好久沒更新了，最近一直比較忙，也是有點(diǎn)懶了沒更新，實(shí)在不好意思，學(xué)習(xí)的步伐不能停下啊。
　　好了，廢話不多說今天來聊一聊iOS的自定義轉(zhuǎn)場(chǎng)的實(shí)現(xiàn)。

簡(jiǎn)述

iOS的新頁(yè)面的彈出方式分為兩種Push&Pop和Present&Dismiss，轉(zhuǎn)場(chǎng)方式的自定義也主要針對(duì)這兩種方式進(jìn)行。其中Push&Pop方式需要針對(duì)Push和Pop分別定義動(dòng)畫，也就是說需要分別創(chuàng)建動(dòng)畫文件。而Present&Dismiss方式的話只需要一個(gè)即可。

Push&Pop方式

動(dòng)畫文件

首先來看一下動(dòng)畫文件的實(shí)現(xiàn)，
1、先創(chuàng)建一個(gè)類繼承自NSObject
2、遵守協(xié)議UIViewControllerAnimatedTransitioning
3、接下來主要實(shí)現(xiàn)三個(gè)方法即可

@interface PushTransition : NSObject<UIViewControllerAnimatedTransitioning>
@property (nonatomic,strong) id transitionContext;//專場(chǎng)上下文，用來協(xié)調(diào)，from和to的頁(yè)面
@property (nonatomic,strong) UIViewController *fromViewController;//push操作主要針對(duì)fromViewController做動(dòng)畫
@end

First

主要用來返回動(dòng)畫執(zhí)行時(shí)間,即為push動(dòng)畫的時(shí)間，直接return一個(gè)時(shí)間即可，單位為秒

- (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext
{
    return 2;
}

Second

下面這個(gè)方法就主要涉及到動(dòng)畫的實(shí)現(xiàn)了，需要對(duì)FromViewController的view做動(dòng)畫，來實(shí)現(xiàn)push的動(dòng)畫效果，主要解釋已在注釋里面寫的很清楚了

- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{_transitionContext = transitionContext;//首先記錄transitionContext，下面的方法會(huì)用到
    //我們主要通過這個(gè)transitionContext來獲取需要做動(dòng)畫的fromViewController和toViewController,fromView和toView
    //通過viewControllerForKey:這個(gè)方法來獲取，有兩個(gè)key來獲取相應(yīng)的Controller
    // Currently only two keys are defined by the system:
    //   UITransitionContextToViewControllerKey  獲取要出現(xiàn)的Controller
    //   UITransitionContextFromViewControllerKey 獲取要消失的Controller
    // Currently only two keys are defined by the system:
    //   UITransitionContextToViewKey //獲取要出現(xiàn)的view即上面toViewController的View
    //   UITransitionContextFromViewKey //獲取要出現(xiàn)的view即fromViewController的View
    UIView *fromView = [transitionContext viewForKey:UITransitionContextFromViewKey];
    UIView *toView = [transitionContext viewForKey:UITransitionContextToViewKey];
    //拿到ContainerView
    UIView *containerView = [transitionContext containerView];
    //把fromView和toView都加到containerView中，在容器中是完成動(dòng)畫
    [containerView addSubview:toView];
    [containerView addSubview:fromView];

    //CATransform3D類型的四維仿射變換矩陣，并且提供預(yù)置好的進(jìn)行旋轉(zhuǎn)、變形之后的仿射變換矩陣，m34來控制透視效果,有興趣的話可以在自己了解一下
    CATransform3D transform = CATransform3DIdentity;
    transform.m34 = -1/500.0;
    fromView.layer.transform = transform;
    fromView.layer.anchorPoint = CGPointMake(0, 0.5);
    fromView.layer.position = CGPointMake(0, CGRectGetMidY(fromView.frame));
    
    //動(dòng)畫變化
    [UIView animateWithDuration:2 animations:^{

        fromView.layer.transform = CATransform3DMakeRotation(-M_PI_2, 0, 1, 0);
        
    } completion:^(BOOL finished) {
// This must be called whenever a transition completes (or is cancelled.)
// Typically this is called by the object conforming to the
// UIViewControllerAnimatedTransitioning protocol that was vended by the transitioning
// delegate.  For purely interactive transitions it should be called by the
// interaction controller. This method effectively updates internal view
// controller state at the end of the transition.
//動(dòng)畫完成后必須調(diào)用
        [_transitionContext finishInteractiveTransition];
        [_transitionContext completeTransition:YES];
    }];
}

Pop的話，其實(shí)跟Push差不多這里就只貼代碼不做過多解釋了

- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{
    return 2;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{
    
    _transitionContext = transitionContext;
    UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    [fromViewController.view.layer removeAllAnimations];    
    UIView *containerView = [transitionContext containerView];
    
    [containerView addSubview:fromViewController.view];
    [containerView addSubview:toViewController.view];
    
