1.CATransition

CATransition是CAAnimation的子类，用于过渡动画或转场动画。为视图层移入移除屏幕提供转场动画。首先来看一下简单的Demo：

CATransition *animation = [CATransition animation]; animation.type = kCATransitionFade; animation.subtype = kCATransitionFromRight; animation.duration = 1.0; // 在window上执行CATransition, 即可在ViewController转场时执行动画 [self.view.window.layer addAnimation:animation forKey:@"kTransitionAnimation"]; AViewController *vc = [[AViewController alloc] init]; [self presentViewController:vc animated:NO completion:nil];

将该动画添加到window.layer上，则会present或push时使用指定的转场动画。

其中最主要的两个属性就是type和subtype。

type：转场动画的类型。

官方SDK只提供了四种转场动画的类型，即:

CA_EXTERN NSString * const kCATransitionFade;CA_EXTERN NSString * const kCATransitionMoveIn;CA_EXTERN NSString * const kCATransitionPush;CA_EXTERN NSString * const kCATransitionReveal;

私有的type：

NSString *const kCATransitionCube = @"cube";NSString *const kCATransitionSuckEffect = @"suckEffect";NSString *const kCATransitionOglFlip = @"oglFlip";NSString *const kCATransitionRippleEffect = @"rippleEffect";NSString *const kCATransitionPageCurl = @"pageCurl";NSString *const kCATransitionPageUnCurl = @"pageUnCurl";NSString *const kCATransitionCameraIrisHollowOpen = @"cameraIrisHollowOpen";NSString *const kCATransitionCameraIrisHollowClose = @"cameraIrisHollowClose";

subtype:动画类型的方向

CA_EXTERN NSString * const kCATransitionFromRight;CA_EXTERN NSString * const kCATransitionFromLeft;CA_EXTERN NSString * const kCATransitionFromTop;CA_EXTERN NSString * const kCATransitionFromBottom;

上面讲的是给window.layer添加transition，这样使得在present或push时使用指定的转场动画。

既然讲到这里了，就看一下把transition加在layer上。

看一下示例代码：

- (void)viewDidLoad { [super viewDidLoad]; UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(100, 100, 100, 50)]; [button setTitle:@"进入" forState:UIControlStateNormal]; button.backgroundColor = [UIColor redColor]; [button addTarget:self action:@selector(buttonClicked) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:button]; _imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 300, 150, 150)]; [self.view addSubview:_imageView]; _imageView.backgroundColor = [UIColor redColor]; _imageArray = @[[UIImage imageNamed:@"成果秀1"],[UIImage imageNamed:@"点赞他人1"],[UIImage imageNamed:@"偷师学艺1"],[UIImage imageNamed:@"学会欣赏3"]]; _imageView.image = [UIImage imageNamed:@"成果秀1"];}- (void)buttonClicked{ CATransition *animation = [CATransition animation]; animation.type = @"cube"; animation.subtype = kCATransitionFromRight; animation.duration = 1.0; //换图片的时候使用转场动画 [self.imageView.layer addAnimation:animation forKey:nil]; //cycle to next image UIImage *currentImage = self.imageView.image; NSUInteger index = [self.imageArray indexOfObject:currentImage]; index = (index + 1) % [self.imageArray count]; self.imageView.image = self.imageArray[index];}

2.transitionFromViewController

UIViewController自带的方法:transitionFromViewController:toViewController:duration:options:animations:completion:这个转场动画是用在当一个父视图控制器中有几个childViewController，当要在这几个子视图控制器之间切换时就可以用这个方法。

AViewController *a = self.childViewControllers[0];BViewController *b = self.childViewControllers[1];CViewController *c = self.childViewControllers[2];// Curl 翻页效果// UIViewAnimationOptionTransitionCurlUp, UIViewAnimationOptionTransitionCurlDown// Flip 翻转效果// UIViewAnimationOptionTransitionFlipFromLeft, UIViewAnimationOptionTransitionFlipFromRight// UIViewAnimationOptionTransitionFlipFromTop, UIViewAnimationOptionTransitionFlipFromDown[self transitionFromViewController:_currentViewController   toViewController:b    duration:0.5    options:UIViewAnimationOptionTransitionFlipFromRight   animations:^{} completion:^(BOOL finished) {}];

3.Transition Animation

1 UINavigationControllerDelegate + UIViewControllerAnimatedTransitioning

在UINavigationController的转场动画中，要指定UINavigationControllerDelegate对象：

self.navigationController.delegate = self;[self.navigationController pushViewController:itemVC animated:YES];

UINavigationControllerDelegate主要有以下两个协议方法：

//pop- (nullable id )navigationController:(UINavigationController *)navigationController       interactionControllerForAnimationController:(id ) animationController NS_AVAILABLE_IOS(7_0);//push- (nullable id )navigationController:(UINavigationController *)navigationController         animationControllerForOperation:(UINavigationControllerOperation)operation            fromViewController:(UIViewController *)fromVC             toViewController:(UIViewController *)toVC NS_AVAILABLE_IOS(7_0);

