這篇文章中我們主要來敘述一下上述動畫效果的實現(xiàn)方案。主要涉及 View Controller 轉(zhuǎn)場動畫的知識。
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Presenting a View Controller
顯示一個 View Controller 主要有一下幾種方式：
通過上述方式，我們可以將一個 View Controller 顯示出來，而對于顯示地形式，我們可以使用 UIKit 中預(yù)定義的形式，也可以自定義（即自定義轉(zhuǎn)場動畫）。
Customizing the Transition Animations
自定義轉(zhuǎn)場動畫中，主要包含以下幾個組件：
實現(xiàn)自定義轉(zhuǎn)場動畫，通常按照以下幾個步驟來完成
Presented View Controller
這里，我們將 Presented View Controller 本身作為其轉(zhuǎn)場代理，你也可以使用單獨的代理對象。
class PresentedViewController: UIViewController { let imageView = UIImageView(image: UIImage(named: "jd_add.jpg")) override func android/221584.html">viewDidLoad() { super.viewDidLoad() // 1.設(shè)置 transitioningDelegate（轉(zhuǎn)場代理） transitioningDelegate = self modalPresentationStyle = .custom view.addSubview(imageView) } override func viewDidLayoutSubviews() { super.viewDidLayoutSubviews() imageView.frame = CGRect(x: 0, y: 120, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height - 120) } override func touchesBegan(_ touches: Set, with event: UIEvent?) { self.dismiss(animated: true, completion: nil) }}Animator
Animator 作為轉(zhuǎn)場動畫的管理者，主要負(fù)責(zé) Presenting 和 Dismissing 動畫效果。
動畫時長
/// 轉(zhuǎn)場動畫時長func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval { return TimeInterval(0.5)}執(zhí)行動畫
/// 執(zhí)行轉(zhuǎn)場動畫func animateTransition(using transitionContext: UIViewControllerContextTransitioning) { switch type { case .Present: present(transitionContext: transitionContext) case .Dismiss: dismiss(transitionContext: transitionContext) }}Presenting 動畫
/// Presenting 動畫func present(transitionContext: UIViewControllerContextTransitioning) { /** 1.從轉(zhuǎn)場上下文中取出 Presenting/Pressented View Controller 及容器視圖 */ guard let presentingVC = transitionContext.viewController(forKey: .from) as? ViewController else { return } guard let presentedVC = transitionContext.viewController(forKey: .to) as? PresentedViewController else { return } let containerView = transitionContext.containerView /** 2.設(shè)置 Presenting View Controller 所顯示內(nèi)容的屬性 */ // 對 presentingVC 的視圖內(nèi)容截屏，用于 presentedVC 顯示出來時的背景 guard let presentingVCViewSnapshot = presentingVC.view.snapshotView(afterScreenUpdates: false) else { return } // 隱藏 presentingVC 的 view，并將其截屏添加到 containerView 中 presentingVC.view.isHidden = true containerView.addSubview(presentingVCViewSnapshot) // 改變 presentingVCViewSnapshot 的焦點 presentingVCViewSnapshot.layer.anchorPoint = CGPoint(x: 0.5, y: 1) // 更新 presentingVCViewSnapshot 的 frame presentingVCViewSnapshot.frame = presentingVC.view.frame /** 3.設(shè)置 Presented View Controller 所顯示內(nèi)容的屬性 */ presentedVC.view.frame = CGRect(x: 0, y: containerView.bounds.height, width: containerView.bounds.width, height: containerView.bounds.height) containerView.addSubview(presentedVC.view) /** 4.設(shè)置 Presenting 轉(zhuǎn)場動畫 */ UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: { // 改變 presentingVCViewSnapshot 的 layer 的 transform，使其繞 X軸 旋轉(zhuǎn)，并改變大小 presentingVCViewSnapshot.layer.transform.m34 = -1 / 100.0 presentingVCViewSnapshot.layer.transform = presentingVCViewSnapshot.layer.transform = CATransform3DConcat(CATransform3DMakeRotation(CGFloat(0.1), 1, 0, 0), CATransform3DMakeScale(0.85, 0.95, 1)) // 改變 presentedVC 的 view 的 transform presentedVC.view.transform = CGAffineTransform(translationX: 0, y: -containerView.bounds.height) }) { (finished) in // 告知 UIKit Presenting 轉(zhuǎn)場動畫結(jié)束（很重要） transitionContext.completeTransition(true) }}Dismissing 動畫
/// Dismissing 動畫func dismiss(transitionContext: UIViewControllerContextTransitioning) { /** 1.從轉(zhuǎn)場上下文中取出容器視圖、Presenting/Pressented View Controller 及其 view 的截屏 */ let containerView = transitionContext.containerView guard let presentingVC = transitionContext.viewController(forKey: .from) as? PresentedViewController else { return } guard let presentedVC = transitionContext.viewController(forKey: .to) as? ViewController else { return } let subviewsCount = containerView.subviews.count let presentedVCViewSnapshot = containerView.subviews[subviewsCount - 2] /** 2.設(shè)置 Dismissing 轉(zhuǎn)場動畫 */ UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: { // 將 presentedVCViewSnapshot 的 transform 恢復(fù)到初始值 presentedVCViewSnapshot.layer.transform = CATransform3DIdentity // 將 presentedVC 的 view 的 transform 恢復(fù)到初始值 presentingVC.view.transform = CGAffineTransform.identity }) { (finished) in // 使 presentedVC 的 view 顯示出來，并隱藏其截屏 presentedVC.view.isHidden = false presentedVCViewSnapshot.removeFromSuperview() // 告知 UIKit Dismissing 轉(zhuǎn)場動畫結(jié)束（很重要） transitionContext.completeTransition(true) }}Transitioning Delegate
// MARK: - 2.實現(xiàn) UIViewControllerTransitioningDelegate 提供 Animatorextension PresentedViewController: UIViewControllerTransitioningDelegate { /// Present func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? { return MyAnimator(type: .Present) } /// Dismiss func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? { return MyAnimator(type: .Dismiss) }}Present@IBAction func present() { let presentedVC = PresentedViewController() present(presentedVC, animated: true, completion: nil)}關(guān)于 View Controller Transition 就介紹到這里，你應(yīng)該熟悉了其使用方法，至于博客中的動畫效果，我想就沒辦法深究了，這是一個花費時間苦差事。如果大家有任何疑問請給我留言，小編會及時回復(fù)大家的。在此也非常感謝大家對VEVB武林網(wǎng)網(wǎng)站的支持！
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