Question

我有以下代码来旋转UIView 360度。它是UIView的扩展文件。

extension NSView {
func rotate360Degrees(duration: CFTimeInterval = 0.5, completionDelegate: AnyObject? = nil) {
    let rotateAnimation = CABasicAnimation(keyPath: "transform.rotation")
    rotateAnimation.fromValue = 0.0
    rotateAnimation.toValue = CGFloat(M_PI * 2.0)
    rotateAnimation.duration = duration

    if let delegate: AnyObject = completionDelegate {
        rotateAnimation.delegate = delegate
    }
    self.layer.addAnimation(rotateAnimation, forKey: nil)

}
}

单击按钮后，我使用refreshButton.rotate360Degrees()开始动画。

我想为NSView重新创建它，但它似乎没有使用上面的代码。感谢

Answer 1

它有效，但你必须改变两件事：

extension NSView {
    func rotate360Degrees(duration: CFTimeInterval = 0.5, completionDelegate: AnyObject? = nil) {
        let rotateAnimation = CABasicAnimation(keyPath: "transform.rotation")
        rotateAnimation.fromValue = 0.0
        rotateAnimation.toValue = CGFloat(M_PI * 2.0)
        rotateAnimation.duration = duration
        if let delegate: AnyObject = completionDelegate {
            rotateAnimation.delegate = delegate
        }
        // `addAnimation` will execute *only* if the layer exists
        self.layer?.addAnimation(rotateAnimation, forKey: nil)
    }
}

在?之后添加self.layer，以便在图层不可用时允许条件执行。

如果您愿意，可以使用if let ...：

    if let theLayer = self.layer {
        theLayer.addAnimation(rotateAnimation, forKey: nil)
    }

为您的视图设置wantsLayer为true，以强制视图为图层备份（视图不会在OS X上自动进行图层备份）。

旋转NSView 360度

1 个答案: