我如何设置CG_CONTEXT_SHOW_BACKTRACE环境变量？
在我看来，我有三个按钮。在viewDidLoad（）中设置了cornerRadus后：button.layer.cornerRadius = 20我在日志中看到以下错误消息：
<Error>: CGContextSaveGState: invalid context 0x0.
If you want to see the backtrace, please set
CG_CONTEXT_SHOW_BACKTRACE environmental variable.
问题：
我如何设置CG_CONTEXT_SHOW_BACKTRACE环境变量？- 或者我该如何解决这个警告？
Aug 7 14:27:00 <Error>: CGContextSaveGState: invalid context 0x0. Backtrace:
<-[UIStatusBarItemView updateContentsAndWidth]+33>
<-[UIStatusBarItemView initWithItem:data:actions:style:]+477>
<+[UIStatusBarItemView createViewForItem:withData:actions:foregroundStyle:]+134>
<-[UIStatusBarLayoutManager _createViewForItem:withData:actions:]+163>
<-[UIStatusBarLayoutManager _prepareEnabledItemType:withEnabledItems:withData:actions:itemAppearing:itemDisappearing:]+36
<-[UIStatusBarLayoutManager prepareEnabledItems:withData:actions:]+92>
<-[UIStatusBarForegroundView _setStatusBarData:actions:animated:]+797>
<-[UIStatusBarForegroundView setStatusBarData:actions:animated:]+332>
<__51-[UIStatusBar _prepareToSetStyle:animation:forced:]_block_invoke+360>
<+[UIView(Animation) performWithoutAnimation:]+65>
<-[UIStatusBar _prepareToSetStyle:animation:forced:]+866>
<-[UIStatusBar _requestStyleAttributes:animationParameters:forced:]+391>
<-[UIStatusBar requestStyle:animationParameters:forced:]+437>
<-[UIStatusBar requestStyle:animated:forced:]+90>
<-[UIStatusBar _evaluateServerRegistration]+250>
<__45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke+590>
<-[UIView(Hierarchy) _postMovedFromSuperview:]+544>
<-[UIView(Internal) _addSubview:positioned:relativeTo:]+1967>
<-[UIStatusBarWindow setStatusBar:]+288>
<-[UIApplication _createStatusBarWithRequestedStyle:orientation:hidden:]+340>
<-[UIApplication _runWithMainScene:transitionContext:completion:]+950>
<-[UIApplication workspaceDidEndTransaction:]+188>
<-[FBSSerialQueue _performNext]+192>
<-[FBSSerialQueue _performNextFromRunLoopSource]+45>
<__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__+17>
<__CFRunLoopDoSources0+556>
<__CFRunLoopRun+867>
<CFRunLoopRunSpecific+488>
<-[UIApplication _run]+402>
<UIApplicationMain+171>
<main+117>
Aug 7 14:27:00 <Error>: CGContextTranslateCTM: invalid context 0x0. Backtrace:
<-[UIStatusBarItemView updateContentsAndWidth]+33>
<-[UIStatusBarItemView initWithItem:data:actions:style:]+477>
<+[UIStatusBarItemView createViewForItem:withData:actions:foregroundStyle:]+134>
<-[UIStatusBarLayoutManager _createViewForItem:withData:actions:]+163>
<-[UIStatusBarLayoutManager _prepareEnabledItemType:withEnabledItems:withData:actions:itemAppearing:itemDisappearing:]+36
<-[UIStatusBarLayoutManager prepareEnabledItems:withData:actions:]+92>
<-[UIStatusBarForegroundView _setStatusBarData:actions:animated:]+797>
<-[UIStatusBarForegroundView setStatusBarData:actions:animated:]+332>
<__51-[UIStatusBar _prepareToSetStyle:animation:forced:]_block_invoke+360>
<+[UIView(Animation) performWithoutAnimation:]+65>
<-[UIStatusBar _prepareToSetStyle:animation:forced:]+866>
