没有网络时，调用触发闪退，日志如下，调试时也发现，( value = [self valueForKey:propertyName];) propertyName为nil 导致的crash

[aKeyDistance]

Date/Time: 2017-11-15 10:50:04.8824 +0800
Launch Time: 2017-11-15 10:37:07.8401 +0800
OS Version: iPhone OS 11.0 (15A372)
Baseband Version: 6.17.00
Report Version: 104

Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Triggered by Thread: 0

Application Specific Information:
abort() called

Filtered syslog:
None found

Last Exception Backtrace:
0 CoreFoundation 0x186553d38 __exceptionPreprocess + 124
1 libobjc.A.dylib 0x185a68528 objc_exception_throw + 55
2 CoreFoundation 0x1865611f8 -[NSObject+ 1372664 (NSObject) doesNotRecognizeSelector:] + 139
3 UIKit 0x18fd1acc4 -[UIResponder doesNotRecognizeSelector:] + 295
4 CoreFoundation 0x1865596e4 forwarding + 1379
5 CoreFoundation 0x18643f0dc _CF_forwarding_prep_0 + 91
6 xxxxxxx 0x10117365c -[NSObject(HYBUnicodeReadable) description] + 2340444 (NSObject+HYBUnicodeReadable.m:38)
7 Foundation 0x186e38a60 _NSDescriptionWithLocaleFunc + 107
8 CoreFoundation 0x1865126fc __CFStringAppendFormatCore + 11587
9 CoreFoundation 0x186513658 _CFStringCreateWithFormatAndArgumentsAux2 + 131
10 CoreFoundation 0x1865406c8 _CFLogvEx2Predicate + 155
11 CoreFoundation 0x186540a70 _CFLogvEx3 + 475
12 Foundation 0x186f23524 _NSLogv + 127
13 Foundation 0x186e48094 NSLog + 31

[LionNeo]

你好这个问题 我也是遇到了,我的解决方案是这样,希望可以帮助到你: