Question

我不明白问题，但我想故事板中的问题（在我的约束中，因为有时候对象不是他们必须的地方）。

*由于未捕获的异常'NSGenericException'而终止应用，原因：'*

Collection <__NSSetM: 0x7fae0b5e6900> was mutated while being enumerated.'
*** First throw call stack:

 - (
    0   CoreFoundation   __exceptionPreprocess + 165

    1   libobjc.A.dylib  objc_exception_throw + 45

    2   CoreFoundation __NSFastEnumerationMutationHandler + 132

    3   Foundation  -[NSISEngine substituteOutAllOccurencesOfBodyVar:withExpression:] + 336

    4   Foundation -[NSISEngine pivotToMakeBodyVar:newHeadOfRowWithHead:andDropRow:] + 330

    5   Foundation   -[NSISEngine minimizeConstantInObjectiveRowWithHead:] + 314

    6   Foundation  -[NSISEngine tryUsingArtificialVariableToAddConstraintWithMarker:rowBody:usingInfeasibilityHandlingBehavior:mutuallyExclusiveConstraints:] + 285

    7   Foundation  -[NSISEngine tryToAddConstraintWithMarker:expression:integralizationAdjustment:mutuallyExclusiveConstraints:] + 691

    8   Foundation   -[NSLayoutConstraint _addLoweredExpression:toEngine:integralizationAdjustment:lastLoweredConstantWasRounded:mutuallyExclusiveConstraints:] + 275

    9   Foundation   -[NSLayoutConstraint _addToEngine:integralizationAdjustment:mutuallyExclusiveConstraints:] + 220

    10  UIKit  -[UIView(UIConstraintBasedLayout) _layoutEngine_didAddLayoutConstraint:roundingAdjustment:mutuallyExclusiveConstraints:] + 411

    11  UIKit -[UIView(UIConstraintBasedLayout) _tryToAddConstraintWithoutUpdatingConstraintsArray:roundingAdjustment:mutuallyExclusiveConstraints:] + 30

    12  UIKit [UIView(UIConstraintBasedLayout) _tryToAddConstraint:roundingAdjustment:mutuallyExclusiveConstraints:] + 243

    13  UIKit -[UIView(UIConstraintBasedLayout) addConstraints:]_block_invoke + 188

    14  Foundation [NSISEngine withBehaviors:performModifications:] + 155

    15  UIKit  [UIView(UIConstraintBasedLayout) addConstraints:] + 263

    16  UIKit-[UIView _setTraitStorageConstraints:] + 794

Answer 1

这不是自动布局的问题。您正在使用数组或字典或某些NSSet对象变异（正在添加值），而枚举（正在从中读取值）。< / p>

当您填充类似数组的内容然后重新加载UITableView或UICollectionView

时，会出现此问题

Answer 2

也许其他一些后台线程和主线程同时调用autolayout函数。查看崩溃日志中的其他线程。

因未捕获的异常'NSGenericException'而终止应用程序，原因：'*** Collection＆lt; __ NSSetM ...＆gt;在被列举时发生了变异。

2 个答案: