Swift 中没有动画的初始子视图旋转

Question

我想在子视图中有一个缩放动画（在本例中它是一个 UILabel），但设置初始旋转而不设置动画。问题是它从初始旋转回到 0 度。

        recordedTime?.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)

        recordedTime?.transform = CGAffineTransform(rotationAngle: 90 * (.pi/180))

        view.addSubview(recordedTime!)

        UIView.animate(withDuration: 0.50, delay: 0.0, options: [], animations: {

            recordedTime?.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)

        }, completion:nil)

我想我可以在动画中重复旋转变换，但这似乎是多余的，而且我的实际代码更复杂，因为它会检查我的屏幕方向，所以我不想再次重复该代码。

Answer 1

I suppose I could repeat the rotation transform in the animation, but that seems redundant

但这并不多余。由于视图的旋转和缩放在相同的 transform 属性中编码，您别无选择：您必须始终设置 transform 属性以包括旋转和缩放你想要的。

您可以创建属性来分别存储旋转和缩放，然后根据这些属性计算 transform：

class ViewController: UIViewController {

    @IBOutlet var recordedTime: UILabel!

    private var recordedTimeRotation: CGFloat = 0 {
        didSet { updateRecordedTimeTransform() }
    }

    private var recordedTimeScale: CGFloat = 1 {
        didSet { updateRecordedTimeTransform() }
    }

    private func updateRecordedTimeTransform() {
        var transform: CGAffineTransform = .identity
        transform = transform.rotated(by: recordedTimeRotation)
        transform = transform.scaledBy(x: recordedTimeScale, y: recordedTimeScale)
        recordedTime?.transform = transform
    }

    private func run() {
        recordedTimeScale = 0.1
        recordedTimeRotation = .pi / 2
        view.addSubview(recordedTime!)

        UIView.animate(withDuration: 0.50, delay: 0.0, options: [], animations: {
            recordedTimeScale = 1
        }, completion:nil)
    }

}

Swift 中没有动画的初始子视图旋转

Initial subview rotation without animation in Swift

animation

rotation

uiview

uilabel

swift