<-[UIStatusBar _requestStyleAttributes:animationParameters:forced:]+391>
<-[UIStatusBar requestStyle:animationParameters:forced:]+437>
<-[UIStatusBar requestStyle:animated:forced:]+90>
<-[UIStatusBar _evaluateServerRegistration]+250>
<__45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke+590>
<-[UIView(Hierarchy) _postMovedFromSuperview:]+544>
<-[UIView(Internal) _addSubview:positioned:relativeTo:]+1967>
<-[UIStatusBarWindow setStatusBar:]+288>
<-[UIApplication _createStatusBarWithRequestedStyle:orientation:hidden:]+340>
<-[UIApplication _runWithMainScene:transitionContext:completion:]+950>
<-[UIApplication workspaceDidEndTransaction:]+188>
<-[FBSSerialQueue _performNext]+192>
<-[FBSSerialQueue _performNextFromRunLoopSource]+45>
<__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__+17>
<__CFRunLoopDoSources0+556>
<__CFRunLoopRun+867>
<CFRunLoopRunSpecific+488>
<-[UIApplication _run]+402>
<UIApplicationMain+171>
<main+117>
Aug 7 14:27:00 <Error>: CGContextRestoreGState: invalid context 0x0. Backtrace:
<-[UIStatusBarItemView updateContentsAndWidth]+33>
<-[UIStatusBarItemView initWithItem:data:actions:style:]+477>
<+[UIStatusBarItemView createViewForItem:withData:actions:foregroundStyle:]+134>
<-[UIStatusBarLayoutManager _createViewForItem:withData:actions:]+163>
<-[UIStatusBarLayoutManager _prepareEnabledItemType:withEnabledItems:withData:actions:itemAppearing:itemDisappearing:]+36
<-[UIStatusBarLayoutManager prepareEnabledItems:withData:actions:]+92>
<-[UIStatusBarForegroundView _setStatusBarData:actions:animated:]+797>
<-[UIStatusBarForegroundView setStatusBarData:actions:animated:]+332>
<__51-[UIStatusBar _prepareToSetStyle:animation:forced:]_block_invoke+360>
<+[UIView(Animation) performWithoutAnimation:]+65>
<-[UIStatusBar _prepareToSetStyle:animation:forced:]+866>
<-[UIStatusBar _requestStyleAttributes:animationParameters:forced:]+391>
<-[UIStatusBar requestStyle:animationParameters:forced:]+437>
<-[UIStatusBar requestStyle:animated:forced:]+90>
<-[UIStatusBar _evaluateServerRegistration]+250>
<__45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke+590>
<-[UIView(Hierarchy) _postMovedFromSuperview:]+544>
<-[UIView(Internal) _addSubview:positioned:relativeTo:]+1967>
<-[UIStatusBarWindow setStatusBar:]+288>
<-[UIApplication _createStatusBarWithRequestedStyle:orientation:hidden:]+340>
<-[UIApplication _runWithMainScene:transitionContext:completion:]+950>
<-[UIApplication workspaceDidEndTransaction:]+188>
<-[FBSSerialQueue _performNext]+192>
<-[FBSSerialQueue _performNextFromRunLoopSource]+45>
<__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__+17>
<__CFRunLoopDoSources0+556>
<__CFRunLoopRun+867>
<CFRunLoopRunSpecific+488>
<-[UIApplication _run]+402>
<UIApplicationMain+171>
<main+117>
回答 2
Stack Overflow用户
发布于 2018-05-04 09:13:10
这是9b5中的一个错误：https://forums.developer.apple.com/thread/13683
Stack Overflow用户
发布于 2018-05-04 10:34:06
可以通过以下菜单设置环境变量：产品 - >方案 - >编辑方案。在“运行”项目下，找到“参数”选项卡，您会看到选项卡中的“环境变量”，添加CG_CONTEXT_SHOW_BACKTRACE并将其值设置为YES。
https://stackoverflow.com/questions/-100008355
复制相似问题