从这段代码中,除了mainViewConstraint之外,所有的东西都可以很好地进行动画。我试图通过将mainViewConstraint坐标从-195转换为0来使mainView从顶部滑入。不幸的是,它没有从-195移动到0。它从0开始出现。
import UIKit
class FirstViewController: UIViewController {
@IBOutlet weak var bgImage: UIImageView!
@IBOutlet weak var mainView: UIView!
@IBOutlet weak var titleLabel: UILabel!
@IBOutlet weak var findButton: UIButton!
@IBOutlet weak var mainViewConstraint: NSLayoutConstraint!
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
mainViewConstraint.constant = -195
for i in [mainView, titleLabel, findButton] {
i?.alpha = 0
}
UIView.animate(withDuration: 1, animations: {
}) { (true) in
self.animateView()
}
}
func animateView() {
UIView.animate(withDuration: 2, animations: {
self.mainView.alpha = 1
self.mainViewConstraint.constant = 0
self.view.layoutIfNeeded()
}) { (true) in
self.animateLbl()
}
}
func animateLbl() {
UIView.animate(withDuration: 1, animations: {
self.titleLabel.alpha = 1
}) { (true) in
self.animateBtn()
}
}
func animateBtn() {
UIView.animate(withDuration: 1) {
self.findButton.alpha = 1
}
}
}
发布于 2018-06-28 06:32:55
为了解决这个问题,我在故事板中将mainViewConstraint的位置更改为-195,并对代码进行了以下更改:
mainViewConstraint.constant = 0 //-195
for i in [mainView, titleLbl, findBtn] {
i?.alpha = 0
}
UIView.animate(withDuration: 1, animations: {
self.bgImage.alpha = 1
}) { (true) in
self.animateView()
}
}
func animateView() {
UIView.animate(withDuration: 2, animations: {
self.mainView.alpha = 1
//self.mainViewConstraint.constant = 0
self.view.layoutIfNeeded()
发布于 2018-06-25 19:22:01
在您的代码中,您在动画块中调用animateView(),这似乎是问题所在。
将它移出动画块应该可以解决这个问题。
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
mainViewConstraint.constant = -195
for i in [mainView, titleLabel, findButton] {
i?.alpha = 0
}
self.animateView()
}
https://stackoverflow.com/questions/51013654
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