我们目前正在对一个新应用程序进行 beta 测试，在该应用程序中我遇到了一些我不理解的崩溃。它不会发生在我的设备或模拟器上，但会在我们部署用于测试的现场的一些设备上崩溃。与此相关的代码是：
@implementation NSMutableAttributedString (Helper)
-(NSRange)appendString:(NSString *)string withAttributes:(NSDictionary *)attributes {
if (![self respondsToSelector:@selector(length)]) {
DDLogError(@"SELF can't respond to length selector. Wonder what is going on here... \n%@", [NSThread callStackSymbols]);
DDLogError(@"SELF is of type %@", [self class]);
}
NSUInteger loc = self.length;
if (string == nil) return NSMakeRange(loc, 0);
if (![string isKindOfClass:[NSString class]]) {
DDLogError(@"Got a non string in my appendString function. Wonder what is going on here... \n%@", [NSThread callStackSymbols]);
DDLogError(@"string is of type %@", [string class]);
return NSMakeRange(loc, 0);
}
[self.mutableString appendString:string];
NSRange ret = NSMakeRange(loc, string.length);
if (attributes != nil) [self addAttributes:attributes range:ret];
return ret;
}
-(NSRange)appendString:(NSString *)string {
return [self appendString:string withAttributes:nil]; // THIS IS LINE 40!
}
@end
崩溃日志如下所示：
Incident Identifier: F9945D73-60D1-438D-B2CE-76634A501D69
CrashReporter Key: 91DBE709-85A2-4F9E-AF82-6D7C0248F443
Hardware Model: iPhone3,1
Process: HDScores [152]
Path: /Users/USER/HDScores.app/HDScores
Identifier: com.hdscores.consumer.service.clients.ios
Version: 1.23
Code Type: ARM
Parent Process: launchd [1]
Date/Time: 2014-07-16T19:56:43Z
OS Version: iPhone OS 7.1.2 (11D257)
Report Version: 104
Exception Type: SIGSEGV
Exception Codes: SEGV_ACCERR at 0x6570706d
Crashed Thread: 0
Application Specific Information:
objc_msgSend() selector name: length
Thread 0 Crashed:
0 libobjc.A.dylib 0x3a33d626 objc_msgSend + 6
1 TextToSpeech 0x374a0431 TTSCopyModificationDateForFileAtURL + 1610
2 HDScores 0x00030935 -[NSMutableAttributedString(Helper) appendString:] (NSMutableAttributedString+Helper.m:40)
3 HDScores 0x00037fe7 -[EstablishmentDetailViewController viewDidLoad] (EstablishmentDetailViewController.m:170)
4 UIKit 0x323a44ab -[UIViewController loadViewIfRequired] + 516
5 UIKit 0x3244ebe1 -[UINavigationController _layoutViewController:] + 30
6 UIKit 0x3244eaf7 -[UINavigationController _updateScrollViewFromViewController:toViewController:] + 228
7 UIKit 0x3244e0d3 -[UINavigationController _startTransition:fromViewController:toViewController:] + 76
8 UIKit 0x3244ddfd -[UINavigationController _startDeferredTransitionIfNeeded:] + 570
9 UIKit 0x3244db6d -[UINavigationController __viewWillLayoutSubviews] + 42
10 UIKit 0x3244db05 -[UILayoutContainerView layoutSubviews] + 182
11 UIKit 0x025d1ab3 0x2580000 + 334515
12 UIKit 0x3239fd59 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 378
13 QuartzCore 0x3201d62b -[CALayer layoutSublayers] + 140
14 QuartzCore 0x32018e3b CA::Layer::layout_if_needed(CA::Transaction*) + 348
15 QuartzCore 0x32018ccd CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 14
16 QuartzCore 0x320186df CA::Context::commit_transaction(CA::Transaction*) + 228
17 QuartzCore 0x320184ef CA::Transaction::commit() + 312
18 QuartzCore 0x3201221d CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 54
19 CoreFoundation 0x2fb4e255 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 18
20 CoreFoundation 0x2fb4bbf9 __CFRunLoopDoObservers + 282
21 CoreFoundation 0x2fb4bf3b __CFRunLoopRun + 728
22 CoreFoundation 0x2fab6ebf CFRunLoopRunSpecific + 520
23 CoreFoundation 0x2fab6ca3 CFRunLoopRunInMode + 104
24 GraphicsServices 0x349bc663 GSEventRunModal + 136
25 UIKit 0x3240314d UIApplicationMain + 1134
26 HDScores 0x0003daab main (main.m:17)
27 libdyld.dylib 0x3a840ab7 start + 0
有人有想法么？我可以告诉你 DDLogError 语句永远不会被击中，作为尝试诊断问题的最后一道防线。看起来它正在发送错误，因为长度不是已知的选择器。同样，这仅出现在 iPhone 上，而不是具有相同代码的 iPad。到目前为止，只有几部 iPhone（一部是 5，一部是 4），都在 IOS 7 上。任何帮助，我都在为这个而烦恼……