首先创建一个基类PDAnimatorBaseTransition实现UIViewControllerAnimatedTransitioning协议的方法。

UIViewControllerAnimatedTransitioning协议的方法有：

//动画持续时间- (NSTimeInterval)transitionDuration:(nullable id )transitionContext;//转场动画实现细节- (void)animateTransition:(id )transitionContext;动画结束时调用- (void)animationEnded:(BOOL) transitionCompleted;

PDAnimatorBaseTransition.h

#import #import typedef NS_ENUM(NSInteger, PDAnimationType){ animationTypePresent = 0, animationTypeDismiss , animationTypePush , animationTypePop,};@interface PDAnimatorBaseTransition : NSObject @property (nonatomic, assign)PDAnimationType animationType;@property (nonatomic, strong)UIView *containerView;@property (nonatomic, strong)UIViewController *from;@property (nonatomic, strong)UIViewController *to;@property (nonatomic, strong)UIView *fromView;@property (nonatomic, strong)UIView *toView;@property (nonatomic, weak)id transitionContext;@end

PDAnimatorBaseTransition.m

#import "PDAnimatorBaseTransition.h"@interface PDAnimatorBaseTransition()@end@implementation PDAnimatorBaseTransition#pragma mark -required- (NSTimeInterval)transitionDuration:(nullable id )transitionContext{ return 1.f;}- (void)animateTransition:(id )transitionContext{ _transitionContext = transitionContext; _containerView = [transitionContext containerView]; _from = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]; _to = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]; if([transitionContext respondsToSelector:@selector(viewForKey:)]){  _fromView = [transitionContext viewForKey:UITransitionContextFromViewKey];  _toView = [transitionContext viewForKey:UITransitionContextToViewKey]; }else{  _fromView = _from.view;  _toView = _to.view; } if(self.animationType == animationTypePresent){  [self animationPresent]; }else if (self.animationType == animationTypeDismiss){  [self animationDismiss]; }else if (self.animationType == animationTypePop){  [self animationPop]; }else{  [self animationPush]; }}#pragma mark -optional//动画结束时回调- (void)animationEnded:(BOOL) transitionCompleted{}- (void)animationPresent{}- (void)animationDismiss{}- (void)animationPop{}- (void)animationPush{}

然后创建子类PDAnimatorPUshPopTransition继承自PDAnimatorBaseTransition，实现- (void)animationPush，- (void)animationPop方法。

PDAnimatorPUshPopTransition.h

#import "PDAnimatorBaseTransition.h"#import @interface PDAnimatorPUshPopTransition : PDAnimatorBaseTransition@property (nonatomic, assign)CGPoint itemCenter;@property (nonatomic, assign)CGSize itemSize;@property (nonatomic, strong)NSString *imageName;@end

PDAnimatorPUshPopTransition.m

#import "PDAnimatorPUshPopTransition.h"@implementation PDAnimatorPUshPopTransition- (instancetype)init{ self = [super init]; if(self){ } return self;}- (NSTimeInterval)transitionDuration:(nullable id )transitionContext{ return 5.f;}- (void)animateTransition:(id )transitionContext{ [super animateTransition:transitionContext];}- (void)animationPush{ NSTimeInterval duration = [self transitionDuration:self.transitionContext]; __weak typeof(self) weakSelf = self; self.containerView.backgroundColor = [UIColor lightGrayColor]; UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 100, 160)]; imageView.image = [UIImage imageNamed:self.imageName]; imageView.center = _itemCenter; CGFloat initialScale = _itemSize.width / CGRectGetWidth(imageView.frame); CGAffineTransform transform = CGAffineTransformIdentity; transform = CGAffineTransformScale(transform, initialScale, initialScale); transform = CGAffineTransformRotate(transform, M_PI); imageView.layer.affineTransform = transform; // imageView.transform = CGAffineTransformMakeScale(initialScale, initialScale); [self.containerView addSubview:imageView]; self.toView.frame = [self.transitionContext finalFrameForViewController:self.to]; CGPoint finalCenter = self.toView.center; self.toView.center = finalCenter; self.toView.alpha = 0.0; //这一句一定要 [self.containerView addSubview:self.toView]; [UIView animateWithDuration:duration delay:0 usingSpringWithDamping:0.5 initialSpringVelocity:0 options:UIViewAnimationOptionCurveLinear animations:^{  imageView.layer.affineTransform = CGAffineTransformIdentity;  imageView.center = finalCenter;  self.fromView.alpha = 0.0;  self.containerView.backgroundColor = [UIColor redColor]; } completion:^(BOOL finished){  [imageView removeFromSuperview];  weakSelf.toView.alpha = 1.0f;  weakSelf.fromView.alpha = 1.0f;  [weakSelf.transitionContext completeTransition:![weakSelf.transitionContext transitionWasCancelled]]; }];}- (void)animationPop{ NSTimeInterval duration = [self transitionDuration:self.transitionContext]; __weak typeof(self) weakSelf = self; self.toView.frame = [self.transitionContext finalFrameForViewController:self.to]; [self.containerView insertSubview:self.toView belowSubview:self.fromView]; self.fromView.alpha = 0.0; self.fromView.backgroundColor = [UIColor clearColor]; [UIView animateWithDuration:duration delay:0 usingSpringWithDamping:0.5 initialSpringVelocity:0 options:UIViewAnimationOptionCurveLinear animations:^{  CGFloat initialScale = _itemSize.width / 200;  weakSelf.fromView.transform = CGAffineTransformMakeScale(initialScale, initialScale);  weakSelf.fromView.center = weakSelf.itemCenter;  weakSelf.toView.alpha = 1.0f; } completion:^(BOOL finished){  weakSelf.fromView.alpha = 0.0f;  [weakSelf.transitionContext completeTransition:![weakSelf.transitionContext transitionWasCancelled]]; }];}@end

