swift - *** 由于未捕获的异常 'NSInternalInconsistencyException' 终止应用程序，原因 : 'threading violation: expected the main thread'

Question

我遇到了一个问题，当用户点击个人资料图片将他们的照片上传到应用程序时，我们的应用程序崩溃。应用程序向用户发送授权请求，一旦点击“允许”按钮，就会立即发生崩溃。

也许相关信息是这不是根 View Controller 。注册过程在同一个 Storyboard 上有一系列页面。这发生在我需要请求权限的任何页面上 不是 主根 Controller 。

我试图将 PhotoAuthorization 代码块放入 DispatchQueue.main.async，但这似乎不起作用。这是前开发人员的遗留代码，所以我仍在努力修复一些东西。

疑似应用程序崩溃的代码块:

    func checkPermission() {
        let photoAuthStatus = PHPhotoLibrary.authorizationStatus()
        switch photoAuthStatus {
        case .authorized:
            self.showPhotoActionSheet()
        case .notDetermined:
            PHPhotoLibrary.requestAuthorization({ (newStatus) in
                if newStatus == PHAuthorizationStatus.authorized {
                    self.showPhotoActionSheet()
                }
            })
        case .restricted:
            showPermissionRequestReason()
        case .denied:
            showPermissionRequestReason()
        }
    }

    func showPhotoActionSheet() {
        let actionSheet = YoutubeActionController()
        actionSheet.addAction(Action(ActionData(title: "Take Photo", image: UIImage(named: "ic_photo_camera")!), style: .default, handler: { action in 
            if UIImagePickerController.isSourceTypeAvailable(.camera) {
                self.imagePicker.sourceType = .camera
                self.imagePicker.allowsEditing = true
                self.present(self.imagePicker, animated: true, completion: nil)
            }
        }))
        actionSheet.addAction(Action(ActionData(title: "Choose from Camera Roll", image: UIImage(named: "ic_photo_album")!), style: .default, handler: { action in 
            if UIImagePickerController.isSourceTypeAvailable(.savedPhotosAlbum) {
                self.imagePicker.sourceType = .savedPhotosAlbum
                self.imagePicker.allowsEditing = true
                self.present(self.imagePicker, animated: true, completion: nil)
            }
        }))
        actionSheet.addAction(Action(ActionData(title: "Cancel", image: UIImage(named: "ic_cancel")!), style: .cancel, handler: nil))
        present(actionSheet, animated: true, completion: nil)
    }

找到下面的回溯。任何帮助是极大的赞赏!

