Intermittent crash on closure

Please help, how can I protect against this type of crash?

Crash log: Crashed: com.apple.main-thread 0 myapp 0x10292ac14 GetStartedQuickVC.viewDidLoad() + 89 (GetStartedQuickVC.swift:89) 1 myapp 0x10292b2a0 @objc GetStartedQuickVC.viewDidLoad() + 4297503392 (:4297503392) 2 UIKitCore 0x18b478658 -[UIViewController _sendViewDidLoadWithAppearanceProxyObjectTaggingEnabled] + 100 3 UIKitCore 0x18b47d0e8 -[UIViewController loadViewIfRequired] + 936 4 UIKitCore 0x18b47d4f0 -[UIViewController view] + 28 5 UIKitCore 0x18b492b6c -[UIViewController _setPresentationController:] + 108 6 UIKitCore 0x18b48b95c -[UIViewController _presentViewController:modalSourceViewController:presentationController:animationController:interactionController:completion:] + 1344 7 UIKitCore 0x18b48d358 -[UIViewController _presentViewController:withAnimationController:completion:] + 4228 8 UIKitCore 0x18b48f864 __63-[UIViewController _presentViewController:animated:completion:]_block_invoke + 104 9 UIKitCore 0x18b48fd6c -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 508 10 UIKitCore 0x18b48f7b4 -[UIViewController presentViewController:animated:completion:] + 196 11 UIKitCore 0x18b48fa20 -[UIViewController presentViewController:animated:completion:] + 164 12 myapp 0x1028eaf00 GetStartedVC.onQuickUpdate(:) + 369 (GetStartedVC.swift:369) 13 myapp 0x1028f9408 @objc GetStartedVC.onClose(_:) + 4297298952 14 UIKitCore 0x18bac172c -[UIApplication sendAction:to:from:forEvent:] + 96 15 UIKitCore 0x18b4d1ed0 -[UIControl sendAction:to:forEvent:] + 240 16 UIKitCore 0x18b4d2228 -[UIControl _sendActionsForEvents:withEvent:] + 396 17 UIKitCore 0x18b4d124c -[UIControl touchesEnded:withEvent:] + 516 18 UIKitCore 0x18b692f24 _UIGestureEnvironmentUpdate + 7088 19 UIKitCore 0x18b691328 -[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:] + 372 20 UIKitCore 0x18b6910f4 -[UIGestureEnvironment _updateForEvent:window:] + 232 21 UIKitCore 0x18bafcc48 -[UIWindow sendEvent:] + 3440 22 UIKitCore 0x18bad88ec -[UIApplication sendEvent:] + 344 23 UIKitCore 0x18bb59970 dispatchPreprocessedEventFromEventQueue + 6808 24 UIKitCore 0x18bb5c4ec handleEventQueueInternal + 5364 25 UIKitCore 0x18bb54168 handleHIDEventFetcherDrain + 140 26 CoreFoundation 0x18798aad8 CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION + 24 27 CoreFoundation 0x18798aa30 CFRunLoopDoSource0 + 80 28 CoreFoundation 0x18798a1b8 CFRunLoopDoSources0 + 184 29 CoreFoundation 0x1879851e8 CFRunLoopRun + 788 30 CoreFoundation 0x187984ba8 CFRunLoopRunSpecific + 424 31 GraphicsServices 0x191afb344 GSEventRunModal + 160 32 UIKitCore 0x18bac03e4 UIApplicationMain + 1932 33 myapp 0x10271626c main + 24 (DivChangesVC.swift:24) 34 libdyld.dylib 0x18780c8f0 start + 4

crash here line 89<<< drAction.didSelect{(selectedText , index , id) in //update and return if selectedText == "Bought" { self.action = "B" } else if selectedText == "Sold" { self.action = "S" if let s = UserDefaults.standard.string(forKey: "tip_sold"), s == "Y" {

            } else {
                let appearance = SCLAlertView.SCLAppearance(
                    kTitleFont: UIFont(name: "HelveticaNeue", size: 20)!,
                    kTextFont: UIFont(name: "HelveticaNeue", size: 14)!,
                    kButtonFont: UIFont(name: "HelveticaNeue-Bold", size: 12)!,
                    showCloseButton: false,
                    showCircularIcon: false,
                    buttonsLayout: .vertical
                )
                let alertView = SCLAlertView(appearance: appearance)
                alertView.addButton("Ok",backgroundColor: UIColor.gray, textColor: UIColor.white) {
                    return
                }
                alertView.addButton("Don't show again",backgroundColor: UIColor.gray, textColor: UIColor.white) {
                    UserDefaults.standard.set("Y", forKey: "tip_sold")
                    return
                }
                alertView.showSuccess("xx.", subTitle: "", colorStyle: 0x000000, colorTextButton: 0xFFFFFF)
            }
        } else {
            self.action = ""
        }
    }

jriosdev / iOSDropDown

Intermittent crash on closure #92