然后我们在需要push的地方实现UINavigationControllerDelegate的协议方法：

- (nullable id )navigationController:(UINavigationController *)navigationController           animationControllerForOperation:(UINavigationControllerOperation)operation               fromViewController:(UIViewController *)fromVC               toViewController:(UIViewController *)toVC NS_AVAILABLE_IOS(7_0){ PDAnimatorPUshPopTransition *animationTransition = [[PDAnimatorPUshPopTransition alloc] init]; if(operation == UINavigationControllerOperationPush){  animationTransition.animationType = animationTypePush; }else if (operation == UINavigationControllerOperationPop){  animationTransition.animationType = animationTypePop; } NSArray *indexPaths = [self.collectionView indexPathsForSelectedItems]; if (indexPaths.count == 0) {  return nil; } NSIndexPath *selectedIndexPath = indexPaths[0]; UICollectionViewCell *cell = [self.collectionView cellForItemAtIndexPath:selectedIndexPath]; // 一定要加上convertPoint:toView:操作 animationTransition.itemCenter = [self.collectionView convertPoint:cell.center toView:self.view]; animationTransition.itemSize = cell.frame.size; animationTransition.imageName = [NSString stringWithFormat:@"%ld", (long)selectedIndexPath.item]; return animationTransition;}

2 UIViewControllerTransitioningDelegate+UIViewControllerAnimatedTransitioning

首先需要设置被present的Controller的transitionDelegate

DemoViewControllerTransitionPresentedViewController *presentedVC = [[DemoViewControllerTransitionPresentedViewController alloc] init];presentedVC.transitionDelegate = self;[self presentViewController:presentedVC animated:YES completion:nil];

UIViewControllerTransitioningDelegate的代理的协议方法有：

//  prenent- (id )animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source;//  pop- (id )animationControllerForDismissedController:(UIViewController *)dismissed;//  prenent- (id )interactionControllerForPresentation:(id )animator;//  pop- (nullable id )interactionControllerForDismissal:(id )animator;

创建子类PDAnimationPresentTransitio继承自基类PDAnimatorBaseTransition，实现- (void)animationPresent，- (void)animationDismiss方法。

PDAnimationPresentTransition.h

#import "PDAnimatorBaseTransition.h"@interface PDAnimationPresentTransition : PDAnimatorBaseTransition@end

PDAnimationPresentTransition.m

#import "PDAnimationPresentTransition.h"@implementation PDAnimationPresentTransition- (NSTimeInterval)transitionDuration:(nullable id )transitionContext{ return 1.f;}- (void)animateTransition:(id )transitionContext{ [super animateTransition:transitionContext];}- (void)animationPresent{ NSTimeInterval duration = [self transitionDuration:self.transitionContext]; __weak typeof(self) weakSelf = self; self.toView.frame = [self.transitionContext initialFrameForViewController:self.to]; self.fromView.frame = [self.transitionContext initialFrameForViewController:self.from]; CGAffineTransform transform = CGAffineTransformIdentity; transform = CGAffineTransformScale(transform, 0.001, 0.001); self.toView.layer.affineTransform = transform; [self.containerView addSubview:self.toView]; self.toView.alpha = 0.0; [UIView animateWithDuration:duration delay:0 usingSpringWithDamping:0.6 initialSpringVelocity:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{  self.toView.layer.affineTransform = CGAffineTransformIdentity;  self.toView.frame = [self.transitionContext finalFrameForViewController:self.to];  self.toView.alpha = 1.0; } completion:^(BOOL finished){  BOOL wasCancelled = [weakSelf.transitionContext transitionWasCancelled];  [weakSelf.transitionContext completeTransition:!wasCancelled]; }];}

然后我们在需要present的地方实现UIViewControllerTransitioningDelegate的代理方法。

- (nullable id )animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source{ PDAnimationPresentTransition *animationTransition = [[PDAnimationPresentTransition alloc] init]; animationTransition.animationType = animationTypePresent; return animationTransition;}- (nullable id )animationControllerForDismissedController:(UIViewController *)dismissed{ PDAnimationPresentTransition *animationTransition = [[PDAnimationPresentTransition alloc] init]; animationTransition.animationType = animationTypePresent; return animationTransition;}