＆＃39; NSInvalidArgumentException＆＃39;，原因：＆＃39; - [__ NSSetI getDataInBackgroundWithBlock：]

Question

请帮我学校项目，目前我想从数据库中检索一组记录并根据他们的类别显示记录。 我是IOS编程的新手，所以请帮助我。 如果可能的话请向我解释一下我的错误和可能的解决办法。 抱歉粗鲁，我需要解决方案尽快解决，因为我还需要在项目的其他部分工作。

LocationListTableViewController.m

#import "LocationListTableViewController.h"
#import <Parse/Parse.h>

@interface LocationListTableViewController ()
@property (strong, nonatomic) IBOutlet UITableView *testView;

@end

@implementation LocationListTableViewController {
    NSArray *storeLocation;
    NSMutableDictionary *categoriesDict;
    NSString *checkValue;
}

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    PFQuery *query = [PFQuery queryWithClassName:@"GPS"];
    // pulling everything
    UIActivityIndicatorView *ai = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
    ai.center = self.view.center;
    [ai startAnimating];
    [self.view addSubview:ai];
    storeLocation = [query findObjects];
    [ai stopAnimating];
    [self.tableView reloadData];

    categoriesDict = [[NSMutableDictionary alloc]init];
    for (NSDictionary *locationCat in storeLocation) {
        NSString *stringLocation = [locationCat objectForKey:@"locationCategory"];
        NSMutableSet *categoriesSet = [categoriesDict objectForKey:stringLocation];
        if (!categoriesSet)
        {
            categoriesSet = [NSMutableSet set];
            [categoriesDict setObject:categoriesSet forKey:[locationCat objectForKey:@"locationCategory"]];
        }
        [categoriesSet addObject:locationCat];

//        NSLog(@"categroesDict value are %d", [[categoriesDict objectForKey:@"All"] count]);
//        NSLog(@"categroesDict value are %@", [categoriesDict objectForKey:@"test"]);
    };





}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Table view data source

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [[categoriesDict objectForKey:checkValue] count];
}


-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    static NSString *simpleid = @"Location";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:simpleid];

    if (cell == nil)
    {
        cell = [[UITableViewCell alloc]
                 initWithStyle:UITableViewCellStyleDefault
                 reuseIdentifier:simpleid];
    }

//    NSLog(@"categoriesDict objectForKey:checkValue ---- %@", [categoriesDict objectForKey:checkValue]);
//    NSLog(@"categoriesDict objectForKey:checkValue valueForKey ---- %@", [[categoriesDict objectForKey:checkValue]valueForKey:@"locationCategory"]);
//    NSLog(@"categoriesDict objectForKey:checkValue valueForKey ---- %@", [[categoriesDict objectForKey:checkValue]valueForKey:@"locationName"]);

        UILabel *locationLabel = (UILabel *)[cell viewWithTag:100];
        locationLabel.text = [[categoriesDict objectForKey:checkValue]valueForKey:@"locationName"];

        UILabel *addressLabel = (UILabel *)[cell viewWithTag:101];
        addressLabel.text = [[categoriesDict objectForKey:checkValue]valueForKey:@"locationAddress"];

        UIImageView *thumbnailImageView = (PFImageView *)[cell viewWithTag:102];
        self.thumbnail= [[categoriesDict objectForKey:checkValue]valueForKey:@"locationImage"];

//        NSLog(@"thumbnail is %@", self.thumbnail);

        if (self.thumbnail == NULL)
        {
                thumbnailImageView.image= [UIImage imageNamed:@"placeholder.jpg"];
        } else
        {
            //Got error occurred
            [self.thumbnail getDataInBackgroundWithBlock:^(NSData *imageData, NSError *error) {
                if (!error) {
                    UIImage *image = [UIImage imageWithData:imageData];
                    thumbnailImageView.image = image;
                }
                else{

                    NSLog(@"imageData value; %@", imageData);
                }
            }];
        }
    return cell;

}

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return [categoriesDict count];

}

-(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
    checkValue = [[categoriesDict allKeys]objectAtIndex:section];
    return [[categoriesDict allKeys]objectAtIndex:section];
}

@end

错误消息

2015-01-14 15:27:36.658 MyLocationDemo[5591:60b] Warning: A long-running operation is being executed on the main thread. 
 Break on warnBlockingOperationOnMainThread() to debug.
2015-01-14 15:28:04.207 MyLocationDemo[5591:60b] -[__NSSetI getDataInBackgroundWithBlock:]: unrecognized selector sent to instance 0xaabed00
2015-01-14 15:28:04.208 MyLocationDemo[5591:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSSetI getDataInBackgroundWithBlock:]: unrecognized selector sent to instance 0xaabed00'
*** First throw call stack:
(
    0   CoreFoundation                      0x027711e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x024f08e5 objc_exception_throw + 44
    2   CoreFoundation                      0x0280e243 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
    3   CoreFoundation                      0x0276150b ___forwarding___ + 1019
    4   CoreFoundation                      0x027610ee _CF_forwarding_prep_0 + 14
    5   MyLocationDemo                      0x000030df -[LocationListTableViewController tableView:cellForRowAtIndexPath:] + 1199
    6   UIKit                               0x012a911f -[UITableView _createPreparedCellForGlobalRow:withIndexPath:] + 412
    7   UIKit                               0x012a91f3 -[UITableView _createPreparedCellForGlobalRow:] + 69
    8   UIKit                               0x0128aece -[UITableView _updateVisibleCellsNow:] + 2428
    9   UIKit                               0x0129f6a5 -[UITableView layoutSubviews] + 213
    10  UIKit                               0x0121f964 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 355
    11  libobjc.A.dylib                     0x0250282b -[NSObject performSelector:withObject:] + 70
    12  QuartzCore                          0x004ee45a -[CALayer layoutSublayers] + 148
    13  QuartzCore                          0x004e2244 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
    14  QuartzCore                          0x004e20b0 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 26
    15  QuartzCore                          0x004487fa _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 294
    16  QuartzCore                          0x00449b85 _ZN2CA11Transaction6commitEv + 393
    17  QuartzCore                          0x005075b0 +[CATransaction flush] + 52
    18  UIKit                               0x011ae9bb _UIApplicationHandleEventQueue + 13095
    19  CoreFoundation                      0x026fa77f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
    20  CoreFoundation                      0x026fa10b __CFRunLoopDoSources0 + 235
    21  CoreFoundation                      0x027171ae __CFRunLoopRun + 910
    22  CoreFoundation                      0x027169d3 CFRunLoopRunSpecific + 467
    23  CoreFoundation                      0x027167eb CFRunLoopRunInMode + 123
    24  GraphicsServices                    0x043555ee GSEventRunModal + 192
    25  GraphicsServices                    0x0435542b GSEventRun + 104
    26  UIKit                               0x011b0f9b UIApplicationMain + 1225
    27  MyLocationDemo                      0x0000391d main + 141
    28  libdyld.dylib                       0x02cba701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)