ios - 我的代码如何产生此崩溃 : [NSConcreteData count]: unrecognized selector sent to instance

Question

我在 BugSense 中看到了这个崩溃:

-[NSConcreteData count]: unrecognized selector sent to instance 0x14e57f10 - NSInvalidArgumentException

在这段代码中:

+ (NSMutableArray *)applyFilters:(NSMutableArray *)theItems fromFilter:(NSDictionary *)filters
{    
    NSMutableArray *items = [[NSMutableArray alloc] initWithArray:theItems];

    if ([[filters allKeys] count] > 0)
    {
        NSMutableArray *tempFilteredItems = [[NSMutableArray alloc] init];

        for (NSString *key in [filters allKeys])
        {
            NSMutableString *convertedKey = [NSMutableString stringWithString:key];

            [convertedKey replaceOccurrencesOfString:@" " 
                                       withString:@"_" 
                                          options:NSCaseInsensitiveSearch 
                                            range:NSMakeRange(0, [convertedKey length])];

            NSArray *tempFilterAttributes = [NSArray arrayWithArray:filters[key]];

            for (NSDictionary *item in items) 
            {   
                if (![[item[convertedKey] componentsSeparatedByString:@"*"] firstObjectCommonWithArray:tempFilterAttributes])
                {
                    if (![tempFilteredItems containsObject:item])
                    {
                        [tempFilteredItems addObject:item];
                    }
                }
            }

            [items removeObjectsInArray:tempFilteredItems];
            [tempFilteredItems removeAllObjects];
        }        
    }

    return items;
}

为什么/这是怎么发生的？

堆栈跟踪是:

    CoreFoundation  <redacted> + 130    
1   libobjc.A.dylib objc_exception_throw + 38   
2   CoreFoundation  <redacted> + 202    
3   CoreFoundation  <redacted> + 706    
4   CoreFoundation  _CF_forwarding_prep_0 + 24  
5   CoreFoundation  <redacted> + 28 
6   Video Games +[Helper applyFilters:fromFilter:] (Helper.m:2862)  
7   Video Games -[WishlistViewController loadUp] (WishlistViewController.m:409) + 29303 
8   Video Games -[WishlistViewController viewWillAppear:] (WishlistViewController.m:363) + 27955    
9   UIKit   <redacted> + 374    
10  UIKit   <redacted> + 612    
11  UIKit   <redacted> + 572    
12  UIKit   <redacted> + 44 
13  UIKit   <redacted> + 184    
14  UIKit   <redacted> + 380    
15  QuartzCore  <redacted> + 142    
16  QuartzCore  <redacted> + 350    
17  QuartzCore  <redacted> + 16 
18  QuartzCore  <redacted> + 228    
19  QuartzCore  <redacted> + 314    
20  UIKit   <redacted> + 126    
21  CoreFoundation  <redacted> + 20 
22  CoreFoundation  <redacted> + 286    
23  CoreFoundation  <redacted> + 738    
24  CoreFoundation  CFRunLoopRunSpecific + 524  
25  CoreFoundation  CFRunLoopRunInMode + 106    
26  GraphicsServices    GSEventRunModal + 138   
27  UIKit   UIApplicationMain + 1136    
28  Video Games main (main.m:16) + 888911   
29  libdyld.dylib   <redacted> + 2

Answer 1

问题与您提供的代码无关。错误消息表明消息 count 被发送到 class NSConcreteData，这与 NSData 基本相同, 这样的类方法是不存在的。
我建议您设置一个异常断点(在 Xcode 中选择左侧的断点导航器，单击左下角的+，然后选择添加异常断点)。
当您执行该应用程序时，它将在错误指令处停止。

编辑(由于您现在提供的堆栈跟踪):
堆栈跟踪确实表明您的方法 applyFilters:fromFilter: 是导致崩溃的原因。在此方法中发送消息 count 的唯一位置是语句 [[filters allKeys] count]。看起来 count 被发送到一个 NSConcreteData 对象，而不是像您预期的那样发送到一个 NSArray 对象。一个原因可能是参数 filters，它应该是一个 NSDictionary，是一个不同类型的对象。
所以当应用程序停止在异常断点时，请检查实例的类 filters。