使用以下崩溃在iOS应用上工作：
由于未捕获的异常'NSRangeException'而终止应用，原因：＆gt;' initWithCoder :: MKMapView＆gt;必须在主线程上初始化。
更奇怪的是，调用堆栈表明这源于我的代码（保存地图的控制器）中的嵌入segue。然而，地图已经可见并且是交互式的，所以看起来这很奇怪。
15 UIKit 0x00000001071ffc07 __67- [UIStoryboardEmbedSegueTemplate newDefaultPerformHandlerForSegue：] _ block_invoke + 180
我已启用主线程检查器和暂停我的调试方案中的问题（已验证它已设置为调试，并通过故意放入一些后台线程UI更新代码并将其删除来验证它的运行主线程检查器启动后）。
我会假设主线程检查器会抓住任何它我做错了：地图，我会得到一个方便 “UI API在后台线程上调用”。但是，我得到的只是崩溃，所以不知道我会做错了什么：线程（我相信所有的UI更新都包含在通常的dispatchqueue.main.async等中），以便我可以解决它。
a）我是否误解主线程检查器的工作原理？
b）之前有没有人遇到Mapkit +嵌入segues这个问题？
c）有没有另一种方法来捕捉它可能做错了什么？如果它有帮助，则完整的堆栈跟踪。请注意，在选项卡和地图已经加载并且存在于UI中之后，我收到此。
2017-12-20 23:04:34.829770-0800 XXXXXX[93019:3557775] This application is modifying the autolayout engine from a background thread after the engine was accessed from the main thread. This can lead to engine corruption and weird crashes.
Stack:(
0 Foundation 0x0000000103a76ec6 _AssertAutolayoutOnAllowedThreadsOnly + 77
1 Foundation 0x0000000103880d7a -[NSISEngine withBehaviors:performModifications:] + 28
2 UIKit 0x0000000106ecb5e8 -[UIView(UIConstraintBasedLayout) _resetLayoutEngineHostConstraints] + 75
3 UIKit 0x00000001064356c2 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1388
4 QuartzCore 0x00000001061a13ee -[CALayer layoutSublayers] + 153
5 QuartzCore 0x00000001061a54dd _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 401
6 QuartzCore 0x000000010612dded _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 365
7 QuartzCore 0x0000000106159704 _ZN2CA11Transaction6commitEv + 500
8 QuartzCore 0x0000000106159d79 _ZN2CA11Transaction14release_threadEPv + 213
9 libsystem_pthread.dylib 0x000000010b3d539f _pthread_tsd_cleanup + 544
10 libsystem_pthread.dylib 0x000000010b3d50d9 _pthread_exit + 152
11 libsystem_pthread.dylib 0x000000010b3d365d pthread_attr_getschedpolicy + 0
12 libsystem_pthread.dylib 0x000000010b3d307d start_wqthread + 13
)
2017-12-20 23:04:34.850538-0800 XXXXXX[93019:3557775] *** Terminating app due to uncaught exception 'NSRangeException', reason: '<MKMapView: 0x7f8d30a9b200; frame = (0 0; 0 0); transform = [0, 0, 0, 0, 0, 0]; alpha = 0; opaque = NO; layer = (null)> initWithCoder:: MKMapView must be initialized on the main thread.'
