类型“ CAGradientLayerType”（也称为“ NSString”）没有成员“圆锥”

Question

我正在尝试使用新的conic gradient type。我已将部署目标设置为12.0并添加了QuartzCore框架，并且将渐变类型设置为.conic：

    let gradient = CAGradientLayer()
    gradient.type = CAGradientLayerType.conic

我什至可以点击查看文档：

extension CAGradientLayerType {
    ...

    /* Conic gradient. The gradient is centered at 'startPoint' and its 0-degrees
     * direction is defined by a vector spanned between 'startPoint' and
     * 'endPoint'. When 'startPoint' and 'endPoint' overlap the results are
     * undefined. The gradient's angle increases in the direction of rotation of
     * positive x-axis towards positive y-axis. */

    @available(iOS 12.0, *)
    public static let conic: CAGradientLayerType
}

但我仍然遇到此构建错误：

Type 'CAGradientLayerType' (aka 'NSString') has no member 'conic'

Answer 1

感谢this answer，看来问题出在我的快速语言版本（“目标”>“构建设置”>“快速语言版本”）。要使用此语法，必须为版本5。否则，我想我们需要将该属性视为字符串，并将其设置为kCAGradientLayerConic。