Not sure where to start with Accessibility crash

Question

Created Nov ’16

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I started noticing a crash in my app a few weeks ago, and I've been unable to figure out what's going wrong or even where to start. I can reproduce it every time just by pointing the Accessibility Inspector at the Simulator while my app is running, and it doesn't seem to matter which part of my app UI is visible at the time, it always crashes with "-[UIView floating]: unrecognized selector sent to instance". No hits on Stack Overflow or other forums. My app's UI is mostly a combination of the standard split/tab/table views with a bunch of custom controls, but nothing too crazy. Anyone out there have pointers for where to start? I'm sure it's only one or two users, but after seeing those inspiring AX videos that Apple posted, I'd really love to fix this.

2016-11-01 16:11:27.977 Lightbow[45084:1218801] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIView floating]: unrecognized selector sent to instance 0x7fc0b9694c00'
*** First throw call stack:
(
  0   CoreFoundation                      0x0000000111e9b34b __exceptionPreprocess + 171
  1   libobjc.A.dylib                     0x00000001118fc21e objc_exception_throw + 48
  2   CoreFoundation                      0x0000000111f0af34 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132
  3   CoreFoundation                      0x0000000111e20c15 ___forwarding___ + 1013
  4   CoreFoundation                      0x0000000111e20798 _CF_forwarding_prep_0 + 120
  5   UIKit                               0x0000000126f90afc -[UITableViewAccessibility _accessibilitySortedElementsWithin] + 512
  6   UIKit                               0x0000000126faf007 -[UIScrollViewAccessibility _accessibilityFirstLastOpaqueElement:] + 123
  7   UIKit                               0x0000000126f7ac17 -[UIApplicationAccessibility _findContainerAccessibleElement:first:focus:allowScrolling:] + 465
  8   UIKit                               0x0000000126f7baff -[UIApplicationAccessibility _accessibilityElementFirst:last:forFocus:allowScrolling:] + 1018
  9   UIKit                               0x0000000126f7f802 -[UIApplicationAccessibility accessibilityAttributeValue:] + 428
  10  UIAccessibility                     0x0000000127104646 _copyAttributeValueCallback + 207
  11  AXRuntime                           0x0000000126e699f2 _AXXMIGCopyAttributeValue + 167
  12  AXRuntime                           0x0000000126e63c34 _XCopyAttributeValue + 274
  13  AXRuntime                           0x0000000126e73545 mshMIGPerform + 266
  14  CoreFoundation                      0x0000000111e2cf89 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 41
  15  CoreFoundation                      0x0000000111e2cf01 __CFRunLoopDoSource1 + 465
  16  CoreFoundation                      0x0000000111e25045 __CFRunLoopRun + 2389
  17  CoreFoundation                      0x0000000111e24494 CFRunLoopRunSpecific + 420
  18  GraphicsServices                    0x000000011734ba6f GSEventRunModal + 161
  19  UIKit                               0x000000010eb67f34 UIApplicationMain + 159
  20  Lightbow                            0x000000010c49e82f main + 111
  21  libdyld.dylib                       0x000000011322568d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

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Answer 1

lightbow OP

Nov ’16

I added a category method to UIView called "floating" to see if I could get any information about the caller or the context. Every time, I get a view with no superview, and a single UILabel subview (textless, unfortunately).

(lldb) po self
<UIView: 0x7f7fc7f02160; frame = (0 0; 320 10); layer = <CALayer: 0x618000629020>>

(lldb) po self.subviews
<__NSArrayM 0x618000a44350>(
<UILabel: 0x7f7fc7f02810; frame = (10 0; 310 10); opaque = NO; userInteractionEnabled = NO; layer = <_UILabelLayer: 0x618000482940>>
)

(lldb) po self.superview
0x0000000000000000

I'm getting four calls to this method per UITableViewCell in my table, and it happens regardless of whether I'm in a table with standard or custom UITableView cells. Anyone know what -[UITableViewAccessibility _accessibilitySortedElementsWithin] might be doing with such a view?

0