Приложение iOS вылетает при касании экрана для автофокусировки в камере ⇐ IOS

[Anonymous]

In my app I am scanning QR codes using camera, In case if user touches screen it should autofocus at that point but sometimes app crashes. Here is code for that function in which app crashes at code line device.focusPointOfInterest = focusPoint

/** Touch the screen for autofocus */ public override func touchesBegan(_ touches: Set, with event: UIEvent?) { guard touches.first?.view == view, let touchPoint = touches.first, let device = videoCaptureDevice else { return } let videoView = view let screenSize = videoView!.bounds.size let xPoint = touchPoint.location(in: videoView).y / screenSize.height let yPoint = 1.0 - touchPoint.location(in: videoView).x / screenSize.width let focusPoint = CGPoint(x: xPoint, y: yPoint) do { try device.lockForConfiguration() } catch { return } // Focus to the correct point, make continiuous focus and exposure so the point stays sharp when moving the device closer device.focusPointOfInterest = focusPoint device.focusMode = .continuousAutoFocus device.exposurePointOfInterest = focusPoint device.exposureMode = AVCaptureDevice.ExposureMode.continuousAutoExposure device.unlockForConfiguration() } Logs for crashes (only relevant part is attached)

Last Exception Backtrace: 0 CoreFoundation 0x180f37c60 __exceptionPreprocess + 216 (NSException.m:200) 1 libobjc.A.dylib 0x198767ee4 objc_exception_throw + 56 (objc- exception.mm:565) 2 AVFCapture 0x1a45297f4 -[AVCaptureFigVideoDevice setFocusPointOfInterest:] + 276 (AVCaptureFigVideoDevice.m:0) 3 QR Code Creator Scanner 0x1021f13bc specialized CodeScannerView.ScannerViewController.touchesBegan(_:with:) + 508 (CodeScannerView.swift:307) 4 QR Code Creator Scanner 0x1021f010c CodeScannerView.ScannerViewController.touchesBegan(_:with:) + 12 (:0) 5 QR Code Creator Scanner 0x1021f010c @objc CodeScannerView.ScannerViewController.touchesBegan(_:with:) + 120 6 UIKitCore 0x1833c099c forwardTouchMethod + 316 (UIResponder.m:2039) 7 UIKitCore 0x183341ed0 -[UIWindow _sendTouchesForEvent:] + 624 (UIWindow.m:2960) The Line of code causing crash is

device.focusPointOfInterest = focusPoint I am not ale to understand actual reason of crash.


Источник: https://stackoverflow.com/questions/781 ... -in-camera