帶有藥丸形狀UIButton擺動影片的奇怪行為

我的視圖有一個 UIButton，它是通過將角半徑設定為視圖高度的一半而形成的藥丸形狀。一切都很好，但是當它影片（通過旋轉擺動）時，角半徑似乎發生了變化，使藥丸形狀變形。當影片結束時一切恢復正常：

正常外觀：

影片外觀（見圓角半徑）：

此處顯示了此記錄：

https://www.dropbox.com/s/xoowpfzdf0ijuql/Simulator Screen Recording - iPhone 12 - 2021-10-08 at 15.05.14.mp4?dl=0

影片代碼 (Xamarin c#) 如下所示：

public static void Wiggle(UIView view, double duration = 0.1f, float repeatCount = 3.0f)
{
    UIView.Animate(duration,
        () => view.Transform = CGAffineTransform.MakeRotation((nfloat)(-5f * Math.PI / 180f)),
        () =>
        {
            UIView.AnimateNotify(duration, 0.0f, UIViewAnimationOptions.Repeat | UIViewAnimationOptions.Autoreverse | UIViewAnimationOptions.AllowUserInteraction,
                () =>
                {
                    UIView.SetAnimationRepeatCount(repeatCount);
                    view.Transform = CGAffineTransform.MakeRotation((nfloat)(5f * Math.PI / 180f));
                },
                (animationFinished) =>
                {
                    UIView.Animate(duration, 0, UIViewAnimationOptions.AllowUserInteraction,
                        () => { view.Transform = CGAffineTransform.MakeIdentity(); }, null);
                });
        });
}

正如視頻中所見，它并不總是發生。有時藥丸形狀仍然存在。它發生在模擬器和真實設備上。有什么線索嗎？謝謝

uj5u.com熱心網友回復：

你不顯示你的“PillShape”的代碼，但我假設你是“圓角半徑設定為半視圖高度”的LayoutSubviews()？

如果是這樣，問題很可能是當您旋轉按鈕時，它的高度會發生變化，并且您不再具有正確的半徑。

您最好使用圖層影片，而不是旋轉視圖本身。

我不使用 Xamarin/C#，所以這是基于 Objective-C 代碼......希望它能讓你走上正軌。

這使用了一個緩慢（0.5 秒）的影片，可以很容易地看到半徑在旋轉程序中不會改變。點擊按鈕開始/停止影片：

using Foundation;
using System;
using UIKit;
using CoreAnimation;
using ObjCRuntime;

namespace QuickTestApp
{
    public partial class ViewController : UIViewController
    {
        public WigglePillButton btn { get; private set; }
        public bool isWiggling { get; private set; }

        public ViewController(IntPtr handle) : base(handle)
        {
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            // Perform any additional setup after loading the view, typically from a nib.

            btn = new WigglePillButton();
            btn.TranslatesAutoresizingMaskIntoConstraints = false;

            btn.SetTitle("Testing", UIControlState.Normal);
            btn.BackgroundColor = UIColor.SystemBlueColor;

            View.AddSubview(btn);

            // Get the parent view's layout
            var margins = View.SafeAreaLayoutGuide;

            btn.CenterXAnchor.ConstraintEqualTo(margins.CenterXAnchor).Active = true;
            btn.CenterYAnchor.ConstraintEqualTo(margins.CenterYAnchor).Active = true;
            btn.WidthAnchor.ConstraintEqualTo(120).Active = true;

            btn.AddTarget(this, new Selector("ButtonClickAction:"), UIControlEvent.TouchUpInside);

            isWiggling = false;
        }

        [Export("ButtonClickAction:")]
        public void ButtonClickAction(UIButton sender)
        {
            if (isWiggling)
            {
                btn.StopAnim();
            } else {
                btn.StartAnim();
            }
            isWiggling = !isWiggling;
        }

        public override void DidReceiveMemoryWarning()
        {
            base.DidReceiveMemoryWarning();
            // Release any cached data, images, etc that aren't in use.
        }
    }

    public class WigglePillButton : UIButton
    {
        public override void LayoutSubviews()
        {
            base.LayoutSubviews();
            var maskingShapeLayer = new CAShapeLayer()
            {
                Path = UIBezierPath.FromRoundedRect(Bounds, 12).CGPath
            };
            Layer.Mask = maskingShapeLayer;
        }

        public void StartAnim()
        {
            AddAnimations();

        }

        public void StopAnim()
        {
            Layer.RemoveAllAnimations();

        }

        private void AddAnimations()
        {
            CATransaction.Begin();

            Layer.AddAnimation(RotAnim(), "rot");

            CATransaction.Commit();

        }

        private CAKeyFrameAnimation RotAnim()
        {
            CAKeyFrameAnimation animation = CAKeyFrameAnimation.FromKeyPath("transform.rotation.z");
            double angle = 5f * Math.PI / 180f;
            animation.Values = new[] { NSNumber.FromDouble(angle), NSNumber.FromDouble(-angle) };
            animation.AutoReverses = true;
            animation.Duration = 0.5;
            animation.RepeatCount = float.PositiveInfinity;
            return animation;
        }

    }
}

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