我正在使用带有一些标签的UITableView＆amp;图像在其单元格中。从服务器获取数据后填充数据。 大多数情况下它运行正常，但有时app会因此跟踪而崩溃：
Terminating app due to uncaught exception 'NSGenericException', reason: '*** Collection <__NSSetM: 0x79938670> was mutated while being enumerated.'
*** First throw call stack:
(
0 CoreFoundation 0x05bde746 __exceptionPreprocess + 182
1 libobjc.A.dylib 0x05867a97 objc_exception_throw + 44
2 CoreFoundation 0x05bddfe6 __NSFastEnumerationMutationHandler + 166
3 Foundation 0x01b80617 -[NSISEngine chooseOutgoingRowHeadForIncomingRowHead:] + 347
4 Foundation 0x01b7dc60 -[NSISEngine minimizeConstantInObjectiveRowWithHead:] + 228
5 Foundation 0x01d32349 -[NSISEngine tryUsingArtificialVariableToAddConstraintWithMarker:rowBody:usingInfeasibilityHandlingBehavior:mutuallyExclusiveConstraints:] + 291
6 Foundation 0x01b7b4cb -[NSISEngine tryToAddConstraintWithMarker:expression:integralizationAdjustment:mutuallyExclusiveConstraints:] + 760
7 Foundation 0x01d3a02f -[NSLayoutConstraint _addLoweredExpression:toEngine:integralizationAdjustment:lastLoweredConstantWasRounded:mutuallyExclusiveConstraints:] + 280
8 Foundation 0x01b6e93b -[NSLayoutConstraint _addToEngine:integralizationAdjustment:mutuallyExclusiveConstraints:] + 258
9 UIKit 0x029f81bc -[UIView(UIConstraintBasedLayout) _layoutEngine_didAddLayoutConstraint:roundingAdjustment:mutuallyExclusiveConstraints:] + 450
10 UIKit 0x029f8507 -[UIView(UIConstraintBasedLayout) _tryToAddConstraintWithoutUpdatingConstraintsArray:roundingAdjustment:mutuallyExclusiveConstraints:] + 61
11 UIKit 0x029f865c -[UIView(UIConstraintBasedLayout) _tryToAddConstraint:roundingAdjustment:mutuallyExclusiveConstraints:] + 281
12 UIKit 0x029f8854 -[UIView(UIConstraintBasedLayout) nsli_addConstraint:] + 56
13 UIKit 0x029f8814 -[UIView(UIConstraintBasedLayout) _addConstraint:] + 218
14 UIKit 0x029f8735 -[UIView(UIConstraintBasedLayout) addConstraint:] + 40
15 UIKit 0x029f8a2f __50-[UIView(UIConstraintBasedLayout) addConstraints:]_block_invoke + 172
16 Foundation 0x01b7e077 -[NSISEngine withBehaviors:performModifications:] + 150
17 Foundation 0x01b815cf -[NSISEngine withAutomaticOptimizationDisabled:] + 48
18 UIKit 0x029f7d9f -[UIView(UIConstraintBasedLayout) _withAutomaticEngineOptimizationDisabled:] + 64
19 UIKit 0x029f897b -[UIView(UIConstraintBasedLayout) addConstraints:] + 290
20 UIKit 0x029fa262 -[UIView(UIConstraintBasedLayout) _updateLayoutEngineHostConstraints] + 612
21 UIKit 0x02a060db -[UIView(AdditionalLayoutSupport) updateConstraints] + 58
22 UIKit 0x02a055a4 -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:] + 300
23 UIKit 0x02a05837 __125-[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:]_block_invoke + 43
24 Foundation 0x01b7e077 -[NSISEngine withBehaviors:performModifications:] + 150
25 Foundation 0x01b815cf -[NSISEngine withAutomaticOptimizationDisabled:] + 48
26 UIKit 0x02a04fab -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 64
27 UIKit 0x02a05804 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:] + 127
28 UIKit 0x02a0577f __UIViewRecursionHelper + 41
29 CoreFoundation 0x05ad1529 CFArrayApplyFunction + 57
30 UIKit 0x02a05527 -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:] + 175
31 UIKit 0x02a05804 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPassAndViewsNeedingBaselineUpdate:] + 127
32 UIKit 0x02a05d96 __60-[UIView(AdditionalLayoutSupport) updateConstraintsIfNeeded]_block_invoke + 105
33 UIKit 0x02a04fb3 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 72
34 UIKit 0x02a059ec -[UIView(AdditionalLayoutSupport) updateConstraintsIfNeeded] + 248
35 UIKit 0x027a0065 -[UITableViewCellContentView updateConstraintsIfNeeded] + 106
36 UIKit 0x02a0624d -[UIView(AdditionalLayoutSupport) _updateConstraintsAtEngineLevelIfNeeded] + 191
37 UIKit 0x0231137e -[UIView(Hierarchy) _updateConstraintsAsNecessaryAndApplyLayoutFromEngine] + 120
38 UIKit 0x0231167c -[UIView(Hierarchy) layoutSubviews] + 57
39 UIKit 0x0244e8c9 -[UIImageView layoutSubviews] + 217
40 UIKit 0x0231f52a -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 668
41 libobjc.A.dylib 0x0587d771 -[NSObject performSelector:withObject:] + 70
42 QuartzCore 0x020bde47 -[CALayer layoutSublayers] + 144
43 QuartzCore 0x020b1925 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 403
44 QuartzCore 0x020b177a _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 26
45 QuartzCore 0x0200dc22 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 284
46 QuartzCore 0x0200f0b5 _ZN2CA11Transaction6commitEv + 487
47 QuartzCore 0x0200f7cc _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 92
48 CoreFoundation 0x05aff86e __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
49 CoreFoundation 0x05aff7b0 __CFRunLoopDoObservers + 400
50 CoreFoundation 0x05af51ea __CFRunLoopRun + 1226
51 CoreFoundation 0x05af4a5b CFRunLoopRunSpecific + 443
52 CoreFoundation 0x05af488b CFRunLoopRunInMode + 123
53 GraphicsServices 0x075492c9 GSEventRunModal + 192
54 GraphicsServices 0x07549106 GSEventRun + 104
55 UIKit 0x0228c0b6 UIApplicationMain + 1526
56 NightStay 0x001aa2aa main + 138
57 libdyld.dylib 0x061baac9 start + 1
58 ??? 0x00000001 0x0 + 1
有人可以为此提供帮助吗？