Ios 通过编程方式在AVCaptureVideoPreviewLayer上添加UIButton

我正在尝试在

AVCaptureVideoPreviewLayer

上创建一个覆盖

我尝试了以下操作，但结果与我预期的不同，因为按钮的标题不可见：

let previewLayer: AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: self.avCaptureSession)
previewLayer.frame = self.view.layer.frame
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
self.view.layer.addSublayer(previewLayer)



//Add Button
let captureButton = UIButton(frame: CGRectMake(0, 0, 100 , 100))
captureButton.backgroundColor = UIColor.grayColor()
captureButton.setTitle("Capture", forState: .Normal)
captureButton.setTitleColor(UIColor.redColor(), forState: .Normal)
captureButton.addTarget(self, action: "actionCapture:", forControlEvents: .TouchDragInside)

previewLayer.addSublayer(captureButton.layer)

以下是当前状态的屏幕截图：

---

您应该将

预览层

添加到单独视图的子层。这样，您就可以轻松地在主视图上方添加其他子视图

let previewView = UIView(frame: view.frame)
view.addSubview(previewView)

previewView.layer.addSublayer(previewLayer)

[...]

view.addSubview(captureButton)

---

您应该将

previewLayer

添加到单独视图的子层。这样，您就可以轻松地在主视图上方添加其他子视图

let previewView = UIView(frame: view.frame)
view.addSubview(previewView)

previewView.layer.addSublayer(previewLayer)

[...]

view.addSubview(captureButton)

---

结果如何？你能给我们看一张截图吗？@我已经添加了截图。结果如何？你能给我们看一张截图吗？@我已经添加了截图。