ARKit -[UIView setAnimationsEnabled:] 不支持从后台线程对 UIView 或子类执行任何操作

Question

我有一个 ViewController，里面有一个 collectionView。我在 ARSCNView 中显示 collectionView 单元格的内容。

当我将 ViewController 的视图属性设置为 Material 的 content property 时，我从问题中得到了错误。

material.diffuse.contents = self.myViewController.view // produces error and sometimes it crashes. When it does't crash I can see the collectionView fine but the error is still there

我知道是 vc 的 view property 导致了问题，因为当我尝试设置 vc 而不使用它的视图属性时出现错误离开。问题是我再也看不到场景中的 vc。

material.diffuse.contents = self.myViewController // produces no error but the collectionView is no longer visible.

如何在 mainQueue 上设置 vc 的视图属性来避免这个问题？

same problem happened这个人。

我的代码（除了委托方法，这是 class 中的所有代码）：

MyViewController: UIViewController, ...CollectionViewDataSource && Delegate {

    lazy var collectionView: UICollectionView = {
        // create collectionView
    }()

    var dataSource = ["0", "1", "2", "3", "4" ...]

    override func viewDidLoad() {
        super.viewDidLoad()

        DispatchQueue.main.async {

            self.view.backgroundColor = UIColor.clear

            self.view.addSubview(collectionView)
            // set its anchors
        }
    }
}

ClassWithSceneKit:

lazy var sceneView: ARSCNView = { ... }()

let myVC = MyViewController()

override func viewDidLoad() {
    super.viewDidLoad()

    DispatchQueue.main.async  {

        self.myVC.tableData.append("9")
        self.myVC.tableData.append("10")
        self.myVC.tableData.append("11")
        self.myVC.collectionView.reloadData()

        self.myVC.view.isOpaque = false // the background is clear, look in the picture I attached

        let material = SCNMaterial()
        material.diffuse.contents = self.myVC.view // ** this is the line causing the problem ***

        let plane = SCNPlane(width: 0.5, height: 0.7)
        plane.materials = [material]
        plane.cornerRadius = 0.015

        let node = SCNNode()
        node.geometry = plane
        node.position = SCNVector3(0.36, 0.12, -0.8)

        self.sceneView.scene.rootNode.addChildNode(node)
    }
}

ARKit_4[20429:4746699] [Animation] +[UIView setAnimationsEnabled:] being called from a background thread. Performing any operation from a background thread on UIView or a subclass is not supported and may result in unexpected and insidious behavior.