2020-01-23 13:39:23.878772+0000 ***[89799:17598462] *** Assertion failure in -[FBSSerialQueue assertOnQueue], /BuildRoot/Library/Caches/com.apple.xbs/Sources/FrontBoardServices_Sim/FrontBoard-626.2/FrontBoardServices/FBSSerialQueue.m:98
2020-01-23 13:39:23.990535+0000 ***[89799:17598462] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'threading violation: expected the main thread'
*** First throw call stack:
(
    0   CoreFoundation                      0x0000000115f7102e __exceptionPreprocess + 350
    1   libobjc.A.dylib                     0x0000000115ddeb20 objc_exception_throw + 48
    2   CoreFoundation                      0x0000000115f70da8 +[NSException raise:format:arguments:] + 88
    3   Foundation                          0x000000010f613b61 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 191
    4   FrontBoardServices                  0x000000011c344a8b -[FBSSerialQueue assertOnQueue] + 236
    5   FrontBoardServices                  0x000000011c2f77b9 -[FBSSceneImpl updateClientSettings:withTransitionContext:] + 70
    6   FrontBoardServices                  0x000000011c2f7a04 -[FBSSceneImpl updateClientSettingsWithTransitionBlock:] + 154
    7   FrontBoardServices                  0x000000011c2f7929 -[FBSSceneImpl updateClientSettingsWithBlock:] + 110
    8   UIKitCore                           0x00000001200c7aa0 -[FBSScene(UIApp) updateUIClientSettingsWithBlock:] + 160
    9   UIKitCore                           0x000000011fcbf5f6 -[_UISystemAppearanceManager updateScreenEdgesDeferringSystemGestures] + 374
    10  UIKitCore                           0x000000011ff229e2 __70-[UIViewController setNeedsUpdateOfScreenEdgesDeferringSystemGestures]_block_invoke_2 + 118
    11  UIKitCore                           0x000000011ff00cb5 -[UIViewController _updateSystemAppearanceWithRecursionBlock:action:] + 295
    12  UIKitCore                           0x000000011ff22629 -[UIViewController _setPresentedStatusBarViewController:] + 220
    13  UIKitCore                           0x000000011ff129c3 -[UIViewController _presentViewController:modalSourceViewController:presentationController:animationController:interactionController:completion:] + 1381
    14  UIKitCore                           0x000000011ff143c6 -[UIViewController _presentViewController:withAnimationController:completion:] + 4349
    15  UIKitCore                           0x000000011ff16c47 __63-[UIViewController _presentViewController:animated:completion:]_block_invoke + 98
    16  UIKitCore                           0x000000011ff1715f -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 511
    17  UIKitCore                           0x000000011ff16ba5 -[UIViewController _presentViewController:animated:completion:] + 187
    18  UIKitCore                           0x000000011ff16e0c -[UIViewController presentViewController:animated:completion:] + 150
    19  ***                      0x000000010dc472ca $s14***26RegistrationViewControllerC20showPhotoActionSheetyyF + 2522
    20  ***                      0x000000010dc462b9 $s14***26RegistrationViewControllerC15checkPermissionyyFySo21PHAuthorizationStatusVcfU_ + 201
    21  ***                      0x000000010dc46355 $sSo21PHAuthorizationStatusVIegy_ABIeyBy_TR + 53
    22  Photos                              0x0000000116a72643 __39+[PHPhotoLibrary requestAuthorization:]_block_invoke + 52
    23  AssetsLibraryServices               0x000000013927ff7e __79-[PLPrivacy _isPhotosAccessAllowedWithScope:forceHandler:accessAllowedHandler:]_block_invoke.14 + 501
    24  AssetsLibraryServices               0x000000013924b60c __pl_dispatch_async_block_invoke + 25
    25  libdispatch.dylib                   0x0000000117a02848 _dispatch_call_block_and_release + 12
    26  libdispatch.dylib                   0x0000000117a037b9 _dispatch_client_callout + 8
    27  libdispatch.dylib                   0x0000000117a09526 _dispatch_lane_serial_drain + 707
    28  libdispatch.dylib                   0x0000000117a09f5c _dispatch_lane_invoke + 388
    29  libdispatch.dylib                   0x0000000117a13ff9 _dispatch_workloop_worker_thread + 626
    30  libsystem_pthread.dylib             0x00007fff51bfd611 _pthread_wqthread + 421
    31  libsystem_pthread.dylib             0x00007fff51bfd3fd start_wqthread + 13
)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

该错误告诉您要执行以下操作:

reason: 'threading violation: expected the main thread'

很多时候，当你传递一个闭包时，你可能会在后台线程上被回调。但是，如果您想对 UI 执行任何操作，则必须在主线程上完成。我们使用 DispatchQueue.main.async将一个块传递给主队列并使其在主线程上异步运行，

在

PHPhotoLibrary.requestAuthorization({ (newStatus) in
    if newStatus == PHAuthorizationStatus.authorized {
        self.showPhotoActionSheet()
    }
})    

您需要分派(dispatch)到主线程

PHPhotoLibrary.requestAuthorization({ (newStatus) in
    if newStatus == PHAuthorizationStatus.authorized {
        DispatchQueue.main.async {
            self.showPhotoActionSheet()
        }

    }
})    

看起来您可能在后台调用 checkPermission 。如果是这样，您还需要将调用包装到:

self.showPhotoActionSheet()

从调用堆栈 - 看起来这可能是您遇到问题的那个。