Swift无法将类型“ CGPath”的值分配给类型“ CGPath？”

Question

I'm attempting to round just the top left and bottom left corners of a UITextField . Here is the code I am using:

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    let maskLayer = CAShapeLayer()
    maskLayer.path = UIBezierPath(roundedRect: locationText.bounds, byRoundingCorners: .TopLeft | .BottomLeft, cornerRadii: CGSize(width: 10.0, height: 10.0)).CGPath

    locationText.layer.mask = maskLayer;
}

The line

maskLayer.path = UIBezierPath(roundedRect: locationText.bounds, byRoundingCorners: .TopLeft | .BottomLeft, cornerRadii: CGSize(width: 10.0, height: 10.0)).CGPath

is producing the error

Cannot assign a value of type 'CGPath' to a value of type 'CGPath?'

This is confusing me since I've been able to set values to optionals no problem elsewhere in the code. Could someone help me understand what I am doing wrong?

Answer 1

如果您将Swift 2.0与Xcode Beta一起使用，则可能是编译器的一个错误，试图告诉您应该使用数组来指示拐角

maskLayer.path = UIBezierPath(roundedRect: self.view.bounds, byRoundingCorners: [.TopLeft, .BottomLeft], cornerRadii: CGSize(width: 10.0, height: 10.0)).CGPath