我正在将QLPreviewController添加为我的viewcontroller中的子视图。下面是添加代码。

    self.previewController = QLPreviewController()
    previewController.dataSource = self
    //present(previewController,animated: true)
    previewController.view.frame = self.previewLayer.bounds
    self.previewLayer.addSubview(previewController.view)
    previewController.didmove(toParent: self)
    self.view.layoutIfNeeded()

当我拍摄屏幕截图时，屏幕上的所有内容都会被捕获，而不是QLPreviewController（正在显示xls表） 我尝试了多种捕获屏幕结果的方法，每次的结果几乎相同。

extension UIApplication {
var screenshot: UIImage? {
    UIGraphicsBeginImageContextWithOptions(UIScreen.main.bounds.size,false,0)
    guard let context = UIGraphicsgetcurrentContext() else { return nil }
    for window in windows {
        window.layer.render(in: context)
    }
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
}
}
        DispatchQueue.main.async {
        let screenshot = UIApplication.shared.screenshot
        UIImageWriteToSavedPhotosAlbum(screenshot!,nil,nil)
    }