iOS-自定義控制器轉(zhuǎn)場(chǎng)動(dòng)畫(huà)（present/dismiss）

一誓琼、轉(zhuǎn)場(chǎng)動(dòng)畫(huà)類(lèi)型

iOS控制器轉(zhuǎn)場(chǎng)動(dòng)畫(huà)類(lèi)型可以分為非交互式轉(zhuǎn)場(chǎng)動(dòng)畫(huà)和交互式轉(zhuǎn)場(chǎng)動(dòng)畫(huà)检激。

二、轉(zhuǎn)場(chǎng)動(dòng)畫(huà)分析

2.1腹侣、轉(zhuǎn)場(chǎng)代理

自定義控制器轉(zhuǎn)場(chǎng)動(dòng)畫(huà)需要重新實(shí)現(xiàn)控制器的轉(zhuǎn)場(chǎng)代理方法UIViewControllerTransitioningDelegate叔收。

//控制器present時(shí)執(zhí)行的代理方法
func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning?

//控制器dismiss時(shí)執(zhí)行的代理方法
func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning?

//交互式轉(zhuǎn)場(chǎng)時(shí)控制器present執(zhí)行的代理方法
func interactionControllerForPresentation(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning?

//交互式轉(zhuǎn)場(chǎng)是控制器dismiss執(zhí)行的代理方法
func interactionControllerForDismissal(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning?

//定義控制器轉(zhuǎn)場(chǎng)過(guò)程
func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController?

自定義轉(zhuǎn)場(chǎng)代理方法需要將PresentedViewController的modalPresentationStyle設(shè)為custom或者fullScreen下才執(zhí)行。
custom和fullScreen的區(qū)別是：
fullScreen模式：控制器presentation 后傲隶，presentingView 會(huì)被主動(dòng)移出視圖結(jié)構(gòu)饺律，在 dismissal 中 presentingView 是 toView 的角色，其將會(huì)重新加入 containerView 中跺株。
custom模式：在 presentation 后复濒，presentingView 未被移出視圖結(jié)構(gòu)，在 dismissal 中乒省，不要將 presentingView 加入 containerView 中巧颈，否則本來(lái)可見(jiàn)的 presentingView 將會(huì)被移除出自身所處的視圖結(jié)構(gòu)消失不見(jiàn)。

2.2袖扛、動(dòng)畫(huà)協(xié)議

控制器的動(dòng)畫(huà)協(xié)議UIViewControllerAnimatedTransitioning主要負(fù)責(zé)動(dòng)畫(huà)的執(zhí)行過(guò)程砸泛。

//動(dòng)畫(huà)的執(zhí)行時(shí)間
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval

//動(dòng)畫(huà)的具體執(zhí)行過(guò)程在這個(gè)方法中實(shí)現(xiàn)
func animateTransition(using transitionContext: UIViewControllerContextTransitioning)

//是否使能動(dòng)畫(huà)
func animationEnded(_ transitionCompleted: Bool)

2.3、動(dòng)畫(huà)的承載

UIViewControllerContextTransitioning協(xié)議承載了動(dòng)畫(huà)的重要參數(shù)蛆封，在轉(zhuǎn)場(chǎng)之前可以得到遵守寫(xiě)的的對(duì)象transitionContext唇礁，通過(guò)這個(gè)對(duì)象可以獲取動(dòng)畫(huà)所需的參數(shù)。

//容器View娶吞，承載轉(zhuǎn)場(chǎng)動(dòng)畫(huà)
public var containerView: UIView { get }

//獲取參與轉(zhuǎn)場(chǎng)的控制器
public func viewController(forKey key: UITransitionContextViewControllerKey) -> UIViewController?

//獲取轉(zhuǎn)場(chǎng)視圖
public func view(forKey key: UITransitionContextViewKey) -> UIView?

