简介
本人最近一直在学习Swift编程，然后遇到自定义过场动画的问题，再次做一个小小的总结，也希望能给同时也在学习Swift的朋友一些帮助。如果想了解OC的自定义过场动画，推荐阅读 iOS自定义转场动画/UIPresentationController，讲解的非常细致，而且有demo代码。
Demo 下载
如果不想下载请看文章最后的全部代码
第一部分
首先我们需要创建一个CustomPresentationManager类
成员变量
//用于指定presentationController的frame
var presentedFrame = CGRect.zero
//用于标记presentation视图是否已经显示
var isPresented = false
协议
CustomPresentationManager类需要继承两个协议分别是：UIViewControllerTransitioningDelegate
UIViewControllerAnimatedTransitioning
在UIViewControllerTransitionDelegate中需要实现三个方法，分别是
1.presentationController()
func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController?{
//创建presentationController
let dialog = DialogPresentationController.init(presentedViewController: presented, presenting: presenting)
//设置Controller中成员变量的值
dialog.presentedFrame = presentedFrame
//返回指定的presentationController
return dialog
}
这个函数主要用于指定PresentationController
2.animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning?
func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning?{
isPresented = false
NSLog("Show")
return self
}
这个函数会在presented视图出现的时候被调用， 在此函数中可以进行一些需要在presented视图出现之后进行的操作。 需要注意的是在这个函数中需要把isPresented置为false,原因稍后说明。
- animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning?
func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning?{
isPresented = true
NSLog("Disappear")
return self
}
这个函数的作用正好和上一个相反，在presentation视图消失的时候会被调用，并在此函数中把isPresented置为false。
UIViewControllerAnimatedTransitioning协议主要用于指定transitioning的时间和动画的细节，其中需要实现两个方法。
- transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval{
return 0.8
}
这个函数并没有什么好说的，需要返回transitioning 的时间。
- animateTransition(using transitionContext: UIViewControllerContextTransitioning)
func animateTransition(using transitionContext: UIViewControllerContextTransitioning){
if isPresented{
disappear(transitionContext: transitionContext)
}else{
showUp(transitionContext: transitionContext)
}
}
这个函数需要注意的地方是，在transition开始和结束的时候，该函数都会被调用，所以这也是上文提到的isPresented变量需要被用到的地方。需要根据isPresented来判断Presentation视图是否展示，从而指定不同的transition方式。值得一提的是transitionContext这个变量，transition所需要的东西全部都包含在这个变量里面。showUp和disappear函数指定了具体的transition方式，具体细节请参考上文中的Demo代码。
第二部分
这个部分主要介绍自定义的UIPresentationController里面的一些细节和注意点。
这部分的代码比较少而且很简单，就全部粘出来吧。
import UIKit
class DialogPresentationController: UIPresentationController {
var presentedFrame = CGRect.zero
var isLayout = false
override func containerViewDidLayoutSubviews(){
if !isLayout {
presentedView?.frame = presentedFrame
containerView?.insertSubview(coverbutton, at: 0)
coverbutton.addTarget(self, action: #selector(closeDialog), for: .touchUpInside)
isLayout = true
}
}
func closeDialog(){
presentedViewController.dismiss(animated: true, completion: nil)
}
private lazy var coverbutton: UIButton = {
let btn = UIButton.init(frame: UIScreen.main.bounds)
btn.backgroundColor = UIColor.lightGray
btn.alpha = 0.8
return btn
}()
}
最需要注意的是containerViewDidLayoutSubviews方法在presented视图展示和消失的时候都会被调用。如果不用isLayout判断是否layout过就会重复layout，导致一些奇奇怪怪的错误。
全部代码：
CustomTransitioningManager
//
// CustomTransition.swift
// AnimationTest
//
// Created by Albert-z on 2017-05-14.
// Copyright © 2017 Albert-z. All rights reserved.
//
import UIKit
class CustomTransitioningManager: NSObject, UIViewControllerTransitioningDelegate,UIViewControllerAnimatedTransitioning {
//用于指定presentationController的frame
var presentedFrame = CGRect.zero
//用于标记presentation视图是否已经显示
var isPresented = false
//MARK:UIViewControllerAnimatedTransitioning
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval{
return 0.8
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning){
if isPresented{
disappear(transitionContext: transitionContext)
}else{
showUp(transitionContext: transitionContext)
}
}
//MARK:UIViewControllerTransitioningDelegate
func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController?{
//创建presentationController
let dialog = DialogPresentationController.init(presentedViewController: presented, presenting: presenting)
//设置Controller中成员变量的值
dialog.presentedFrame = presentedFrame
//返回指定的presentationController
return dialog
}
func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning?{
isPresented = false
NSLog("Show")
return self
}
func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning?{
isPresented = true
NSLog("Disappear")
return self
}
//MARK:Custom func
func showUp(transitionContext: UIViewControllerContextTransitioning){
let view = transitionContext.view(forKey: .to)
transitionContext.containerView.addSubview(view!)
view?.transform = .init(scaleX: 0.0, y: 0.0)
view?.layer.anchorPoint = .init(x: 0.5, y: 0.5)
UIView.animate(withDuration: 0.5, animations: {
view?.transform = .identity
}) { (_) in
transitionContext.completeTransition(true)
}
}
func disappear(transitionContext: UIViewControllerContextTransitioning){
let view = transitionContext.view(forKey: .from)
view?.transform = .init(scaleX: 1.0, y: 1.0)
UIView.animate(withDuration: 0.5, animations: {
view?.transform = .init(scaleX: 1.0, y: 0.001)
}) { (_) in
transitionContext.completeTransition(true)
}
}
}
DialogPresentationController
//
// DialogPresentationController.swift
// AnimationTest
//
// Created by Albert-z on 2017-05-14.
// Copyright © 2017 Albert-z. All rights reserved.
//
import UIKit
class DialogPresentationController: UIPresentationController {
var presentedFrame = CGRect.zero
var isLayout = false
override func containerViewDidLayoutSubviews(){
if !isLayout {
presentedView?.frame = presentedFrame
containerView?.insertSubview(coverbutton, at: 0)
coverbutton.addTarget(self, action: #selector(closeDialog), for: .touchUpInside)
isLayout = true
}
}
func closeDialog(){
presentedViewController.dismiss(animated: true, completion: nil)
}
private lazy var coverbutton: UIButton = {
let btn = UIButton.init(frame: UIScreen.main.bounds)
btn.backgroundColor = UIColor.lightGray
btn.alpha = 0.8
return btn
}()
}
ViewController
//
// ViewController.swift
// AnimationTest
//
// Created by Albert-z on 2017-05-13.
// Copyright © 2017 Albert-z. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
var window: UIWindow?
var manager:CustomTransitioningManager?
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func btnClick(_ sender: Any) {
manager = CustomTransitioningManager.init()
manager?.presentedFrame = CGRect.init(x: UIScreen.main.bounds.width/2 - 150.0, y: UIScreen.main.bounds.height/2 - 100.0, width: 300, height: 150)
let sb = UIStoryboard.init(name: "DialogVC", bundle: nil)
let dialogVC = sb.instantiateInitialViewController()
dialogVC?.modalPresentationStyle = .custom
dialogVC?.transitioningDelegate = manager
present(dialogVC!, animated: true, completion: nil)
}
}