity定义如下：

@property (strong, nonatomic) Activities *selectedActivity;

在我需要使用它时，请注销：

{
    actname = "Running";
    aid = 23;
}

Activities对象是NSManaged对象，其.h文件如下所示。

@interface Activities : NSManagedObject

@property (nonatomic, retain) NSString * actname;
@property (nonatomic, retain) NSNumber * aid;
@end

我试图将一个对象属性放在一个变量中，使用以下代码来处理它：

 NSNumber *aid = _selectedActivity.aid;

但是，上面的行给出了以下错误消息：

[NSKnownKeysDictionary1 aid]: unrecognized selector sent to instance 0x147842fb0

任何人都可以解释这个错误以及如何修复它吗？

感谢您的任何建议。

更新：选定活动的设置

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {

     _selectedActivity =([_activities objectAtIndex:row]);
    NSLog(@"selectedActivity in pickerview%@",_selectedActivity);
}
//activities in .h file
    @property (strong, nonatomic) NSArray *activities;
//setting of activities
 self.activities= [self getActivities];

//method that gets activities
- (id) getActivities{
    NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Activities"];
     NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"created" ascending:NO];
    [fetchRequest setSortDescriptors:@[sort]];
    NSError *error      = nil;
    self.managedObjectContext = [Model sharedInstance].managedObjectContext;

    NSArray *results    = [self.managedObjectContext executeFetchRequest:fetchRequest
                                                                   error:&error];
      NSMutableArray *mutableresults = [results mutableCopy];
    [mutableresults removeObjectIdenticalTo:[NSNull null]];

    return mutableresults; 
}

Answer 1

结果将作为字典出现。

代替通常的NSManagedObject - 样式值检索：

目标C NSString *actname = _selectedActivity.actname; NSNumber *aid = _selectedActivity.aid;

夫特 let actname:String = _selectedActivity.actname let aid:Int = _selectedActivity.aid

使用 NSDictionary - 样式值检索，如下所示：

目标C ： NSString *actname = [_selectedActivity valueForKey:@"actname"]; NSNumber *aid = [[_selectedActivity valueForKey:@"aid"] intValue];

Swift（从3.0.1开始测试） _selectedActivity(forKey: "actname") as! String _selectedActivity.value(forKey: "aid") as! Int

IOS：NSKnownKeysDictionary1错误

1 个答案: