swift 自定义Modal动画

//
//  PopoverAnimator.swift
//  DS11WB
//
//  Created by xiaomage on 16/4/6.
//  Copyright © 2016年 小码哥. All rights reserved.
//

import UIKit

class PopoverAnimator: NSObject {
    var isPresented : Bool = false
}

// MARK:- 自定义转场代理的方法
extension PopoverAnimator : UIViewControllerTransitioningDelegate {
    // 目的:改变弹出View的尺寸
    func presentationControllerForPresentedViewController(presented: UIViewController,presentingViewController presenting: UIViewController,sourceViewController source: UIViewController) -> UIPresentationController? {
        return XMGPresentationController(presentedViewController: presented,presentingViewController: presenting)
    }
    
    // 目的:自定义弹出的动画
    func animationControllerForPresentedController(presented: UIViewController,presentingController presenting: UIViewController,sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        isPresented = true
        return self
    }
    
    // 目的:自定义消失的动画
    func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        isPresented = false
        return self
    }
}


// MARK:- 弹出和消失动画代理的方法
extension PopoverAnimator : UIViewControllerAnimatedTransitioning {
    /// 动画执行的时间
    func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return 0.5
    }
    
    /// 获取`转场的上下文`:可以通过转场上下文获取弹出的View和消失的View
    // UITransitionContextFromViewKey : 获取消失的View
    // UITransitionContextToViewKey : 获取弹出的View
    func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
        isPresented ? animationForPresentedView(transitionContext) : animationForDismissedView(transitionContext)
    }
    
    /// 自定义弹出动画
    private func animationForPresentedView(transitionContext: UIViewControllerContextTransitioning) {
        // 1.获取弹出的View
        let presentedView = transitionContext.viewForKey(UITransitionContextToViewKey)!
        
        // 2.将弹出的View添加到containerView中
        transitionContext.containerView()?.addSubview(presentedView)
        
        // 3.执行动画
        presentedView.transform = CGAffineTransformMakeScale(1.0,0.0)
        presentedView.layer.anchorPoint = CGPointMake(0.5,0)
        UIView.animateWithDuration(transitionDuration(transitionContext),animations: { () -> Void in
            presentedView.transform = CGAffineTransformIdentity
            }) { (_) -> Void in
                // 必须告诉转场上下文你已经完成动画
                transitionContext.completeTransition(true)
        }
    }
    
    /// 自定义消失动画
    private func animationForDismissedView(transitionContext: UIViewControllerContextTransitioning) {
        // 1.获取消失的View
        let dismissView = transitionContext.viewForKey(UITransitionContextFromViewKey)
        
        // 2.执行动画
        UIView.animateWithDuration(transitionDuration(transitionContext),animations: { () -> Void in
            dismissView?.transform = CGAffineTransformMakeScale(1.0,0.00001)
            }) { (_) -> Void in
                dismissView?.removeFromSuperview()
                // 必须告诉转场上下文你已经完成动画
                transitionContext.completeTransition(true)
        }
    }
}