    CATransform3D transform = CATransform3DIdentity;
    transform.m34 = -1/500.0;
    toViewController.view.layer.transform = transform;
    toViewController.view.layer.anchorPoint = CGPointMake(0, 0.5);
    toViewController.view.layer.position = CGPointMake(0, CGRectGetMidY(fromViewController.view.frame));
    toViewController.view.layer.transform = CATransform3DMakeRotation(-M_PI_2, 0, 1, 0);
    
    [UIView animateWithDuration:2 animations:^{
        
        toViewController.view.layer.transform = CATransform3DIdentity;
        
    } completion:^(BOOL finished) {
        [_transitionContext finishInteractiveTransition];
        [_transitionContext completeTransition:YES];
    }];
    
}

下面我們來介紹一下present和dismiss

這里先簡(jiǎn)單提一下代理，OC中的代理，實(shí)在是十分好用，為了將我們的代碼耦合性降低。我們可以單獨(dú)生成一個(gè)類，來實(shí)現(xiàn)動(dòng)畫，這樣的話可以精簡(jiǎn)Controller里面的代碼，另外是代碼的復(fù)用性進(jìn)一步增加。動(dòng)畫文件可以單獨(dú)放在任何地方應(yīng)用。
　　下面我們來實(shí)現(xiàn).h

//首先遵循以下兩個(gè)協(xié)議，要實(shí)現(xiàn)自定義轉(zhuǎn)場(chǎng)必須遵守的
@interface ModalTransition : NSObject <UIViewControllerTransitioningDelegate,UIViewControllerAnimatedTransitioning>
@property (nonatomic, assign) BOOL isPresent;//記錄是Present還是Dimiss
@end

.m實(shí)現(xiàn)，這里我只是很簡(jiǎn)單的寫了一個(gè)彈簧動(dòng)畫，對(duì)于動(dòng)畫方式大家可以自由發(fā)揮，寫出更加炫酷的效果

@implementation ModalTransition 

//下面兩個(gè)代理方法要返回一個(gè)遵循UIViewControllerAnimatedTransitioning協(xié)議的對(duì)象，返回self即可。記錄一下是Present還是Dimiss。主要講解我還放在注釋里面
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{
    _isPresent = YES;
    return self;
}
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed{
    _isPresent = NO;
    return self;
}
//返回動(dòng)畫時(shí)間
- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext{
    return 1.0;
}
//根據(jù)_isPresent來執(zhí)行不同的動(dòng)畫
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{
    _isPresent ? [self animationForPresentedView:transitionContext] : [self animationForDismissView:transitionContext];
}
//自定義方法，Present的動(dòng)畫實(shí)現(xiàn)
-(void)animationForPresentedView:(id<UIViewControllerContextTransitioning>)transitionContext{
    UIView *presentedView = [transitionContext viewForKey:UITransitionContextToViewKey];
    UIView *fromView = [transitionContext viewForKey:UITransitionContextFromViewKey];
//注意添加的次序
    [[transitionContext containerView] addSubview:fromView];
    [[transitionContext containerView] addSubview:presentedView];
    presentedView.transform = CGAffineTransformTranslate(presentedView.transform, 0, 667);
    [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0 usingSpringWithDamping:0.6 initialSpringVelocity:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{
        presentedView.transform = CGAffineTransformIdentity;
    } completion:^(BOOL finished) {
//完成后記得調(diào)用completeTransition:方法
        [transitionContext completeTransition:YES];
    }];
}
//自定義方法，Dismiss的動(dòng)畫實(shí)現(xiàn)
-(void)animationForDismissView:(id<UIViewControllerContextTransitioning>)transitionContext{
    UIView *dismissedView = [transitionContext viewForKey:UITransitionContextFromViewKey];
    UIView *toView = [transitionContext viewForKey:UITransitionContextToViewKey];
    [[transitionContext containerView] addSubview:toView];
//注意添加的次序
    [[transitionContext containerView] addSubview:dismissedView];
    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        dismissedView.transform = CGAffineTransformTranslate(dismissedView.transform, 0, 667);
    } completion:^(BOOL finished) {
//完成后記得調(diào)用completeTransition:方法
        [transitionContext completeTransition:YES];
    }];
}
@end

使用方法也標(biāo)簡(jiǎn)單

   PresentViewController *presentController = [[PresentViewController alloc]init];
    presentController.modalTransitionStyle = UIModalPresentationCustom;
    presentController.transitioningDelegate = _Transition;//_Transition即為上面冬瓜文件生成的對(duì)象，這樣就可以使用自定義的present動(dòng)畫
    [self presentViewController:presentController animated:YES completion:nil];

到這里基本就實(shí)現(xiàn)完成了，不管是Pop&Push還是Present&Dismiss你都可以實(shí)現(xiàn)任何你想要的炫酷效果（當(dāng)然前提是你能把炫酷的動(dòng)畫優(yōu)雅的實(shí)現(xiàn)出來），我這里只是拋磚引玉，期待你有更完美，漂亮的動(dòng)畫效果。