trace=(
    0   UIKitCore                           0x000000019a855fa4 B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 15241124
    1   libdispatch.dylib                   0x0000000103356bd8 _dispatch_client_callout + 16
    2   libdispatch.dylib                   0x00000001033584c8 _dispatch_once_callout + 84
    3   UIKitCore                           0x000000019a855f08 B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 15240968
    4   UIKitCore                           0x000000019a856090 B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 15241360
    5   UIKitCore                           0x0000000199b9d030 B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 1900592
    6   UIKitCore                           0x000000019a5fdd0c B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 12782860
    7   UIKitCore                           0x000000019a40462c B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 10712620
    8   UIKitCore                           0x000000019a5fbaa4 B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 12774052
    9   UIKitCore                           0x000000019a401b8c B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 10701708
    10  UIKitCore                           0x000000019a4029ac B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 10705324
    11  UIKitCore                           0x000000019a402710 B7E79AF1-F09F-3BCE-B073-ECEA027BC0E8 + 10704656
    12  SceneKit                            0x00000001aa496864 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 2283620
    13  SceneKit                            0x00000001aa4969c8 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 2283976
    14  SceneKit                            0x00000001aa4b67d8 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 2414552
    15  SceneKit                            0x00000001aa329168 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 786792
    16  SceneKit                            0x00000001aa2f94c8 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 591048
    17  SceneKit                            0x00000001aa2f93f0 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 590832
    18  SceneKit                            0x00000001aa31c0f0 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 733424
    19  SceneKit                            0x00000001aa31935c 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 721756
    20  SceneKit                            0x00000001aa31809c 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 716956
    21  SceneKit                            0x00000001aa31700c 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 712716
    22  SceneKit                            0x00000001aa43f878 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1927288
    23  SceneKit                            0x00000001aa43f5cc 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1926604
    24  SceneKit                            0x00000001aa44684c 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1955916
    25  SceneKit                            0x00000001aa2d2554 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 431444
    26  SceneKit                            0x00000001aa2d3ea4 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 437924
    27  SceneKit                            0x00000001aa3cbe28 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1453608
    28  SceneKit                            0x00000001aa3cc694 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1455764
    29  SceneKit                            0x00000001aa3ccc00 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1457152
    30  SceneKit                            0x00000001aa3ccf94 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1458068
    31  SceneKit                            0x00000001aa4672f0 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 2089712
    32  ARKit                               0x00000001b176d104 4003283E-C369-3DBD-A6D1-3D04690F6674 + 958724
    33  SceneKit                            0x00000001aa32d8d0 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 805072
    34  SceneKit                            0x00000001aa432b1c 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1874716
    35  libdispatch.dylib                   0x0000000103356bd8 _dispatch_client_callout + 16
    36  libdispatch.dylib                   0x0000000103365858 _dispatch_lane_barrier_sync_invoke_and_complete + 124
    37  SceneKit                            0x00000001aa432aac 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 1874604
    38  GPUToolsCore                        0x000000010357d5f8 -[DYDisplayLinkInterposer forwardDisplayLinkCallback:] + 168
    39  QuartzCore                          0x000000019cc72860 8705A7FE-6FD6-301F-BE30-D32F13CB6C0E + 71776
    40  IOKit                               0x00000001972a4930 IODispatchCalloutFromCFMessage + 488
    41  CoreFoundation                      0x00000001962ba670 FF63481D-FB6A-353B-B2C1-AC4EAECF594D + 525936
    42  CoreFoundation                      0x00000001962e3e40 FF63481D-FB6A-353B-B2C1-AC4EAECF594D + 695872
    43  CoreFoundation                      0x00000001962e356c FF63481D-FB6A-353B-B2C1-AC4EAECF594D + 693612
    44  CoreFoundation                      0x00000001962de440 FF63481D-FB6A-353B-B2C1-AC4EAECF594D + 672832
    45  CoreFoundation                      0x00000001962dd8a0 CFRunLoopRunSpecific + 464
    46  Foundation                          0x000000019661d824 3C682044-3249-3938-8111-F2F12D066D2B + 30756
    47  SceneKit                            0x00000001aa32dcac 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 806060
    48  SceneKit                            0x00000001aa32def4 5DCB330E-65B4-3BA3-8648-D7BB0F7849CC + 806644
    49  libsystem_pthread.dylib             0x00000001960821d0 _pthread_start + 124
    50  libsystem_pthread.dylib             0x0000000196085ae0 thread_start + 8
)

Answer 1

我根据 Playing GIF using GIFU library in SceneKit causes app UI freeze any solution? UIView Animated being called from a background thread 使用 view.layer 而不是 view 解决了类似的问题：

material.diffuse.contents = self.myVC.view.layer

Answer 2

我联系了 Apple，他们说目前不支持此功能。他们根据保密协议向我发送了信息，因此我无法详细说明。

他们确实说过，如果这是我想要的功能，我可以向他们的团队发送请求，看看他们是否会考虑添加它。

Answer 3

当我将 SwiftUI view 包装到 HostingViewController 并将其传递给 SCNNode.material.diffuse.contents 时，我遇到了非常相似的问题。问题是，在 iOS15 之后，只显示视图的第一个快照 - 没有动画，没有交互。

我尝试了很多解决方法，例如每秒将 view 渲染到 Image 30 次并将其传递给 SCNNode，但没有任何效果。

我最终计算了透视变换矩阵并在 view 上应用了 CATransform3D。

现在很有魅力。

ARKit -[UIView setAnimationsEnabled:] 不支持从后台线程对 UIView 或子类执行任何操作

ARKit -[UIView setAnimationsEnabled:] Performing any operation from a background thread on UIView or a subclass is not supported

grand-central-dispatch

ios

uicollectionview

swift

arkit