如何在XCode Swift 5中播放简单的淡入淡出动画和按钮移动

Question

我试图在viewDidAppear((：

override func viewDidAppear(_ animated: Bool) {
self.button.frame.origin.y -= 90
self.button.frame.origin.x -= 10
}
override func viewWillAppear(_ animated: Bool) {
button.alpha=0
}

Answer 1

在viewWillAppear((中，首先将按钮的alpha设置为0，然后在viewDidAppear中将其动画化，如下所示：

override func viewDidAppear(_ animated: Bool) {
UIView.animate(withDuration: 2.0) {
self.button.alpha = 1
self.button.frame.origin.y -= 90
self.button.frame.origin.x -= 10
}
}
override func viewWillAppear(_ animated: Bool) {
button.alpha=0
}