macos - Swift - OS X 上的 AVFoundation 添加子层问题

Question

我正在尝试在自定义 View 中预览我的视频设备。但我得到的只是一个空窗口。我发现访问相机没有问题。应用程序启动后，我就会看到我的罗技摄像头 LED 亮起。我假设我的问题是将预览图层添加为子图层。

这是我的简单代码:

import Cocoa
import AVFoundation

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {

@IBOutlet weak var video: NSView!
@IBOutlet weak var window: NSWindow!

let captureSession = AVCaptureSession()
var captureDevice : AVCaptureDevice?
var previewLayer : AVCaptureVideoPreviewLayer?

func applicationDidFinishLaunching(aNotification: NSNotification) {

    captureSession.sessionPreset = AVCaptureSessionPresetLow
    let devices = AVCaptureDevice.devices()
    for device in devices {

        if (device.hasMediaType(AVMediaTypeVideo)) {
            captureDevice = device as? AVCaptureDevice
            println(captureDevice)
        }
    }

    if captureDevice != nil {
        beginSession()
    }


}

func beginSession() {

    println("begin")
    var err : NSError? = nil
    captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))

    if err != nil {
        println("error: \(err?.localizedDescription)")
    }



    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    previewLayer!.frame = self.video.bounds
    previewLayer!.videoGravity = AVLayerVideoGravityResizeAspectFill
    self.video.layer?.addSublayer(previewLayer)
    captureSession.startRunning()
}

func applicationWillTerminate(aNotification: NSNotification) {
    // Insert code here to tear down your application
}


}

Answer 1

解决了。在 Interface Builder 中，我需要在核心动画中添加自定义 View 。