视图加载后在视图上设置角半径

Question

我有一个来自班级的视图，我想将角半径设置为宽度的一半。

宽度是使用自动布局生成的计算属性。所以通常我会像这样在viewWillLayoutSubviews() 中设置圆角半径属性

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()

    c.largeProfileImage.layer.cornerRadius = c.largeProfileImage.frame.width / 2
}

但 largeProfileImage 不是在 viewdidLoad 之后调用的初始视图，我通过点击手势对其进行动画处理。下面是视图在屏幕上动画的位置。它是在同一个函数中创建的。

     //I tried setting the cornerRadius here as well but it isn't setting.

    //c.largeProfileImage.layer.cornerRadius = c.largeProfileImage.frame.width / 2


    self.view.layoutIfNeeded()

    UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0, options: .curveEaseOut, animations: {

        self.profileImageContainerCenterY?.constant = -(c.profileImageContainer.frame.height) * 2
        self.profileSettingsContainerCenterY?.constant = 0

        c.profileSettingsContainer.alpha = 1
        c.largeProfileImage.alpha = 1

        self.view.layoutIfNeeded()
    }, completion: { (completed) in
        self.view.layoutIfNeeded()
})

编辑：

这是个人资料图片

let largeProfileImage: UIImageView = {
    let pv = UIImageView()
    pv.contentMode = .scaleAspectFill
    pv.layer.masksToBounds = true
    pv.clipsToBounds = true
    pv.image = UIImage(named: "user")

    pv.translatesAutoresizingMaskIntoConstraints = false
    return pv
}()

Answer 1

我能够成功调试问题。

由于宽度是一个计算属性，所以在布局布局之前它是 0，这意味着

c.largeProfileImage.layer.cornerRadius = c.largeProfileImage.frame.width / 2

self.view.layoutIfNeeded()

导致圆角半径为零。

所以解决方案...

是在之后调用宽度是在计算宽度之后设置拐角半径。

self.view.layoutIfNeeded()

c.largeProfileImage.layer.cornerRadius = c.largeProfileImage.frame.width / 2

Answer 2

为了正确的动画改变这样的顺序。

    self.profileImageContainerCenterY?.constant = -(c.profileImageContainer.frame.height) * 2
    self.profileSettingsContainerCenterY?.constant = 0
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0, options: .curveEaseOut, animations: {
    c.profileSettingsContainer.alpha = 1
    c.largeProfileImage.alpha = 1
    self.view.layoutIfNeeded()
}, completion: nil)

Answer 3

下面三行是获得圆形图像所必需的-

image.layer.cornerRadius = image.frame.width / 2
image.layer.masksToBounds = false
image.clipsToBounds = true

您可能会看到圆形的UIImage，但您也可能会注意到圆圈内的方形图像，并解决您可能玩过contentMode 的问题。大多数时候.scaleAspectFill 完成这项工作。