三垒迂、轉(zhuǎn)場(chǎng)動(dòng)畫(huà)實(shí)現(xiàn)

3.1、非交互式轉(zhuǎn)場(chǎng)動(dòng)畫(huà)

3.1.1妒蛇、轉(zhuǎn)場(chǎng)動(dòng)畫(huà)的具體實(shí)現(xiàn)

創(chuàng)建一個(gè)遵守UIViewControllerAnimatedTransitioning協(xié)議的類(lèi)MaskAnimatedTransition机断，用于實(shí)現(xiàn)具體的動(dòng)畫(huà)。
實(shí)現(xiàn)協(xié)議方法：

func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
    return 0.3
}

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    if modalType == .present {
        presentAnimateTransition(using: transitionContext)
    } else {
        dismissAnimateTransition(using: transitionContext)
    }
}

創(chuàng)建兩個(gè)私有的方法绣夺，分別實(shí)現(xiàn)控制器present和dismiss轉(zhuǎn)場(chǎng)時(shí)的動(dòng)畫(huà)：

private func presentAnimateTransition(using transitionContext: UIViewControllerContextTransitioning) {
     ......
}

private func dismissAnimateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    ......
}

創(chuàng)建一個(gè)枚舉類(lèi)型吏奸，用于判斷控制器的轉(zhuǎn)場(chǎng)類(lèi)型

enum MaskAnimatedTransitionModalType {
    case present
    case dismiss
}

3.1.2、重寫(xiě)轉(zhuǎn)場(chǎng)代理協(xié)議

創(chuàng)建一個(gè)新的類(lèi)陶耍，遵守控制器轉(zhuǎn)場(chǎng)代理協(xié)議UIViewControllerTransitioningDelegate奋蔚，實(shí)現(xiàn)協(xié)議方法。

func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return MaskAnimatedTransition(.present)
}

func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return MaskAnimatedTransition(.dismiss)
}

3.1.3、設(shè)置轉(zhuǎn)場(chǎng)代理

創(chuàng)建一個(gè)全局的轉(zhuǎn)場(chǎng)代理：

let maskTransitionDelegate = MaskTransitionDelegate()

將控制器的轉(zhuǎn)場(chǎng)代理transitioningDelegate設(shè)為maskTransitionDelegate泊碑，將控制器的modalPresentationStyle設(shè)為custom坤按，即可進(jìn)行控制器的模態(tài)轉(zhuǎn)場(chǎng)。
上述控制的轉(zhuǎn)場(chǎng)動(dòng)畫(huà)是一個(gè)漸入漸出的動(dòng)畫(huà)類(lèi)型馒过，動(dòng)畫(huà)時(shí)間為0.3秒臭脓。

3.2交互式轉(zhuǎn)場(chǎng)動(dòng)畫(huà)的實(shí)現(xiàn)

交互式轉(zhuǎn)場(chǎng)動(dòng)畫(huà)相對(duì)非交互動(dòng)畫(huà)而言要多實(shí)現(xiàn)一個(gè)控制器交互過(guò)渡協(xié)議UIViewControllerInteractiveTransitioning。

3.2.1腹忽、交互式轉(zhuǎn)場(chǎng)動(dòng)畫(huà)的實(shí)現(xiàn)

實(shí)現(xiàn)開(kāi)始交互協(xié)議方法：

func startInteractiveTransition(_ transitionContext: UIViewControllerContextTransitioning) {
    if modalType == .present {
        presentStartInteractiveTransition(transitionContext)
    } else {
        dismissStartInteractiveTransition(transitionContext)
    }
}

在presentedViewController上添加一個(gè)手勢(shì)UIPanGestureRecognizer来累，用于交互：

var presentedViewController: UIViewController? = nil {
    didSet {
        let panGR = UIPanGestureRecognizer(target: self, action: #selector(panGestureReconizerAction(_:)))
        self.presentedViewController?.view.addGestureRecognizer(panGR)
    }
}

在交互方法中實(shí)現(xiàn)具體的動(dòng)畫(huà)：

@objc private func panGestureReconizerAction(_ panGR: UIPanGestureRecognizer) {
    ......
}

3.2.2、實(shí)現(xiàn)交互轉(zhuǎn)場(chǎng)代理方法

在重寫(xiě)轉(zhuǎn)場(chǎng)代理時(shí)窘奏，實(shí)現(xiàn)兩個(gè)交互轉(zhuǎn)場(chǎng)代理方法：

public func interactionControllerForPresentation(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
    return nil
}

public func interactionControllerForDismissal(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
    interaction.modalType = .dismiss
    return interaction.isInteraction ? interaction : nil
}

3.2.3嘹锁、設(shè)置轉(zhuǎn)場(chǎng)代理