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我添加了兩個視圖控制器到我的滾動視圖,並在兩個視圖控制器上都有動畫,但這些動畫只能在vc顯示時調用。相反,當第一個vc顯示時,兩個動畫都正在執行。如何將視圖控制器添加到滾動視圖,但只有在滾動視圖顯示vc時才實例化視圖控制器?
func setUpScrollView() {
for i in 0..<2 {
let vc = NewViewController()
self.addChildViewController(vc)
scrollView.addSubview(vc.view)
vc.didMove(toParentViewController: self)
var frame: CGRect = vc.view.frame
frame.origin.x = self.view.frame.width * CGFloat(i)
vc.view.frame = frame
self.scrollView.contentSize = CGSize(width: self.view.frame.width * CGFloat(2), height: self.view.frame.size.height)
}
}
NewViewController
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print("calling animation") //this is called twice immediatley after for loop, but only shows one vc.
}