App Crash: An instance 0xXXXXXXXX of class Charts.BarChartView was deallocated while key value observers were still registered with it.

[jakarmy]

I'm adding a BarChartView to a CollectionView-like class that deallocates and reuses cells. I add to one of these cells a BarChartView, and when you scroll up and down, the app crashes with this error:

App Crash:
An instance 0x7cba6e00 of class Charts.BarChartView was deallocated while key value observers were still registered with it. Current observation info: <NSKeyValueObservationInfo 0x7e4626a0> (
<NSKeyValueObservance 0x7c0d6090: Observer: 0x7cba6e00, Key path: bounds, Options: <New: YES, Old: NO, Prior: NO> Context: 0x0, Property: 0x7c0d60c0>
<NSKeyValueObservance 0x7c0cb910: Observer: 0x7cba6e00, Key path: frame, Options: <New: YES, Old: NO, Prior: NO> Context: 0x0, Property: 0x7c0cb940>
)
2016-08-28 20:06:01.937 VirtualStatBasic[14383:2869686] Stack Trace:
(
0 CoreFoundation 0x055a8494 exceptionPreprocess + 180
1 libobjc.A.dylib 0x05062e02 objc_exception_throw + 50
2 CoreFoundation 0x055a83bd +[NSException raise:format:] + 141
3 Foundation 0x04c9b097 NSKVODeallocate + 353
4 UIKit 0x03fd6348 -[UIView(UIKitManual) release] + 142
5 CoreFoundation 0x05457df7 CFRelease + 727
6 CoreFoundation 0x0546dbfe -[__NSArrayM dealloc] + 142
7 libobjc.A.dylib 0x05076060 _ZN11objc_object17sidetable_releaseEb + 238
8 libobjc.A.dylib 0x05075361 objc_release + 65
9 libobjc.A.dylib 0x0507652d _ZN12_GLOBAL__N_119AutoreleasePoolPage3popEPv + 371
10 CoreFoundation 0x054788a8 _CFAutoreleasePoolPop + 24
11 Foundation 0x04c6e23f __NSFireDelayedPerform + 520
12 CoreFoundation 0x054f2136 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION + 22
13 CoreFoundation 0x054f1b32 __CFRunLoopDoTimer + 1250
14 CoreFoundation 0x054b039a __CFRunLoopRun + 2202
15 CoreFoundation 0x054af846 CFRunLoopRunSpecific + 470
16 CoreFoundation 0x054af65b CFRunLoopRunInMode + 123
17 GraphicsServices 0x0ad41664 GSEventRunModal + 192
18 GraphicsServices 0x0ad414a1 GSEventRun + 104
19 UIKit 0x036e6eb9 UIApplicationMain + 160
20 VirtualStatBasic 0x00008e0a main + 138
21 libdyld.dylib 0x05a54a25 start + 1
)

I believe the deallocation of cell-like objects containing the BarChartView might be causing the problem.

What would you suggest? Is there a way to remove the Key Value Observers?

[danielgindi]

The chart view removes any observes (to be exact: 2) that it registers (in init) - in dealloc, so I'm guessing there's a problem in your code in another place....