快照UIView会导致应用NSInvalidArgumentException`导致应用程序崩溃“ [_UIReplicantView _isSymbolImage]：无法识别的选择器已发送至实例”

Question

[大家好，我刚刚从App Store将XCode更新到版本11.4，当我尝试在iOS 13.4上对UIView进行快照时，如下所示：

extension UIView {

    func snapshot(at scale: CGFloat) -> UIImage? {

        let renderer = UIGraphicsImageRenderer(size: bounds.size)
        let image = renderer.image { [weak self] context in
            self?.drawHierarchy(in: self?.bounds ?? .zero, afterScreenUpdates: true)
        }

        return image
    }
}

或类似的：

extension UIView {

    func snapshotOld(at scale: CGFloat) -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(bounds.size, false, scale)
        guard let currentContext = UIGraphicsGetCurrentContext() else { return nil }
        layer.render(in: currentContext)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

并像这样将生成的图像设置为UIImageView：

class ViewController: UIViewController {

    @IBOutlet private weak var imageView: UIImageView!


    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        let image = view.snapshot
        imageView.image = image
    }
}

extension UIView {

    @objc var snapshot: UIImage? {
        snapshot(at: 3.0)
//        snapshotOld(at: 3.0)
    }
}

我得到：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[_UIReplicantView _isSymbolImage]: unrecognized selector sent to instance 0x115907c00'
*** First throw call stack:
(0x1ad52c164 0x1ad240c1c 0x1ad42a7e0 0x1b16a5b6c 0x1ad53085c 0x1ad532b60 0x1b1af6cdc 0x1b1af714c 0x1b1af0b30 0x1025061a8 0x102506270 0x1b1010880 0x1b10112cc 0x1b0f25658 0x1b167fc10 0x1b166f13c 0x1b16a088c 0x1ad4a6c54 0x1ad4a18e4 0x1ad4a1d84 0x1ad4a1660 0x1b78b2604 0x1b167615c 0x102507f78 0x1ad31d1ec)
libc++abi.dylib: terminating with uncaught exception of type NSException

我在模拟器和真实设备上都得到了。

你们知道为什么会这样吗？我怀疑这是XCode 11.4错误，因为此代码在较旧的版本上效果很好🤔

Here is a sample project if you would like to try it out on your machine

Answer 1

您没有调用您认为的方法。您有两种选择：

• 将snapshot各处更改为snapshott（或其他明确的替代方法。

• 否则，删除@objc名称。

做任何一件事情，一切都会好起来的。