的NSMutableSet不添加对象

Question

我的代码不添加元素我的集合。

我的头文件如下：

#import <UIKit/UIKit.h> 

@interface NHPSearchViewController : UITableViewController 
//For using the local DB 
@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext; 
//texst field where user enters a substance name or a drug name 
@property (weak, nonatomic) IBOutlet UITextField *substanceTextField; 

//An array for Drug Names, and another array for NHPs 
@property (strong, nonatomic) NSMutableSet *drugList; 
@property (strong, nonatomic) NSMutableSet *NHPList; 
//Contains both drugList and NHP list as one array for the data to be shown for the user. 
@property (strong, nonatomic) NSMutableSet *usersList; 

@end 

我.m文件：

@interface NHPSearchViewController() 
- (BOOL) checkAndAddToList: (NSString *) substance; 
@end 

@implementation NHPSearchViewController 

@synthesize managedObjectContext; 
@synthesize substanceTextField; 
@synthesize drugList, NHPList, usersList; 

//"Private" helper methods 

-(BOOL) checkAndAddToList:(NSString *)substance{ 
    // Set up a predicate for testing if the data exists in the table 
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"name == %@", substance];  

    //Run the query to see if the substance is in the Substances Table. 
    NSMutableArray *results =[NSMutableArray array]; 
    results = [CoreDataHelper searchObjectsForEntity:@"Substances" withPredicate:pred andSortKey:nil andSortAscending:NO andContext:self.managedObjectContext]; 

     if ([results count] > 0){ 
     //Found the substance return YES 
      Substances *sub = [results objectAtIndex:0];   
      NSLog(@"Did find a result with name:%@ and class_name as:%@ ",[sub name], [sub class_name]); 

      //add the name to the appropriate lists. 
      if([[sub class_name] isEqualToString:@"NHP"]){ 
       NSLog(@"NHP was found adding it to the nhp list"); 
       [NHPList addObject:[sub name]]; //THIS is not working 
       NSLog(@"NHP count after adding %i", [NHPList count]); 
      }else if ([[sub class_name] isEqualToString:@"Drugs"]){ 
       NSLog(@"Drug was found adding it to the drug list"); 
       [drugList addObject:[sub name]]; //THIS is also not working 
      } 

      //add the name to our list in the view 
      [usersList addObject:[sub name]]; //This is also not working 

      return YES; 
    }else{ 
     // 
     return YES; 

    } 
return NO; 
} 

日志输出：

[4187：FB03]测试substanceTextField值：欧米茄3-6-9 [4187：FB03] 确实发现与名称的结果是：欧米茄3-6-9和CLASS_NAME为：NHP [4187：FB03 ] NHP被发现将其添加到列表NHP [4187：FB03] NHP 计数加0 [4187后：FB03] NHP列表：0 DrugList：0的UserList：0

Answer 1

在某些时候你使用集之前，你需要创建一个新的NSMutableSet。

为了方便，你可以使用类似下面的自动分配一个新的可变集，当你问到使用它的第一次。

- (NSMutableSet *)NHPList { 
    if (NHPList == nil) { 
     NHPList = [[NSMutableSet alloc] init]; 
    } 
    return NHPList; 
} 

你也必须通过设置NHPList到nil释放内存，通常在你的viewDidUnload方法。

如果这是您所设置的数据的唯一的地方，你也可以只改变这一行：

[NHPList addObject:[sub name]]; 

到：

if (self.NHPList == nil) { 
    self.NHPList = [[NSMutableSet alloc] init]; 
} 
[self.NHPList addObject:[sub name]]; 

Answer 2

你有初始化NHPList？