我花了一段时间尝试解决这个问题,但我做不到。我可能在这里错过了一些非常简单的事情。我正在尝试为从底部进入的视图设置动画。这是我用于视图的代码:
private let undoView: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
view.backgroundColor = .white
view.layer.cornerRadius = 15
view.layer.shadowOffset = .zero
view.layer.shadowOpacity = 0.3
view.layer.shadowRadius = 5
view.layer.shouldRasterize = true
view.layer.rasterizationScale = UIScreen.main.scale
let button = UIButton()
button.translatesAutoresizingMaskIntoConstraints = false
button.setTitle("Undo", for: .normal)
button.titleLabel?.textAlignment = .center
button.setTitleColor(.systemBlue, for: .normal)
let buttonConstraints = [
button.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16),
button.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16),
button.topAnchor.constraint(equalTo: view.topAnchor, constant: 16),
button.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -16)
]
view.addSubview(button)
NSLayoutConstraint.activate(buttonConstraints)
let swipeGesture = UISwipeGestureRecognizer(target: view, action: #selector(undoViewSwiped))
view.addGestureRecognizer(swipeGesture)
return view
}()
这是我用来尝试实现动画的代码:
func addUndoView() {
var bottomConstraint = undoView.topAnchor.constraint(equalTo: view.bottomAnchor, constant: 0)
let constraints = [
undoView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
undoView.widthAnchor.constraint(equalToConstant: view.bounds.width / 3),
bottomConstraint,
undoView.heightAnchor.constraint(equalToConstant: 50)
]
view.addSubview(undoView)
NSLayoutConstraint.activate(constraints)
undoView.layoutIfNeeded()
bottomConstraint.isActive = false
bottomConstraint = undoView.topAnchor.constraint(equalTo: view.layoutMarginsGuide.bottomAnchor, constant: -58)
bottomConstraint.isActive = true
UIView.animate(withDuration: 0.5, delay: 0.2, animations: {
self.undoView.layoutIfNeeded()
})
}
我希望该视图仅在可见视图下创建,然后向上滑动至底部布局边距上方的8。但是,此代码仅使视图在其最终位置“展开”,而不是从底部进入视图。由于某种原因,使用self.view.layoutIfNeeded()可使视图从屏幕左上方飞入。
答案 0 :(得分:1)
好的,我通常使用transform属性将一个视图从x位置移到y部分,请检查此示例。
class ViewController: UIViewController {
let button : UIButton = {
let button = UIButton(type: .custom)
button.setTitle("Button", for: .normal)
button.backgroundColor = .gray
button.translatesAutoresizingMaskIntoConstraints = false
return button
}()
let customView : UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
view.backgroundColor = .red
return view
}()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
view.addSubview(button)
view.addSubview(customView)
NSLayoutConstraint.activate([
button.centerYAnchor.constraint(equalTo: self.view.centerYAnchor),
button.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
customView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
customView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
customView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
customView.heightAnchor.constraint(equalToConstant: 100)
])
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
setupAnimationCustomView()
}
private func setupAnimationCustomView(){
UIView.animate(withDuration: 1, delay: 0 , options: .curveEaseOut, animations: {
print(self.button.frame.origin.y)
let translationY = self.view.frame.height - self.button.frame.origin.y - self.button.frame.height - self.customView.frame.height - 8
self.customView.transform = CGAffineTransform(translationX: 0, y: translationY * (-1))
}, completion: nil)
}
}
在动画上,我计算了移动customView所需的距离。