*** First throw call stack:
(
0 CoreFoundation 0x0000000104bf71ab __exceptionPreprocess + 171
1 libobjc.A.dylib 0x0000000103e51f41 objc_exception_throw + 48
2 CoreFoundation 0x0000000104c6bcb5 +[NSException raise:format:] + 197
3 MapKit 0x0000000102e09546 -[MKMapView initWithCoder:] + 1368
4 UIKit 0x0000000106a42a45 UINibDecoderDecodeObjectForValue + 704
5 UIKit 0x0000000106a4277a -[UINibDecoder decodeObjectForKey:] + 89
6 UIKit 0x00000001067f0218 -[UIRuntimeConnection initWithCoder:] + 178
7 UIKit 0x0000000106a42a45 UINibDecoderDecodeObjectForValue + 704
8 UIKit 0x0000000106a42be3 UINibDecoderDecodeObjectForValue + 1118
9 UIKit 0x0000000106a4277a -[UINibDecoder decodeObjectForKey:] + 89
10 UIKit 0x00000001067ef415 -[UINib instantiateWithOwner:options:] + 1262
11 UIKit 0x0000000106508838 -[UIViewController _loadViewFromNibNamed:bundle:] + 383
12 UIKit 0x0000000106509164 -[UIViewController loadView] + 177
13 UIKit 0x0000000106509495 -[UIViewController loadViewIfRequired] + 195
14 UIKit 0x0000000106509cf2 -[UIViewController view] + 27
15 UIKit 0x0000000106fa0c07 __67-[UIStoryboardEmbedSegueTemplate newDefaultPerformHandlerForSegue:]_block_invoke + 180
16 UIKit 0x0000000106c8bdcb -[UIStoryboardSegueTemplate _performWithDestinationViewController:sender:] + 279
17 UIKit 0x0000000106c8bc83 -[UIStoryboardSegueTemplate _perform:] + 82
18 UIKit 0x0000000106c8bf4b -[UIStoryboardSegueTemplate perform:] + 157
19 UIKit 0x0000000106509685 -[UIViewController loadViewIfRequired] + 691
20 UIKit 0x0000000106509cf2 -[UIViewController view] + 27
21 UIKit 0x0000000106578094 -[UITabBarController transitionFromViewController:toViewController:transition:shouldSetSelected:] + 466
22 UIKit 0x0000000106577417 -[UITabBarController transitionFromViewController:toViewController:] + 59
23 UIKit 0x0000000106573404 -[UITabBarController _setSelectedViewController:] + 410
24 UIKit 0x00000001065731d3 -[UITabBarController setSelectedViewController:] + 109
25 UIKit 0x00000001064268f0 +[UIView(Animation) performWithoutAnimation:] + 90
26 UIKit 0x000000010656d6dc -[UITabBarController _selectDefaultViewControllerIfNecessaryWithAppearanceTransitions:] + 512
27 UIKit 0x000000010656e727 -[UITabBarController viewWillAppear:] + 211
28 UIKit 0x000000010650f59c -[UIViewController _setViewAppearState:isAnimating:] + 444
29 UIKit 0x000000010650fe31 -[UIViewController __viewWillAppear:] + 147
30 UIKit 0x00000001065517da -[UINavigationController _startTransition:fromViewController:toViewController:] + 843
31 UIKit 0x000000010655263f -[UINavigationController _startDeferredTransitionIfNeeded:] + 841
32 UIKit 0x00000001065538c3 -[UINavigationController __viewWillLayoutSubviews] + 150
33 UIKit 0x00000001067aca49 -[UILayoutContainerView layoutSubviews] + 231
34 UIKit 0x00000001064356f5 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1439
35 QuartzCore 0x00000001061a13ee -[CALayer layoutSublayers] + 153
36 QuartzCore 0x00000001061a54dd _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 401
37 QuartzCore 0x000000010612dded _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 365
38 QuartzCore 0x0000000106159704 _ZN2CA11Transaction6commitEv + 500
39 QuartzCore 0x0000000106159d79 _ZN2CA11Transaction14release_threadEPv + 213
40 libsystem_pthread.dylib 0x000000010b3d539f _pthread_tsd_cleanup + 544
41 libsystem_pthread.dylib 0x000000010b3d50d9 _pthread_exit + 152
42 libsystem_pthread.dylib 0x000000010b3d365d pthread_attr_getschedpolicy + 0
43 libsystem_pthread.dylib 0x000000010b3d307d start_wqthread + 13
)
libc++abi.dylib: terminating with uncaught exception of type NSException
答案 0 :(得分：0)
根据the docs：
主线程检查器是Swift和C语言的独立工具，可检测后台线程上AppKit，UIKit和其他API的无效使用。
他们对“其他API”的定义可能不包括MapKit。我知道MKMapView在技术上继承了NSView或UIView，具体取决于平台，但我会说主线程检查器可能没有捕获UIKit，AppKit和你的app之外的任何警告或信号（我不知道）这肯定，只是一个猜测。）
一个常见问题是尝试在viewDidLoad()中执行segue，但看起来你似乎并没有这样做。
您是否正在做任何导致无意中在后台线程上触发segue的事情？