Ios 如何在自定义UIView（故事板Swift）中居中VideoPreviewLayer

如何在现有UIView中居中放置视频预览播放器？？我试过以下方法，但比我想要的要小

        var videoPreviewLayer : AVCaptureVideoPreviewLayer?

        let captureDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back)
        do {
            let input = try AVCaptureDeviceInput(device: captureDevice!)
            captureSession = AVCaptureSession()
            captureSession?.addInput(input)
            videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession!)
//            let frame : CGRect = self.scanView.layer.bounds
//            videoPreviewLayer?.frame = frame
            videoPreviewLayer?.frame = self.scanView.bounds
//            videoPreviewLayer?.bounds = self.view.bounds

            scanView.layer.addSublayer(videoPreviewLayer!)
            captureSession?.startRunning()
        } catch {
            print("error-jz")
        }

        capturePhotoOutput = AVCapturePhotoOutput()
        capturePhotoOutput?.isHighResolutionCaptureEnabled = true
        captureSession?.addOutput(capturePhotoOutput!)```

---

它应该在您添加videoPreviewLayer的任何视图中居中。但是，当您说它比您想要的小时，可能是因为您没有为播放器层设置视频重力

videoPreviewLayer.videoGravity = .resizeAspectFill

这将使视频预览填满它包含的整个视图。如果它仍然没有按您希望的方式居中，您可能必须修复

ui视图本身的居中